220 results on '"Bangs, MJ"'
Search Results
2. Spatial and temporal patterns of dengue in northeastern Thailand 2006-2016
- Author
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Phanitchat, Thipruethai, Zhao, B, Haque, Ubydul, Pientong, Chamsai, Ekalaksananan, Tipaya, Aromseree, Sirinart, Thaewnongiew, Kesorn, Fustec, Benedicte, Bangs, MJ, Alexander, Neal, and Overgaard, Hans Jørgen
- Published
- 2019
3. Malaria morbidity and mortality following introduction of a universal policy of artemisinin-based treatment for malaria in Papua, Indonesia: A longitudinal surveillance study
- Author
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von Seidlein, L, Kenangalem, E, Poespoprodjo, JR, Douglas, NM, Burdam, FH, Gdeumana, K, Chalfein, F, Prayoga, Thio, F, Devine, A, Marfurt, J, Waramori, G, Yeung, S, Noviyanti, R, Penttinen, P, Bangs, MJ, Sugiarto, P, Simpson, JA, Soenarto, Y, Anstey, NM, Price, RN, von Seidlein, L, Kenangalem, E, Poespoprodjo, JR, Douglas, NM, Burdam, FH, Gdeumana, K, Chalfein, F, Prayoga, Thio, F, Devine, A, Marfurt, J, Waramori, G, Yeung, S, Noviyanti, R, Penttinen, P, Bangs, MJ, Sugiarto, P, Simpson, JA, Soenarto, Y, Anstey, NM, and Price, RN
- Abstract
BACKGROUND: Malaria control activities can have a disproportionately greater impact on Plasmodium falciparum than on P. vivax in areas where both species are coendemic. We investigated temporal trends in malaria-related morbidity and mortality in Papua, Indonesia, before and after introduction of a universal, artemisinin-based antimalarial treatment strategy for all Plasmodium species. METHODS AND FINDINGS: A prospective, district-wide malariometric surveillance system was established in April 2004 to record all cases of malaria at community clinics and the regional hospital and maintained until December 2013. In March 2006, antimalarial treatment policy was changed to artemisinin combination therapy for uncomplicated malaria and intravenous artesunate for severe malaria due to any Plasmodium species. Over the study period, a total of 418,238 patients presented to the surveillance facilities with malaria. The proportion of patients with malaria requiring admission to hospital fell from 26.9% (7,745/28,789) in the pre-policy change period (April 2004 to March 2006) to 14.0% (4,786/34,117) in the late transition period (April 2008 to December 2009), a difference of -12.9% (95% confidence interval [CI] -13.5% to -12.2%). There was a significant fall in the mortality of patients presenting to the hospital with P. falciparum malaria (0.53% [100/18,965] versus 0.32% [57/17,691]; difference = -0.21% [95% CI -0.34 to -0.07]) but not in patients with P. vivax malaria (0.28% [21/7,545] versus 0.23% [28/12,397]; difference = -0.05% [95% CI -0.20 to 0.09]). Between the same periods, the overall proportion of malaria due to P. vivax rose from 44.1% (30,444/69,098) to 53.3% (29,934/56,125) in the community clinics and from 32.4% (9,325/28,789) to 44.1% (15,035/34,117) at the hospital. After controlling for population growth and changes in treatment-seeking behaviour, the incidence of P. falciparum malaria fell from 511 to 249 per 1,000 person-years (py) (incidence rate ratio [IRR
- Published
- 2019
4. Age-specific prevalence of Plasmodium falciparum among six populations with limited histories of exposure to endemic malaria
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Ellen M. Andersen, Hasan Basri, Masbar S, Purnomo, P. R. Arbani, Harjosuwarno S, J K Baird, B Subianto, Bangs Mj, and Trevor R. Jones
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Adult ,Male ,Aging ,medicine.medical_specialty ,Protective immunity ,Adolescent ,PLASMODIUM FALCIPARUM PARASITEMIA ,Parasitemia ,Virology ,parasitic diseases ,Epidemiology ,Prevalence ,medicine ,Animals ,Humans ,Malaria, Falciparum ,Child ,Protozoal disease ,biology ,business.industry ,Age Factors ,Plasmodium falciparum ,biology.organism_classification ,medicine.disease ,Age specific ,Infectious Diseases ,Indonesia ,Child, Preschool ,Splenomegaly ,Immunology ,Female ,Parasitology ,business ,Malaria ,Demography - Abstract
The age-specific prevalence of Plasmodium falciparum parasitemia among residents of six villages in northeastern Irian Jaya, Indonesia, has been measured for a period of five years. All study subjects were transmigrants from Java living in Irian Jaya for three weeks to 72 months, depending upon the village and point of measurement. Fifteen separate estimates of prevalence were obtained from 4,554 Giemsa-stained thick blood films from 91 to 701 people (mean sample size = 304) among the six villages. The prevalence of parasitemia among people who had lived in Irian Jaya for less than one year did not decrease as a function of age, except in one village at eight months. In contrast, after 16 months to two years or more of residence, the prevalence of parasitemia decreased markedly with increasing age beyond 6–10 or 11–15 years. Social, behavioral, or entomologic characteristics of these populations did not explain the decreasing prevalence of parasitemia with age. An age-dependent naturally acquired protective immunity appeared to develop in all of these villages after 1–2 years of exposure to hyperendemic malaria.
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- 2016
5. Resistance to antimalarials by Plasmodium falciparum in Arso PIR, Irian Jaya, Indonesia
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Purnomo, Trevor R. Jones, J K Baird, Ritonga A, Bangs Mj, and Hasan Basri
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Male ,Sulfadoxine ,medicine.medical_treatment ,Plasmodium falciparum ,Drug Resistance ,Amodiaquine ,Pharmacology ,Antimalarials ,Chloroquine ,Virology ,medicine ,Animals ,Humans ,Quinine ,biology ,Mefloquine ,biology.organism_classification ,medicine.disease ,Malaria ,Drug Combinations ,Infectious Diseases ,Pyrimethamine ,Indonesia ,Immunology ,Parasitology ,Female ,medicine.drug - Abstract
Between 1987 and 1990, susceptibility of Plasmodium falciparum to chloroquine and to Fansidar was measured in vivo in 151 volunteers using the standard 7-day test. All volunteers lived in Arso PIR, Irian Jaya. A 25 mg/kg dose of chloroquine base was administered over a three-day period to 92 volunteers positive for P. falciparum rings (greater than 10 rings/200 white blood cells). Fifty volunteers (54%) showed results consistent with resistance. Twenty-nine were classified RII, and 21 RIII. In November 1989, a single curative dose of Fansidar was administered to 59 volunteers divided among three groups with 18 months, four years, and life-long exposure to endemic malaria. The proportion of volunteers in each group still positive for P. falciparum on day 7 of followup was 54%, 0%, and 14%, respectively. Thus, immune status profoundly effected clinically response to Fansidar. Standard in vitro microtests were also performed on parasites from 11 volunteers against chloroquine, amodiaquine, quinine, pyrimethamine/sulfadoxine, and and mefloquine. Nine of ten isolates showed in vitro growth consistent with resistance to chloroquine. Tests with other drugs showed few isolates with results considered indicative of susceptibility. Arso PIR has a severe drug resistance problem.
- Published
- 2016
6. Cultivation of sexually mature Brugia malayi in vitro
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Bangs Mj, J K Baird, W. A. Riberu, Soeroto Atmosoedjono, Purnomo, and S. Tirtokusumo
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Male ,Larva ,biology ,Third stage larvae ,fungi ,Zoology ,biology.organism_classification ,Brugia malayi ,In vitro ,Culture Media ,Infectious Diseases ,Fertility ,Virology ,parasitic diseases ,Immunology ,Brugia ,Sexual maturity ,Helminths ,Animals ,Humans ,Parasitology ,Female - Abstract
Sexually mature male and female Brugia malayi were developed from third stage larvae after 60 days in the in vitro culture system described by Franke and others in 1987 (Am J Trop Med Hyg 37: 370-375). Between 75 and 100 days in culture, many worms produced living microfilariae. Each gravid female produced 200-1,500 microfilariae/day.
- Published
- 2016
7. Predicting the geographical distributions of the macaque hosts and mosquito vectors of Plasmodium knowlesi malaria in forested and non-forested areas
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Moyes, CL, Shearer, FM, Huang, Z, Wiebe, A, Gibson, HS, Nijman, V, Mohd-Azlan, J, Brodie, JF, Malaivijitnond, S, Linkie, M, Samejima, H, O'Brien, TG, Trainor, CR, Hamada, Y, Giordano, AJ, Kinnaird, MF, Elyazar, IRF, Sinka, ME, Vythilingam, I, Bangs, MJ, Pigott, DM, Weiss, DJ, Golding, N, Hay, SI, Moyes, CL, Shearer, FM, Huang, Z, Wiebe, A, Gibson, HS, Nijman, V, Mohd-Azlan, J, Brodie, JF, Malaivijitnond, S, Linkie, M, Samejima, H, O'Brien, TG, Trainor, CR, Hamada, Y, Giordano, AJ, Kinnaird, MF, Elyazar, IRF, Sinka, ME, Vythilingam, I, Bangs, MJ, Pigott, DM, Weiss, DJ, Golding, N, and Hay, SI
- Abstract
BACKGROUND: Plasmodium knowlesi is a zoonotic pathogen, transmitted among macaques and to humans by anopheline mosquitoes. Information on P. knowlesi malaria is lacking in most regions so the first step to understand the geographical distribution of disease risk is to define the distributions of the reservoir and vector species. METHODS: We used macaque and mosquito species presence data, background data that captured sampling bias in the presence data, a boosted regression tree model and environmental datasets, including annual data for land classes, to predict the distributions of each vector and host species. We then compared the predicted distribution of each species with cover of each land class. RESULTS: Fine-scale distribution maps were generated for three macaque host species (Macaca fascicularis, M. nemestrina and M. leonina) and two mosquito vector complexes (the Dirus Complex and the Leucosphyrus Complex). The Leucosphyrus Complex was predicted to occur in areas with disturbed, but not intact, forest cover (> 60% tree cover) whereas the Dirus Complex was predicted to occur in areas with 10-100% tree cover as well as vegetation mosaics and cropland. Of the macaque species, M. nemestrina was mainly predicted to occur in forested areas whereas M. fascicularis was predicted to occur in vegetation mosaics, cropland, wetland and urban areas in addition to forested areas. CONCLUSIONS: The predicted M. fascicularis distribution encompassed a wide range of habitats where humans are found. This is of most significance in the northern part of its range where members of the Dirus Complex are the main P. knowlesi vectors because these mosquitoes were also predicted to occur in a wider range of habitats. Our results support the hypothesis that conversion of intact forest into disturbed forest (for example plantations or timber concessions), or the creation of vegetation mosaics, will increase the probability that members of the Leucosphyrus Complex occur at these locat
- Published
- 2016
8. The distribution and bionomics of anopheles malaria vector mosquitoes in Indonesia
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Elyazar, IR, Sinka, ME, Gething, PW, Tarmidzi, SN, Surya, A, Kusriastuti, R, Baird, JK, Hay, SI, and Bangs, MJ
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parasitic diseases - Abstract
Malaria remains one of the greatest human health burdens in Indonesia. Although Indonesia has a long and renowned history in the early research and discoveries of malaria and subsequently in the successful use of environmental control methods to combat the vector, much remains unknown about many of these mosquito species. There are also significant gaps in the existing knowledge on the transmission epidemiology of malaria, most notably in the highly malarious eastern half of the archipelago. These compound the difficulty of developing targeted and effective control measures. The sheer complexity and number of malaria vectors in the country are daunting. The difficult task of summarizing the available information for each species and/or species complex is compounded by the patchiness of the data: while relatively plentiful in one area or region, it can also be completely lacking in others. Compared to many other countries in the Oriental and Australasian biogeographical regions, only scant information on vector bionomics and response to chemical measures is available in Indonesia. That information is often either decades old, geographically patchy or completely lacking. Additionally, a large number of information sources are published in Dutch or Indonesian language and therefore less accessible. This review aims to present an updated overview of the known distribution and bionomics of the 20 confirmed malaria vector species or species complexes regarded as either primary or secondary (incidental) malaria vectors within Indonesia. This chapter is not an exhaustive review of each of these species. No attempt is made to specifically discuss or resolve the taxonomic record of listed species in this document, while recognizing the ever evolving revisions in the systematics of species groups and complexes. A review of past and current status of insecticide susceptibility of eight vector species of malaria is also provided.
- Published
- 2013
9. Demographic risk factors for severe and fatal vivax and falciparum malaria among hospital admissions in northeastern Indonesian Papua
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Barcus, MJ, Basri, H, Picarima, H, Manyakori, C, Elyazar, I, Bangs, MJ, Maguire, JD, and Baird, JK
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parasitic diseases - Abstract
Between January 1998 and December 2000, the Jayapura Provincial Public Hospital in northeastern Indonesian New Guinea (Papua) admitted 5,936 patients with a diagnosis of malaria. The microscopic diagnosis at admission was Plasmodium falciparum (3,976, 67%), Plasmodium vivax (1,135, 19%), Plasmodium malariae (8, < 1%), and mixed species infections (817, 14%). Approximately 9% (367) of patients were classified as having severe malaria (277 P. falciparum, 36 P. vivax, 53 mixed infections, and 1 P. malariae) and 88 died (79 P. falciparum/mixed infections and 9 P. vivax). Risk of fatal outcomes among severe malaria patients was indistinguishable between those with falciparum versus vivax malaria (OR = 0.89; P = 0.771). Compared with non-pregnant women, pregnant women showed no higher risk of severe malaria (P = 0.643) or death caused by severe malaria (P = 0.748). This study compares admissions per population (based on census data), parasitemia, morbidity, and mortality among children versus adults, pregnant versus non-pregnant women, and urban/suburban versus rural residents.
- Published
- 2007
10. Age-dependent impairment of IgG responses to glycosylphosphatidylinositol with equal exposure to Plasmodium falciparum among Javanese migrants to Papua, Indonesia
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Hudson Keenihan, SN, Ratiwayanto, S, Soebianto, S, Marwoto, H, Krishnegowda, G, Gowda, DC, Bangs, MJ, Fryauff, DJ, Richie, TL, Kumar, S, and Baird, JK
- Abstract
Immune responses directed at glycosylphosphatidylinositol (GPI) anchors of Plasmodium falciparum may offer protection against symptomatic malaria. To independently explore the effect of age on generation of the anti-GPI IgG response, we measured serum anti-GPI IgGs in a longitudinal cohort of migrant Javanese children (6-12 years old) and adults (> or = 20 years old) with equivalent numbers of exposures to P. falciparum in Papua, Indonesia. While the peak response in adults was achieved after a single infection, comparable responses in children required > or = 3-4 infections. Significantly fewer children (16%) than adults (41%) showed a high (optical density > 0.44) anti-GPI IgG response (odds ratio [OR] = 3.8, 95% confidence interval [CI] = 2.3-6.3, P < 0.0001), and adults were more likely to show a persistently high response (OR = 5.5, 95% CI = 1.0-56.8, P = 0.03). However, the minority of children showing a strong response were significantly less likely to experience symptoms with subsequent parasitemia compared with those with a weak response (OR = 4.0, 95% CI = 1.1-13.8, P = 0.02). This effect was not seen among high- and low-responding adults (OR = 1.2, 95% CI = 0.5-2.8, P = 0.60). Host age, independent of cumulative exposure, apparently represents a key determinant of the quantitative and qualitative nature of the IgG response to P. falciparum GPI.
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- 2003
11. Role of residual spraying for malaria control in Belize
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Roberts, Dr, Vanzie, E., Bangs, Mj, Grieco, Jp, Lenares, H., Hshieh, P., Rejmankova, E., Sylvie Manguin, Andre, Rg, and Polanco, J.
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MODELE MATHEMATIQUE ,ANALYSE DE REGRESSION ,INSECTICIDE CHIMIQUE ,METHODE DE LUTTE ,PALUDISME ,DDT - Published
- 2002
12. Malaria vaccine study site in Irian Jaya, Indonesia: Plasmodium falciparum incidence measurements and epidemiologic considerations in sample size estimation
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Hasan Basri, J K Baird, Annis Ba, Harjosuwarno S, Suriadi Gunawan, Peter D. Mcelroy, Bangs Mj, Purnomo, Stephen L. Hoffman, and Trevor R. Jones
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Adult ,Male ,Protozoan Vaccines ,Veterinary medicine ,Adolescent ,Plasmodium vivax ,Plasmodium falciparum ,law.invention ,law ,Virology ,parasitic diseases ,Anopheles ,medicine ,Malaria, Vivax ,Animals ,Humans ,Malaria, Falciparum ,Transients and Migrants ,biology ,Malaria vaccine ,Incidence (epidemiology) ,Incidence ,Middle Aged ,biology.organism_classification ,medicine.disease ,Insect Vectors ,Infectious Diseases ,Transmission (mechanics) ,Indonesia ,Population study ,Parasitology ,Seasons ,Malaria ,Follow-Up Studies - Abstract
Malaria epidemiologic and entomologic studies were performed during both the high transmission and low transmission seasons to characterize the Plasmodium falciparum malaria transmission at a proposed malaria vaccine trial site in Irian Jaya, Indonesia. The study population consisted of two subsets: native Irianese men with lifelong exposure to malaria and transmigrants who arrived from a nonmalarious area 2.5 years before the start of the study. All subjects received a radical cure for malaria and were then monitored weekly by blood film. Both P. falciparum malaria attack rates and incidence densities were calculated; transmigrants had a significantly higher rate (P = 0.003) than the Irianese during the low transmission season study (20-weeks long) but not during the high transmission season study (12-weeks long). Lack of exposure-induced immunity left the transmigrants at a minimum 17-25% greater relative risk of becoming parasitemic compared with the Irianese during the low transmission season study. During the high transmission season study, 50% of the transmigrants were P. falciparum positive by week 6 and 50% of the Irianese by week 9. During the low transmission season, 50% of the transmigrants were positive by week 10 and 43% of the Irianese were positive by week 17. Entomologic studies showed that Anopheles koliensis was the predominant vector (> 98% of anopheline catch). Entomologic inoculation rates for P. falciparum were 0.018 and 0.39 infective bites/person/night for the low and high transmission seasons, respectively. New P. vivax cases represented between 16% and 42% of all initial malaria cases.(ABSTRACT TRUNCATED AT 250 WORDS)
- Published
- 1994
13. Anopheles balabacensis (Diptera: Culicidae), a vector of Wuchereria kalimantani (Nematoda: Onchocercidae) in east Kalimantan (Borneo), Indonesia
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Soeroto Atmosoedjono, Bangs Mj, Purnomo, and Djoharti
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General Veterinary ,biology ,Wuchereria kalimantani ,Ecology ,Anopheles balabacensis ,Cercopithecidae ,Onchocercidae ,biology.organism_classification ,medicine.disease ,Filariasis ,Host-Parasite Interactions ,Insect Vectors ,Indonesia ,Insect Science ,Vector (epidemiology) ,Anopheles ,medicine ,Animals ,Humans ,Parasitology ,Female ,Wuchereria ,Ecology, Evolution, Behavior and Systematics - Published
- 1993
14. Cultivation of sexually mature Brugia malayi in vitro
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Riberu, WA, Atmosoedjono, S, Tirtokusumo, S, Bangs, MJ, and Baird, JK
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fungi ,parasitic diseases - Abstract
Sexually mature male and female Brugia malayi were developed from third stage larvae after 60 days in the in vitro culture system described by Franke and others in 1987 (Am J Trop Med Hyg 37: 370-375). Between 75 and 100 days in culture, many worms produced living microfilariae. Each gravid female produced 200-1,500 microfilariae/day.
- Published
- 1990
15. In vivo responses to antimalarials by Plasmodium falciparum and Plasmodium vivax from isolated Gag Island off northwest Irian Jaya, Indonesia
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Bangs Mj, Emiliana Tjitra, David J. Fryauff, I. Sumawinata, A Kadir, Thomas L. Richie, Purnomo, and G Ingkokusumo
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Adult ,Adolescent ,Sulfadoxine ,medicine.medical_treatment ,Plasmodium falciparum ,Plasmodium vivax ,Population ,Drug Resistance ,Parasitemia ,Antimalarials ,Age Distribution ,Chloroquine ,Virology ,parasitic diseases ,Malaria, Vivax ,Prevalence ,medicine ,Animals ,Humans ,Malaria, Falciparum ,Child ,education ,education.field_of_study ,biology ,Infant ,medicine.disease ,biology.organism_classification ,Drug Combinations ,Pyrimethamine ,Infectious Diseases ,Indonesia ,Child, Preschool ,Parasitology ,Malaria ,medicine.drug - Abstract
There is renewed interest in the rich nickel and cobalt deposits of Pulau Gag, an isolated but malarious island off the northwest coast of Irian Jaya. In preparation for an expanded workforce, an environmental assessment of malaria risk was made, focusing upon malaria prevalence in the small indigenous population, and the in vivo sensitivity of Plasmodium falciparum and P. vivax to chloroquine (CQ) and sulfadoxine/pyrimethamine (S/P), the respective first- and second-line drugs for uncomplicated malaria in Indonesia. During April-June 1997, mildly symptomatic or asymptomatic malaria infections were found in 24% of 456 native residents. Infections by P. falciparum accounted for 60% of the cases. Respective day 28 cure rates for CQ (10 mg base/kg on days 0 and 1; 5 mg/kg on day 2) in children and adults were 14% and 55% (P < 0.005). Type RII and RIII resistance characterized only 5% of the CQ failures. Re-treatment of 36 P. falciparum CQ treatment failures with S/P (25 mg/kg and 1.25 mg/kg, respectively) demonstrated rapid clearance and complete sensitivity during the 28-day follow-up period. More than 97% of the P. vivax malaria cases treated with CQ cleared parasitemia within 48 hr. Three cases of P. vivax malaria recurred between days 21 and 28, but against low drug levels in the blood. The low frequency of RII and RIII P. falciparum resistance to CQ, the complete sensitivity of this species to S/P, and the absence of CQ resistance by P. vivax are in contrast to in vivo and in vitro test results from sites on mainland Irian Jaya.
16. Rapid entomological assessment in eight high malaria endemic regencies in Papua Province revealed the presence of indoor and outdoor malaria transmissions.
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Rozi IE, Permana DH, Syahrani L, Asih PBS, Zubaidah S, Risandi R, Wangsamuda S, Dewayanti FK, Demetouw MR, Mabui S, Robaha MMF, Sumiwi ME, Bangs MJ, Lobo NF, Hawley WA, and Syafruddin D
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- Animals, Humans, Indonesia epidemiology, Larva, Endemic Diseases, Anopheles parasitology, Anopheles physiology, Malaria transmission, Malaria epidemiology, Malaria prevention & control, Mosquito Vectors parasitology, Mosquito Vectors physiology
- Abstract
Malaria in eastern Indonesia remains high despite significant reduction and elimination in other parts of the country. A rapid entomological assessment was conducted in eight high malaria endemic regencies of Papua Province, Indonesia, to expedite malaria elimination efforts in this region. This study aims to characterize specific, actionable endpoints toward understanding where and when malaria transmission is happening, where interventions may function best, and identify gaps in protection that result in continued transmission. The entomological assessment included identifying potential vectors through human landing catch (HLC), indoor morning and night resting collections, identification of larval sites through surveillance of water bodies, and vector incrimination toward understanding exposure to malaria transmission. Human landing catches (HLCs) and larval collections identified 10 Anopheles species, namely Anopheles koliensis, Anopheles punctulatus, Anopheles farauti, Anopheles hinesorum, Anopheles longirostris, Anopheles peditaeniatus, Anopheles tesselatus, Anopheles vagus, Anopheles subpictus and Anopheles kochi. The most common and abundant species found overall were An. koliensis and An. punctulatus, while An. farauti was found in large numbers in the coastal areas of Mimika and Sarmi Regencies. Vector incrimination on Anopheles collected from HLCs and night indoor resting demonstrated that An. koliensis and An. punctulatus carried Plasmodium in Keerom, Jayapura, and Sarmi Regencies. Analysis of HLCs for the most common species revealed that the An. koliensis and An. punctulatus, bite indoors and outdoors at equal rates, while An. farauti predominantly bite outdoors. Larval surveillance demonstrated that most water bodies in and surrounding residential areas contained Anopheles larvae. This study demonstrated indoor and outdoor exposure to mosquito bites and gaps in protection, enabling exposure to infectious bites in all regencies. This explains why current malaria control efforts focusing on indoor protection have failed to substantially reduce malaria incidence in the region. Optimization of insecticide-treated bed nets (ITNs), as well as installment of mosquito screens in houses, may further reduce indoor transmission. For outdoor transmission, the use of community-centric approaches to reduce or eliminate larval sources within and surrounding the village through the guidance of locally stationed entomologists, along with Social and Behavior Change mediated health education towards the local adoption of mosquito protection tools during outdoor activities, may reduce malaria transmission., (© 2024. The Author(s).)
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- 2024
- Full Text
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17. Impact of a spatial repellent intervention on Anopheles kdr insecticide resistance allele in Sumba, Indonesia.
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Syahrani L, Asih PBS, Bowolaksono A, Dwiranti A, Zubaidah S, Rozi IE, Permana DH, Bøgh C, Bangs MJ, Grieco JP, Achee NL, Lobo NF, and Syafruddin D
- Subjects
- Animals, Female, Alleles, Indonesia, Insecticide Resistance genetics, Permethrin, Anopheles genetics, Insecticides pharmacology, Cyclopropanes, Fluorobenzenes
- Abstract
Background: The emergence of insecticide resistance and outdoor transmission in malaria-endemic areas underlines the urgent need to develop innovative tools, such as spatial repellents (SR), that may circumvent this residual transmission. With limited options for effective insecticides, regular resistance monitoring is warranted for selecting and using appropriate tools. This study evaluates the pyrethroid knockdown resistance (kdr) allele before and after implementing a transfluthrin-based spatial repellent (SR) intervention in placebo-treated clusters., Methods: This study looks at the frequency distribution of the kdr allele in Sumba Island from June 2015 to August 2018. Insecticide susceptibility tests were carried out on female Anopheles sp. aged 3-5 days against permethrin 21.5 μg/ml, deltamethrin 12.5 μg/ml, and transfluthrin 10 μg/ml using CDC bottle assay. PCR sequencing of representative samples from adult mosquito collections and insecticide tests revealed the presence of kdr mutations (L1014F and L1014S) in the VGSC gene., Results: A total of 12 Anopheles species, Anopheles tesselatus, Anopheles. aconitus, Anopheles barbirostris, Anopheles kochi, Anopheles annularis, Anopheles maculatus, Anopheles sundaicus, Anopheles flavirostris, Anopheles balabacensis, Anopheles indefinitus, Anopheles subpictus, and Anopheles vagus were analysed. Anopheles vagus and An. sundaicus predominated in the larval populations. Susceptibility assays for all insecticides identified fully susceptible phenotypes in all species examined. Anopheles increasing frequency of kdr mutant alleles during the 3 year SR deployment was observed in both SR-treated and placebo areas, a statistically significant increase occurred in each arm. However, it is unclear how significant SR is in causing the increase in mutant alleles. The L1014S, knockdown resistance east type (kdr-e) allele was detected for the first time among the mosquito samples in this study. The L1014F, knockdown resistance west type (kdr-w) allele and heteroduplex form (wild-type-mutant) were found in almost all Anopheles species examined, including An. vagus, An. aconitus, An. subpictus, An. tesselatus, An. annularis, An. flavirostris and An. sundaicus., Conclusion: The presence of fully susceptible phenotypes over time, along with an increase in the frequency distribution of the L1014F/S mutations post-intervention, suggest drivers of resistance external to the study, including pyrethroid use in agriculture and long-lasting insecticidal nets (LLINs). However, this does not negate possible SR impacts that support resistance. More studies that enable the comprehension of possible SR-based drivers of resistance in mosquitoes need to be conducted., (© 2024. The Author(s).)
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- 2024
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18. Population structure and invasion history of Aedes aegypti (Diptera: Culicidae) in Southeast Asia and Australasia.
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Maynard AJ, Ambrose L, Bangs MJ, Ahmad R, Butafa C, and Beebe NW
- Abstract
The dengue mosquito, Aedes aegypti (Linnaeus, 1762), is a highly invasive and medically significant vector of dengue, yellow fever, chikungunya and Zika viruses, whose global spread can be attributed to increased globalization in the 15th through 20th century. Records of the invasion history of Ae. aegypti across Southeast Asia are sparse and there is little knowledge regarding the invasion routes that the species exploited to gain a foothold in the Indo-Pacific. Likewise, a broad and geographically thorough investigation of Ae. aegypti population genetics in the Indo-Pacific is lacking, despite this region being highly impacted by diseases transmitted by this species. We assess 11 nuclear microsatellites and mitochondrial COI sequences, coupled with widespread sampling through the Indo-Pacific region to characterise population structure at a broad geographic scale. We also perform a comprehensive literature search to collate documentation of the first known records of Ae. aegypti at various locations in the Indo-Pacific. We revealed additional spatial population genetic structure of Ae. aegypti in Southeast Asia, the Indo-Pacific and Australasia compared with previous studies and find differentiation between multiple Queensland and Torres Strait Islands populations. We also detected additional genetic breaks within Australia, Indonesia and Malaysia. Characterising the structure of previously unexplored populations through this region enhances the understanding of the population structure of Ae. aegypti in Australasia and Southeast Asia and may assist predictions of future mosquito movement, informing control strategies as well as assessing the risk of new invasion pathways., Competing Interests: Authors have no conflict of interest., (© 2023 The Authors. Evolutionary Applications published by John Wiley & Sons Ltd.)
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- 2023
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19. Correction: Scientific achievements and reflections after 20 years of vector biology and control research at the Pu Teuy mosquito field research station, Thailand.
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Sirisopa P, Sukkanon C, Bangs MJ, Nakasathien S, Hii J, Grieco JP, Achee NL, Manguin S, and Chareonviriyaphap T
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- 2023
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20. Comparison of Vector Trapping Methods for Outdoor Biting Malaria Vector Surveillance in Thailand and Vietnam.
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Ngoenklan R, Thanh Duong T, Duc Chinh V, Quang Thieu N, Hii J, Bangs MJ, Aum-Aung B, Suwonkerd W, and Chareonviriyaphap T
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- Humans, Animals, Mosquito Vectors, Thailand epidemiology, Vietnam, Mosquito Control methods, Anopheles, Malaria
- Abstract
The performances of the human-baited double net trap (HDNT) and the human-baited host decoy trap (HDT) methods were compared against the outdoor human landing catch (OHLC) method in Thailand and Vietnam. Two study sites were selected in each country: a rural village and a nearby forest setting. The three outdoor trap methods were rotated nightly between three set trapping positions, in a pre-assigned Latin square design. Volunteers were rotated following the trap rotation to avoid bias. The greatest number of adult mosquitoes was collected from the forest sites in both countries, showing Anopheles minimus (s.s.) Theobald (96.54%) and Anopheles dirus (s.s.) Peyton & Harrison (25.71%) as the primary malaria vectors in Thailand and Vietnam, respectively. At the Thai forest site, OHLC collected significantly more anopheline mosquitoes per trap night than HDNT and HDT, with mean ± standard error values of 14.17 ± 4.42, 4.83 ± 1.56, and 4.44 ± 1.45, respectively, whilst HDNT and HDT were significantly less productive at 0.34 times and 0.31 times, respectively, than OHLC in capturing anopheline mosquitoes. However, there were no significant differences among the three methods of trapping malaria vectors for the village site. At the Vietnamese forest site, HDNT achieved the highest performance in collecting Anopheline mosquitoes at 1.54 times compared to OHLC, but there was no significant difference between the two traps. The results suggested HDNT could be a possible alternative trap to OHLC in this area. Although HDT was less efficient at attracting Anopheline mosquitoes, it was highly efficient at trapping culicine mosquitoes., (© The Author(s) 2022. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2022
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21. Human behavior determinants of exposure to Anopheles vectors of malaria in Sumba, Indonesia.
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Rozi IE, Syahrani L, Permana DH, Asih PBS, Hidayati APN, Kosasih S, Dewayanti FK, Risandi R, Zubaidah S, Bangs MJ, Bøgh C, Grieco JP, Baus JE, Eugenio E, Monroe A, Liu F, Achee NL, Syafruddin D, and Lobo NF
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- Humans, Animals, Mosquito Control, Indonesia epidemiology, Mosquito Vectors, Feeding Behavior, Anopheles, Malaria epidemiology, Malaria prevention & control, Insect Bites and Stings epidemiology, Insect Repellents pharmacology, Insecticides pharmacology
- Abstract
Malaria vector control interventions in Sumba, Indonesia, have not been able to eliminate malaria. Human drivers of exposure to Anopheles bites were investigated as part of a larger clinical trial evaluating the impact of a spatial repellent product on malaria incidence. Human behavioral observations (HBOs) evaluating temporal and spatial presence, sleeping behaviors, and insecticide treated net (ITN) use, were collected parallel to entomological collections-indoor and outdoor human landing catches (HLCs), and house hold surveys. Data demonstrates that mosquito access to humans, enabled by structurally open houses, is evident by the similar entomological landing rates both inside and outside households. The presence of animals inside houses was associated with increased mosquito entry-however, the number of humans present inside houses was not related to increased mosquito landing. Analyzing mosquito landing rates with human behavior data enables the spatial and temporal estimation of exposure to Anopheles bites, accounting for intervention (ITN) presence and usage. Human behavior adjusted exposure to Anopheles bites was found to be highest in the early in the evening, but continued at lower levels throughout the night. Over the night, most exposure (53%) occurred when people were indoors and not under the protection of nets (asleep or awake) followed by exposure outside (44%). Characterized gaps in protection are outdoor exposure as well as exposure indoors-when awake, and when asleep and not using ITNs. Interestingly, in the primary trial, even though there was not a significant impact of the spatial repellent on vector biting rates by themselves (16%), when factoring in human behavior, there was approximately 28% less exposure in the intervention arm than in the placebo arm. The treated arm had less human behavior adjusted bites in all spaces evaluated though there was proportionally higher exposure indoors. This analysis points to the importance of using HBOs both towards understanding gaps in protection as well as how interventions are evaluated. To mitigate ongoing transmission, understanding context specific spatial and temporal exposure based on the interactions of vectors, humans and interventions would be vital for a directed evidence-based control or elimination strategy., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2022 Rozi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
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- 2022
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22. Impact of a spatial repellent product on Anopheles and non-Anopheles mosquitoes in Sumba, Indonesia.
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Permana DH, Zubaidah S, Syahrani L, Asih PBS, Syafruddin D, Rozi IE, Hidayati APN, Kosasih S, Dewayanti FK, Rachmawati N, Risandi R, Bangs MJ, Bøgh C, Davidson JR, Hendershot AL, Burton TA, Grieco JP, Eugenio EC, Liu F, Achee NL, and Lobo NF
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- Animals, Humans, Indonesia, Mosquito Control methods, Mosquito Vectors, Aedes, Anopheles, Culex, Insect Repellents pharmacology, Malaria prevention & control
- Abstract
Background: The East Nusa Tenggara province, Indonesia, contributed to 5% of malaria cases nationally in 2020, with other mosquito-borne diseases, such as dengue and filariasis also being endemic. Monitoring of spatial and temporal vector species compositions and bionomic traits is an efficient method for generating evidence towards intervention strategy optimization and meeting disease elimination goals., Methods: The impact of a spatial repellent (SR) on human biting mosquitoes was evaluated as part of a parent cluster-randomized, double-blinded, placebo-controlled trial, in Sumba, East Nusa Tenggara. A 10-month (June 2015-March 2016) baseline study was followed by a 24-month intervention period (April 2016 to April 2018)-where half the clusters were randomly assigned either a passive transfluthrin emanator or a placebo control., Results: Human-landing mosquito catches documented a reduction in landing rates related to the SR. Overall, there was a 16.4% reduction (21% indoors, and 11.3% outdoors) in human biting rates (HBR) for Anopheles. For Aedes, there was a 44.3% HBR reduction indoors and a 35.6% reduction outdoors. This reduction was 38.3% indoors and 39.1% outdoors for Armigeres, and 36.0% indoors and 32.3% outdoors for Culex species. Intervention impacts on the HBRs were not significant and are attributed to large inter-household and inter cluster variation. Anopheles flavirostris, Anopheles balabacensis and Anopheles maculatus individually impacted the overall malaria infections hazard rate with statistically significance. Though there was SR-based protection against malaria for all Anopheles species (except Anopheles sundaicus), only five (Anopheles aconitus, Anopheles kochi, Anopheles tessellatus, An. maculatus and An. sundaicus) demonstrated statistical significance. The SR numerically reduced Anopheles parity rates indoors and outdoors when compared to the placebo., Conclusion: Evidence demonstrating that Anopheles vectors bite both indoors and outdoors indicates that currently implemented indoor-based vector control tools may not be sufficient to eliminate malaria. The documented impact of the SR intervention on Aedes, Armigeres and Culex species points to its importance in combatting other vector borne diseases. Studies to determine the impact of spatial repellents on other mosquito-borne diseases is recommended., (© 2022. The Author(s).)
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- 2022
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23. An inventory of human night-biting mosquitoes and their bionomics in Sumba, Indonesia.
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Syahrani L, Permana DH, Syafruddin D, Zubaidah S, Asih PBS, Rozi IE, Hidayati APN, Kosasih S, Dewayanti FK, Rachmawati N, Risandi R, Bangs MJ, Bøgh C, Davidson J, Hendershot A, Burton T, Grieco JP, Achee NL, and Lobo NF
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- Animals, Ecology, Humans, Indonesia, Mosquito Vectors, Anopheles, Culex
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Mosquitoes are important vectors that transmit pathogens to human and other vertebrates. Each mosquito species has specific ecological requirements and bionomic traits that impact human exposure to mosquito bites, and hence disease transmission and vector control. A study of human biting mosquitoes and their bionomic characteristics was conducted in West Sumba and Southwest Sumba Districts, Nusa Tenggara Timur Province, Indonesia from May 2015 to April 2018. Biweekly human landing catches (HLC) of night biting mosquitoes both indoors and outdoors caught a total of 73,507 mosquito specimens (59.7% non-Anopheles, 40.3% Anopheles). A minimum of 22 Culicinae species belonging to four genera (Aedes, Armigeres, Culex, Mansonia), and 13 Anophelinae species were identified. Culex quinquefasciatus was the dominant Culicinae species, Anopheles aconitus was the principal Anopheles species inland, while An. sundaicus was dominant closer to the coast. The overall human biting rate (HBR) was 10.548 bites per person per night (bpn) indoors and 10.551 bpn outdoors. Mosquitoes biting rates were slightly higher indoors for all genera with the exception of Anopheles, where biting rates were slightly higher outdoors. Diurnal and crepuscular Aedes and Armigeres demonstrated declining biting rates throughout the night while Culex and Anopheles biting rates peaked before midnight and then declined. Both anopheline and non-anopheline populations did not have a significant association with temperature (p = 0.3 and 0.88 respectively), or rainfall (p = 0.13 and 0.57 respectively). The point distribution of HBR and seasonal variables did not have a linear correlation. Data demonstrated similar mosquito-human interactions occurring outdoors and indoors and during early parts of the night implying both indoor and outdoor disease transmission potential in the area-pointing to the need for interventions in both spaces. Integrated vector analysis frameworks may enable better surveillance, monitoring and evaluation strategies for multiple diseases., Competing Interests: The authors have declared that no competing interest exist. Author Michael J. Bangs was unable to confirm their authorship contributions. On their behalf, the corresponding author has reported their contributions to the best of their knowledge.
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- 2022
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24. Scientific achievements and reflections after 20 years of vector biology and control research at the Pu Teuy mosquito field research station, Thailand.
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Sirisopa P, Sukkanon C, Bangs MJ, Nakasathien S, Hii J, Grieco JP, Achee NL, Manguin S, and Chareonviriyaphap T
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- Animals, Entomology, Humans, Mosquito Control, Mosquito Vectors, Thailand, Anopheles, Insecticides
- Abstract
Additional vector control tools are needed to supplement current strategies to achieve malaria elimination and control of Aedes-borne diseases in many settings in Thailand and the Greater Mekong Sub-region. Within the next decade, the vector control community, Kasetsart University (KU), and the Ministry of Higher Education, Science, Research and Innovation must take full advantage of these tools that combine different active ingredients with different modes of action. Pu Teuy Mosquito Field Research Station (MFRS), Department of Entomology, Faculty of Agriculture, Kasetsart University (KU), Thailand was established in 2001 and has grown into a leading facility for performing high-quality vector biology and control studies and evaluation of public health insecticides that are operationally relevant. Several onsite mosquito research platforms have been established including experimental huts, a 40-m long semi-field screening enclosure, mosquito insectary, field-laboratory, and living quarters for students and researchers. Field research and assessments ranged from 'basic' investigations on mosquito biology, taxonomy and genetics to more 'applied' studies on responses of mosquitoes to insecticides including repellency, behavioural avoidance and toxicity. In the course of two decades, 51 peer-reviewed articles have been published, and 7 masters and 16 doctoral degrees in Entomology have been awarded to national and international students. Continued support of key national stakeholders will sustain MFRS as a Greater Mekong Subregion centre of excellence and a resource for both insecticide trials and entomological research., (© 2022. The Author(s).)
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- 2022
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25. Cananga odorata (Magnoliales: Annonaceae) Essential Oil Produces Significant Avoidance Behavior in Mosquitoes.
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Sukkanon C, Nararak J, Bangs MJ, and Chareonviriyaphap T
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- Aedes drug effects, Aedes physiology, Animals, Anopheles drug effects, Anopheles physiology, Culex drug effects, Insect Repellents pharmacology, Insecticides pharmacology, Mosquito Control methods, Avoidance Learning, Cananga chemistry, Culicidae drug effects, Culicidae physiology, Oils, Volatile pharmacology
- Abstract
Essential oil of Cananga odorata Hook. F. & Tomson is a source of insect repellent, but contact irritancy and noncontact repellency actions that stimulate insect's avoidance behavior (escape away from chemical source after direct physical contact or without making physical contact, respectively) have not been investigated. Therefore, an excito-repellency test chamber was used for measuring avoidance behavior of four insectary-reared mosquito species (Diptera: Culicidae) that escape from esposure to four concentrations (0.5, 1.0, 2.5, and 5.0% v/v) of C. odorata oil. The oil strongly repelled both Culex quinquefasciatus Say (85-97% escape) and Anopheles minimus Theobald (97-99%) at high concentrations (2.5-5.0%). For Anopheles dirus Peyton & Harrison and Aedes aegypti (L.), highest repellency (64 and 39% escape, respectively) was demonstrated at 2.5% concentration. For contact irritancy, the oil produced relatively high percent escape found in Cx. quinquefasciatus (90-100% escape) and An. minimus (83-100%). Whereas moderate contact irritancy was observed against An. dirus (40-50% escape) and Ae. aegypti (51-59%). The percent escape was then adjusted with repellency to estimate the effect of contact irritancy alone. We found that highest contact irritancy was presented at 0.5% concentration against An. minimus (67% escape). Knockdown and toxic actions were only found in Anopheles mosquitoes at 5.0% concentration. The results revealed that An. minimus and Cx. quinquefasciatus were more prone to be repelled by C. odorata oil. Detailed analysis of oil identified primary compounds as methyl benzoate (14.6%), α-gurjunene (12.8%), p-methyl-anisole (11.3%), and benzyl acetate (9.9%). Further investigations are needed to assess excito-repellency actions of these compounds alone or in combination., (© The Author(s) 2021. Published by Oxford University Press on behalf of Entomological Society of America.All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2022
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26. Semi-field evaluation of novel chemical lures for Aedes aegypti, Culex quinquefasciatus, and Anopheles minimus (Diptera: Culicidae) in Thailand.
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Kim DY, Leepasert T, Bangs MJ, and Chareonviriyaphap T
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- Aedes radiation effects, Animals, Anopheles radiation effects, Culex radiation effects, Female, Humans, Lactic Acid chemistry, Male, Mosquito Vectors radiation effects, Ultraviolet Rays, Aedes drug effects, Anopheles drug effects, Culex drug effects, Lactic Acid pharmacology, Mosquito Vectors drug effects
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Background: Entomological surveillance is an important means of assessing the efficacy of insect vector management programs and estimating disease transmission thresholds. Among baited traps, Biogents' BG-Sentinel (BGS) trap baited with BG-Lure is considered to have the most similar outcome to, and be a possible replacement for, human-landing catches for the epidemiologically relevant monitoring of adult Aedes aegypti and Culex quinquefasciatus. In contrast to the BGS trap, the Black Hole ultraviolet (UV) light trap, which is widely used to catch nocturnal flying insects, is not baited with synthetic human odor-mimicking lures., Methods: We evaluated the L-lactic acid-based Kasetsart University (KU)-lures nos. 1-6 as novel candidate chemical lures for the diurnal species Ae. aegypti and the nocturnal species Cx. quinquefasciatus using two commercial traps (the BGS trap and the Black Hole UV light trap) in a semi-field screen (SFS) house. Firstly, we optimized the dose of each KU-lure in an SFS house (140 m
3 ). Secondly, six different candidate KU-lures were screened by comparing their percent attraction using a single discriminating dose (0.5 g). Finally, we evaluated the synergism of the KU-lures selected in this way with commercially available traps., Results: BGS traps baited with KU-lure no. 1 exhibited the greatest percent attraction for Ae. aegypti (29.5% ± 14.3%), whereas those baited with KU-lure no. 6 most strongly attracted Cx. quinquefasciatus (33.3% ± 10.7%). Interestingly, BGS traps treated with 10 g BG-Lure did not significantly attract more Ae. aegypti or Cx. quinquefasciatus than the untreated BGS traps. CO2 at a flow rate of 250 ml/min most strongly attracted both Ae. aegypti and Cx. quinquefasciatus (42.2% ± 14.2% and 75.1% ± 16.9%, respectively). BGS and Black Hole UV light traps with KU-lure no. 6 exhibited a stronger attraction for Cx. quinquefasciatus than untreated traps, and the percent attraction did not differ between the treated traps., Conclusions: Synergistic effects of KU-lures nos. 1 and 6 with the mosquito traps were demonstrated for both the diurnal and nocturnal species in the SFS house assays. However, further studies are urgently needed for the development of species-specific lures to increase trap efficacy in the field for local vector mosquitoes in Thailand., (© 2021. The Author(s).)- Published
- 2021
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27. Effect of Different Wall Surface Coverage With Deltamethrin-Treated Netting on the Reduction of Indoor-Biting Anopheles Mosquitoes (Diptera: Culicidae).
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Tainchum K, Bangs MJ, Sathantriphop S, and Chareonviriyaphap T
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- Animals, Female, Thailand, Culicidae, Insect Bites and Stings prevention & control, Insecticides, Mosquito Control instrumentation, Mosquito Nets statistics & numerical data, Nitriles, Pyrethrins
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Indoor residual spray with deltamethrin remains the most common tool for reducing malaria transmission in Thailand. Deltamethrin is commonly used to spray the entire inner surfaces of the walls to prevent mosquitoes from resting. This study compared the mosquito landing responses on humans inside three experimental huts treated with deltamethrin at three different extents of wall coverage (25%, 50%, and full coverage), with one clean/untreated hut serving as a control. There were no significant differences between the numbers of Anopheles mosquitoes landing in the 50% and full coverage huts, whereas, in comparison to both of these, there was a significantly greater number landing in the 25% coverage hut. This study demonstrates that varying the percent coverage of indoor surfaces with deltamethrin-treated netting influences the blood-feeding success of wild Anopheles, and our findings suggest that it may be possible to reduce the extent of insecticide surface treatment while maintaining equivalent mosquito avoidance action to that seen in fully treated structures., (© The Author(s) 2021. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2021
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28. Time of Test Periods Influence the Behavioral Responses of Anopheles minimus and Anopheles dirus (Diptera: Culicidae) to DEET.
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Tisgratog R, Sukkanon C, Sugiharto VA, Bangs MJ, and Chareonviriyaphap T
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Information on factors influencing the behavioral responses of mosquitoes to repellents is lacking and poorly understood, especially in the Anopheles species, night-biting mosquitoes. Our goal was to investigate the impact of different time periods on circadian activity and behavioral responses of two malaria vectors, Anopheles minimus and An. dirus , to 5% DEET using an excito-repellency test system. Each mosquito species was exposed to the repellent during the daytime (06.00-18.00) and nighttime (18.00-06.00), and time of observation was further divided into four 3-h intervals. Significant escape responses were observed between daytime and nighttime for An. minimus in both noncontact and contact tests. An. dirus showed statistical differences in contact irritancy escape response, whereas no significant difference was found in noncontact repellency tests. Both mosquito species showed more significantly higher escape responses when exposed to DEET during the afternoon and late in the night. This finding indicates that the time of testing may affect the behavioral responses of mosquitoes to repellents, especially in An. minimus and An. dirus. A better understanding of nocturnally active mosquito behavioral responses spanning from dusk to dawn would assist in optimizing product development, screening, and effective evaluation.
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- 2021
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29. Dengue virus in humans and mosquitoes and their molecular characteristics in northeastern Thailand 2016-2018.
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Nonyong P, Ekalaksananan T, Phanthanawiboon S, Aromseree S, Phadungsombat J, Nakayama EE, Shioda T, Sawaswong V, Payungporn S, Thaewnongiew K, Overgaard HJ, Bangs MJ, Alexander N, and Pientong C
- Subjects
- Adolescent, Adult, Aged, Animals, Case-Control Studies, Child, Child, Preschool, Culicidae, Epidemics, Female, Genotype, Geography, Humans, Infant, Infant, Newborn, Likelihood Functions, Male, Middle Aged, Phylogeny, Polymerase Chain Reaction, Prospective Studies, Thailand epidemiology, Young Adult, Dengue transmission, Dengue Virus genetics
- Abstract
Dengue is hyperendemic in most Southeast Asian countries including Thailand, where all four dengue virus serotypes (DENV-1 to -4) have circulated over different periods and regions. Despite dengue cases being annually reported in all regions of Thailand, there is limited data on the relationship of epidemic DENV infection between humans and mosquitoes, and about the dynamics of DENV during outbreaks in the northeastern region. The present study was conducted in this region to investigate the molecular epidemiology of DENV and explore the relationships of DENV infection in humans and in mosquitoes during 2016-2018. A total of 292 dengue suspected patients from 11 hospitals and 902 individual mosquitoes (at patient's houses and neighboring houses) were recruited and investigated for DENV serotypes infection using PCR. A total of 103 patients and 149 individual mosquitoes were DENV -positive. Among patients, the predominant DENV serotypes in 2016 and 2018 were DENV-4 (74%) and DENV-3 (53%) respectively, whereas in 2017, DENV-1, -3 and -4 had similar prevalence (38%). Additionally, only 19% of DENV infections in humans and mosquitoes at surrounding houses were serotypically matched, while 81% of infections were serotypically mismatched, suggesting that mosquitoes outside the residence may be an important factor of endemic dengue transmission. Phylogenetic analyses based on envelope gene sequences showed the genotype I of both DENV-1 and DENV-4, and co-circulation of the Cosmopolitan and Asian I genotypes of DENV-2. These strains were closely related to concurrent strains in other parts of Thailand and also similar to strains in previous epidemiological profiles in Thailand and elsewhere in Southeast Asia. These findings highlight genomic data of DENV in this region and suggest that people's movement in urban environments may result in mosquitoes far away from the residential area being key determinants of DENV epidemic dynamics., Competing Interests: The authors declare no competing interests exist.
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- 2021
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30. Transmitted Light as Attractant with Mechanical Traps for Collecting Nocturnal Mosquitoes in Urban Bangkok, Thailand.
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Saeung M, Jhaiaun P, Bangs MJ, Ngoen-Klan R, and Chareonviriyaphap T
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- Animals, Humans, Light, Mosquito Control, Thailand, Aedes, Anopheles, Culex
- Abstract
Mosquito surveillance is the cornerstone for determining abundance, species diversity, pathogen infection rates, and temporal and spatial distribution of different life stages in an area. Various methods are available for assessing adult mosquito populations, including mechanical trap devices using different forms of attractant cues (chemical and visual) to lure mosquitoes to the trap. So-called "light traps" use various electromagnetic wavelengths to produce a variety of visible spectral colors to attract adult mosquitoes. However, this type of trapping technology has not been widely used in Thailand. This study compared the efficacy of 4 light-emitting diodes (LEDs) (blue, green, yellow, and red) and 2 fluorescent (ultraviolet [UV] and white) lights for collecting mosquitoes in urban Bangkok. Using a Latin square experimental design, 6 light traps equipped with different lights were rotated between 6 trap site locations within the Kasetsart University (KU) campus. Each location received 6 replicate collections (6 consecutive trap-nights represented 1 replicate) over 36 collection nights for a total of 216 trap-nights. Traps were operated simultaneously (1800 to 0600 h), with captured mosquitoes removed at 3-h intervals. In total, 2,387 mosquitoes consisting of 11 species across 5 genera (Aedes, Anopheles, Armigeres, Culex, and Mansonia) were captured. Collectively, Culex species represented the predominant group sampled (2,252; 94.4%). The UV light source captured 1,544 (64.7%) of the total mosquitoes collected, followed by white 389 (16.3%), with the 4 LED sources collecting between 6.8% (blue) and 1.9% (yellow). Traps equipped with UV light were clearly the most effective for capturing nocturnally active mosquito species on the KU campus., (Copyright © 2021 by The American Mosquito Control Association, Inc.)
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- 2021
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31. Variable residual activity of K-Othrine® PolyZone and Actellic® 300 CS in semi-field and natural conditions in the Democratic Republic of the Congo.
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Ngwej LM, Mashat EM, Mukeng CK, Mundongo HT, Malonga FK, Kashala JK, and Bangs MJ
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- Animals, Democratic Republic of the Congo, Female, Housing, Malaria prevention & control, Anopheles, Insecticides, Mosquito Control, Mosquito Vectors, Nitriles, Organothiophosphorus Compounds, Pyrethrins
- Abstract
Background: Indoor Residual Spray (IRS) against vector mosquitoes is a primary means for combating malaria transmission. To combat increased patterns of resistance to chemicals against mosquito vectors, alternative candidate insecticide formulations should be screened. With mortality as the primary endpoint, the persistence of residual efficacy of a polymer-enhanced pyrethroid suspension concentrate containing deltamethrin (K-Othrine® PolyZone-KOPZ) applied at 25 mg active ingredient (ai)/m
2 was compared with a microencapsulated organophosphate suspension formulation of pirimiphos-methyl (Actellic® 300CS-ACS) applied at 1 g ai/m2 ., Methods: Following standard spray application, periodic contact bioassays were conducted for at least 38 weeks on four types of wall surfaces (unbaked clay, baked clay, cement, and painted cement) sprayed with either KOPZ or ACS in simulated semi-field conditions. Similarly, two types of existing walls in occupied houses (painted cement and baked clay) were sprayed and examined. A colonized strain of female Anopheles arabiensis mosquitoes were exposed to treated or untreated surfaces (controls) for 30 min. For each wall surface test period, 40 treatment mosquitoes (4 cones × 10) in semi-field and 90 (9 cones × 10) in 'natural' house conditions were used per wall. 30 mosquitoes (3 cones × 10) on a matching unsprayed surface served as the control. Insecticide, wall material, and sprayed location on wall (in houses) were compared by final mortality at 24 h., Results: Insecticide, wall material, and sprayed location on wall surface produced significant difference for mean final mortality over time. In semi-field conditions, KOPZ produced a 72% mean mortality over a 38-week period, while ACS gave 65% (p < 0.001). Painted cement wall performed better than other wall surfaces throughout the study period (73% mean mortality). In the two occupied houses, KOPZ provided a mean mortality of 88%, significantly higher than ACS (p < 0.001). KOPZ provided an effective residual life (≥ 80% mortality) between 7.3 and 14 weeks on experimental walls and between 18.3 and 47.2 weeks in houses, while ACS persisted between 3 and 7.6 weeks under semi-field conditions and between 7.1 and 17.3 weeks in houses. Household painted cement walls provided a longer effective residual activity compared to baked clay for both formulations. Greater mortality was recorded at the top and middle sections of sprayed wall compared to the bottom portion near the floor., Conclusion: KOPZ provided longer residual activity on all surfaces compared to ACS. Painted cement walls provided better residual longevity for both insecticides compared to other surfaces. Insecticides also performed better in an occupied house environment compared to semi-field constructed walls. This study illustrates the importance of collecting field-based observations to determine appropriate product active ingredient formulations and timing for recurring IRS cycles., (© 2021. The Author(s).)- Published
- 2021
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32. Evaluation of Mosquito Attractant Candidates Using a High-Throughput Screening System for Aedes aegypti (L.) , Culex quinquefasciatus Say. and Anopheles minimus Theobald (Diptera: Culicidae).
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Kim DY, Leepasert T, Bangs MJ, and Chareonviriyaphap T
- Abstract
Several types of olfactometers have been used to evaluate mosquito responses to agents that mimic natural volatiles that repel or attract. The Y-tube olfactometer has been widely used to study repellents and attractants, while the high-throughput screening system assay has only been used to study repellents. Whether the high-throughput screening system assay is suitable for evaluating attractants is unknown. We evaluated the responses to four lactic-acid-based mixtures and two non-lactic-acid-based chemical lure candidates using the high-throughput screening system (HITSS) for three mosquito species (laboratory strains and field populations of both Aedes aegypti (L.) and Culex quinquefasciatus Say.; laboratory strain of Anopheles minimus Theobald) under laboratory-controlled conditions. HITSS assay results showed that KU-lure #1 elicited the greatest percent attraction for pyrethroid-resistant and -susceptible Ae. aegypti. KU-lure #6 elicited the strongest attractive response for pyrethroid-susceptible and -resistant Cx. quinquefasciatus and pyrethroid-susceptible An. minimus . The response to the lures from each species was independent of the pyrethroid susceptibility status ( Ae. aegypti , p = 0.825; Cx. quinquefasciatus , p = 0.056). However, a significant difference in attraction to KU-lure #6 was observed between diurnal and nocturnal mosquitoes ( Cx. quinquefasciatus vs. Ae. aegypti , p = 0.014; An. minimus vs. Ae. aegypti , p = 0.001). The laboratory-level HITSS assay effectively selects potential lure candidates. Because the host-seeking behavior differs between mosquito species, further studies are needed to develop species-specific attractants. Additional studies in semi-field screen houses using commercial traps are necessary to evaluate the accuracy of these laboratory assay results.
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- 2021
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33. Serological biomarker for assessing human exposure to Aedes mosquito bites during a randomized vector control intervention trial in northeastern Thailand.
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Fustec B, Phanitchat T, Aromseree S, Pientong C, Thaewnongiew K, Ekalaksananan T, Cerqueira D, Poinsignon A, Elguero E, Bangs MJ, Alexander N, Overgaard HJ, and Corbel V
- Subjects
- Aedes growth & development, Animals, Biomarkers blood, Dengue epidemiology, Dengue transmission, Dengue Virus isolation & purification, Enzyme-Linked Immunosorbent Assay, Female, Humans, Immunoglobulin G analysis, Insect Bites and Stings immunology, Male, Mosquito Vectors virology, Saliva immunology, Thailand epidemiology, Aedes physiology, Aedes virology, Insect Bites and Stings epidemiology
- Abstract
Background: Aedes mosquitoes are vectors for several major arboviruses of public health concern including dengue viruses. The relationships between Aedes infestation and disease transmission are complex wherein the epidemiological dynamics can be difficult to discern because of a lack of robust and sensitive indicators for predicting transmission risk. This study investigates the use of anti-Aedes saliva antibodies as a serological biomarker for Aedes mosquito bites to assess small scale variations in adult Aedes density and dengue virus (DENV) transmission risk in northeastern Thailand. Individual characteristics, behaviors/occupation and socio-demographics, climatic and epidemiological risk factors associated with human-mosquito exposure are also addressed., Methods: The study was conducted within a randomized clustered control trial in Roi Et and Khon Kaen provinces over a consecutive 19 months period. Thirty-six (36) clusters were selected, each of ten houses. Serological and entomological surveys were conducted in all houses every four months and monthly in three sentinel households per cluster between September 2017 and April 2019 for blood spot collections and recording concurrent immature and adult Aedes indices. Additionally, the human exposure to Aedes mosquito bites (i.e., Mosquito Exposure Index or MEI) was estimated by ELISA measuring levels of human antibody response to the specific Nterm-34 kDa salivary antigen. The relationships between the MEI, vector infestation indices (adult and immature stages) and vector DENV infection were evaluated using a two-level (house and individual levels) mixed model analysis with one-month lag autoregressive correlation., Results: There was a strong positive relationship between the MEI and adult Aedes (indoor and outdoor) density. Individuals from households with a medium mosquito density (mean difference: 0.091, p<0.001) and households with a high mosquito density (mean difference: 0.131, p<0.001) had higher MEI's compared to individuals from households without Aedes. On a similar trend, individuals from households with a low, medium or high indoor Aedes densities (mean difference: 0.021, p<0.007, 0.053, p<0.0001 and 0.037, p<0.0001 for low, medium and high levels of infestation, respectively) had higher MEI than individuals from houses without indoor Aedes. The MEI was driven by individual characteristics, such as gender, age and occupation/behaviors, and varied according to climatic, seasonal factors and vector control intervention (p<0.05). Nevertheless, the study did not demonstrate a clear correlation between MEI and the presence of DENV-infected Aedes., Conclusion: This study represents an important step toward the validation of the specific IgG response to the Aedes salivary peptide Nterm-34kDa as a proxy measure for Aedes infestation levels and human-mosquito exposure risk in a dengue endemic setting. The use of the IgG response to the Nterm-34 kDa peptide as a viable diagnostic tool for estimating dengue transmission requires further investigations and validation in other geographical and transmission settings., Competing Interests: The authors have declared that no competing interests exist.
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- 2021
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34. Residual Malaria Transmission in Select Countries of Asia-Pacific Region: Old Wine in a New Barrel.
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Hii J, Hustedt J, and Bangs MJ
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- Animals, Asia epidemiology, Disease Progression, Humans, Mosquito Control, Mosquito Vectors, Anopheles, Insecticide-Treated Bednets, Insecticides, Malaria epidemiology, Malaria prevention & control, Malaria transmission
- Abstract
Background: Despite substantial reductions in malaria burden and improvement in case management, malaria remains a major public health challenge in the Asia-Pacific region. Residual malaria transmission (RMT) is the fraction of total transmission that persists after achievement of full operational coverage with effective insecticide-treated bed nets (ITNs)/long-lasting insecticidal nets (LLINs) and/or indoor residual spray interventions. There is a critical need to standardize and share best practices for entomological, anthropological, and product development investigative protocols to meet the challenges of RMT and elimination goals., Methods: A systematic review was conducted to describe when and where RMT is occurring, while specifically targeting ownership and usage of ITN/LLINs, indoor residual spray application, insecticide susceptibility of vectors, and human and vector biting behavior, with a focus on nighttime activities., Results: Sixty-six publications from 1995 to present met the inclusion criteria for closer review. Associations between local vector control coverage and use with behaviors of human and mosquito vectors varied by locality and circumstance. Consequently, the magnitude of RMT is insufficiently studied and analyzed with sparse estimates of individual exposure in communities, insufficient or incomplete observations of ITN/LLIN use, and the local human population movement into and from high-risk areas., Conclusions: This review identified significant gaps or deficiencies that require urgent attention, namely, developing standardized procedures and methods to estimate risk exposure beyond the peridomestic setting, analytical approaches to measure key human-vector interactions, and seasonal location-specific agricultural or forest use calendars, and establishing the collection of longitudinal human and vector data close in time and location., (© World Health Organization, 2021. All rights reserved. The World Health Organization has granted the Publisher permission for the reproduction of this article.)
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- 2021
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35. Dose-Response Assay for Synthetic Mosquito (Diptera: Culicidae) Attractant Using a High-Throughput Screening System.
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Kim DY, Leepasert T, Bangs MJ, and Chareonviriyaphap T
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Natural volatile host cues play a critical role for mosquito orientation and locating a blood source for egg production. Similar olfactory activation responses have allowed the use and development of artificial chemical attractants to lure mosquitoes to trapping devices. Using a pre-formulated commercial product mixture of different attractant chemicals, a high-throughput screening system (HITSS) is used to screen varying doses of chemical required to activate behavioral responses. Two strains of Aedes aegypti (L.): permethrin-susceptible (USDA) and -resistant (Pu Teuy) phenotypes and one Culex quinquefasciatus Say. (NIH) laboratory strain were tested. Overall, mosquitoes showed repellency between 1.0 g and to 10.0 g dose of each compound. However, by progressively reducing the dose, Cx. quinquefasciatus showed a greater positive percent attraction (88.9%) at 0.025 g, whereas the USDA and Pu Teuy Ae. aegypti produced optimum attractant activation at 0.005 g (72.6% and 58.9%, respectively) without significant difference within species ( p > 0.05). In parallel control assays, Cx. quinquefasciatus was significantly attracted to 1 g of dry ice (carbon dioxide) (76%) more than Ae. aegypti (USDA) (12.2%). The HITSS was originally designed to measure three chemical actions to sublethal concentrations of chemicals by mosquitoes: toxicity and the two primary behavior avoidance responses (contact excitation and spatial repellency). These findings demonstrate that the HITSS assay, with only minor modifications, allows comparison screening of candidate compounds as potential attractants for anemotactic responses under laboratory-controlled conditions. Further investigations will be required to equate measurements obtained from controlled laboratory assays to more varied field conditions for attracting natural mosquito populations.
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- 2021
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36. Correction: Anopheles sundaicus complex and the presence of Anopheles epiroticus in Indonesia.
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Syafruddin D, Lestari YE, Permana DH, Asih PBS, St Laurent B, Zubaidah S, Rozi IE, Kosasih S, Shinta, Sukowati S, Hakim L, Haryanto E, Mangunwardoyo W, Bangs MJ, and Lobo NF
- Abstract
[This corrects the article DOI: 10.1371/journal.pntd.0008385.].
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- 2021
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37. Field Evaluation of a Spatial Repellent Emanation Vest for Personal Protection Against Outdoor Biting Mosquitoes.
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Sukkanon C, Tisgratog R, Muenworn V, Bangs MJ, Hii J, and Chareonviriyaphap T
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- Animals, Culicidae drug effects, Humans, Insect Bites and Stings, Malaria prevention & control, Malaria transmission, Mosquito Control, Mosquito Vectors drug effects, Thailand, Anopheles drug effects, Cyclopropanes pharmacology, Fluorobenzenes pharmacology, Insect Repellents pharmacology
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Exophilic vectors are an important contributor to residual malaria transmission. Wearable spatial repellents (SR) can potentially provide personal protection in early evening hours before people retire indoors. An SR prototype for passive delivery of transfluthrin (TFT) for protecting humans against nocturnal mosquitoes in Kanchanaburi, western Thailand, is evaluated. A plastic polyethylene terephthalate (PET) sheet (676 cm2) treated with 55-mg TFT (TFT-PET), attached to the back of short-sleeve vest worn by human collector, was evaluated under semifield and outdoor conditions. Field-caught, nonblood-fed female Anopheles minimus s.l. were released in a 40 m length, semifield screened enclosure. Two collectors positioned at opposite ends conducted 12-h human-landing collections (HLC). The outdoor experiment was conducted between treatments among four collectors at four equidistant positions who performed HLC. Both trials were conducted for 30 consecutive nights. TFT-PET provided 67% greater protection (P < 0.001) for 12 h compared with unprotected control, a threefold reduction in the attack. In outdoor trials, TFT-PET provided only 16% protection against An. harrisoni Harbach & Manguin (Diptera: Culicidae) compared with unprotected collector (P = 0.0213). The TFT-PET vest reduced nonanophelines landing by 1.4-fold compared with the PET control with a 29% protective efficacy. These findings suggest that TFT-PET had diminished protective efficacy in an open field environment. Nonetheless, the concept of a wearable TFT emanatory device has the potential for protecting against outdoor biting mosquitoes. Further development of portable SR tools is required, active ingredient selection and dose optimization, and more suitable device design and materials for advancing product feasibility., (© The Author(s) 2020. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2021
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38. Considerations for Human Blood-Feeding and Arthropod Exposure in Vector Biology Research: An Essential Tool for Investigations and Disease Control.
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Harrington LC, Foy BD, and Bangs MJ
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- Animals, Ethics Committees, Research, Humans, Research Personnel, Arthropod Vectors physiology, Arthropods physiology, Feeding Behavior physiology, Vector Borne Diseases blood, Vector Borne Diseases transmission
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Eventually there may be a broadly acceptable, even perfected, substitute for the human host requirement for direct feeding experiments by arthropods, most notably mosquitoes. However, for now, direct and indirect feeding on human volunteers is an important, if not essential, tool in vector biology research (VBR). This article builds on the foundational publication by Achee et al. (2015) covering considerations for the use of human participants in VBR pursuits. The authors introduced methods involving human participation in VBR, while detailing human-landing collections (catches) as a prime example. Benedict et al. (2018) continued this theme with an overview of human participation and considerations for research that involves release of mosquito vectors into the environment. In this study, we discuss another important aspect of human use in VBR activities: considerations addressing studies that require an arthropod to feed on a live human host. Using mosquito studies as our principal example, in this study, we discuss the tremendous importance and value of this approach to support and allow study of a wide variety of factors and interactions related to our understanding of vector-borne diseases and their control. This includes establishment of laboratory colonies for test populations, characterization of essential nutrients that contribute to mosquito fitness, characterization of blood-feeding (biting) behavior and pathogen transmission, parameterization for modeling transmission dynamics, evaluation of human host attraction and/or agents that repel, and the effectiveness of antivector or parasite therapeutic drug studies.
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- 2020
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39. The Role of the Private Sector in Supporting Malaria Control in Resource Development Settings.
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Jones RT, Tusting LS, Smith HMP, Segbaya S, Macdonald MB, Bangs MJ, and Logan JG
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- Developing Countries, Health Knowledge, Attitudes, Practice, Humans, Private Sector, Quality of Health Care, Socioeconomic Factors, Communicable Disease Control organization & administration, Malaria prevention & control
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Industrial operations of the private sector, such as extraction, agriculture, and construction, can bring large numbers of people into new settlement areas and cause environmental change that promotes the transmission of vector-borne diseases. Industry-related workers and communities unduly exposed to infection risk typically lack the knowledge and means to protect themselves. However, there is a strong business rationale for protecting local resident employees through integrated vector control programs, as well as an ethical responsibility to care for these individuals and the affected communities. We discuss the role and challenges of the private sector in developing malaria control programs, which can include extensive collaborations with the public sector that go on to form the basis of national vector control programs or more broadly support local healthcare systems., (© 2020 World Health Organization; licensee Oxford University Press USA.)
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- 2020
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40. Complex relationships between Aedes vectors, socio-economics and dengue transmission-Lessons learned from a case-control study in northeastern Thailand.
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Fustec B, Phanitchat T, Hoq MI, Aromseree S, Pientong C, Thaewnongiew K, Ekalaksananan T, Bangs MJ, Corbel V, Alexander N, and Overgaard HJ
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- Adolescent, Adult, Animals, Case-Control Studies, Child, Dengue epidemiology, Dengue virology, Family Characteristics, Female, Humans, Male, Risk Factors, Thailand epidemiology, Young Adult, Aedes, Dengue transmission, Mosquito Vectors virology
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Background/objectives: Dengue fever is an important public health concern in most tropical and subtropical countries, and its prevention and control rest on vector surveillance and control. However, many aspects of dengue epidemiology remain unclear; in particular, the relationship between Aedes vector abundance and dengue transmission risk. This study aims to identify entomological and immunological indices capable of discriminating between dengue case and control (non-case) houses, based on the assessment of candidate indices, as well as individual and household characteristics, as potential risk factors for acquiring dengue infection., Methods: This prospective, hospital-based, case-control study was conducted in northeastern Thailand between June 2016 and August 2019. Immature and adult stage Aedes were collected at the houses of case and control patients, recruited from district hospitals, and at patients' neighboring houses. Blood samples were tested by RDT and PCR to detect dengue cases, and were processed with the Nterm-34 kDa salivary peptide to measure the human immune response to Aedes bites. Socioeconomic status, and other individual and household characteristics were analyzed as potential risk factors for dengue., Results: Study findings showed complex relationships between entomological indices and dengue risk. The presence of DENV-infected Aedes at the patient house was associated with 4.2-fold higher odds of dengue. On the other hand, Aedes presence (irrespective of infectious status) in the patient's house was negatively associated with dengue. In addition, the human immune response to Aedes bites, was higher in control than in case patients and Aedes adult abundance and immature indices were higher in control than in case houses at the household and the neighboring level. Multivariable analysis showed that children aged 10-14 years old and those aged 15-25 years old had respectively 4.5-fold and 2.9-fold higher odds of dengue infection than those older than 25 years., Conclusion: DENV infection in female Aedes at the house level was positively associated with dengue infection, while adult Aedes presence in the household was negatively associated. This study highlights the potential benefit of monitoring dengue viruses in Aedes vectors. Our findings suggest that monitoring the presence of DENV-infected Aedes mosquitoes could be a better indicator of dengue risk than the traditional immature entomological indices., Competing Interests: The authors have declared that no competing interests exist.
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- 2020
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41. Interepidemic Detection of Chikungunya Virus Infection and Transmission in Northeastern Thailand.
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Le BCT, Ekalaksananan T, Thaewnongiew K, Phanthanawiboon S, Aromseree S, Phanitchat T, Chuerduangphui J, Suwannatrai AT, Alexander N, Overgaard HJ, Bangs MJ, and Pientong C
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- Adolescent, Adult, Aged, Animals, Chikungunya Fever transmission, Chikungunya Fever virology, Chikungunya virus genetics, Chikungunya virus isolation & purification, Child, Child, Preschool, Female, Humans, Infant, Male, Middle Aged, Phylogeny, Prospective Studies, Thailand epidemiology, Young Adult, Aedes virology, Antibodies, Viral blood, Chikungunya Fever epidemiology, Chikungunya virus immunology, Disease Outbreaks, Mosquito Vectors virology
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Chikungunya fever is a viral mosquito-borne, acute febrile illness associated with rash, joint pain, and occasionally prolonged polyarthritis. Chikungunya outbreaks have been reported worldwide including many provinces of Thailand. Although chikungunya virus (CHIKV) occurs in Thailand, details on its epidemiology are lacking compared with dengue, a common mosquito-borne disease in the country. Therefore, study on CHIKV and its epidemiology in both humans and mosquitoes is required to better understand its importance clinically and dynamics in community settings. So a prospective examination of virus circulation in human and mosquito populations in northeastern Thailand using serological and molecular methods, including the genetic characterization of the virus, was undertaken. The study was conducted among febrile patients in eight district hospitals in northeastern Thailand from June 2016 to October 2017. Using real-time PCR on the conserved region of nonstructural protein 1 gene, CHIKV was detected in eight (4.9%) of 161 plasma samples. Only one strain yielded a sequence of sufficient size allowing for phylogenetic analysis. In addition, anti-CHIKV IgM and IgG were detected in six (3.7%) and 17 (10.6%) patient plasma samples. The single sequenced sample belonged to the East/Central/South Africa (ECSA) genotype and was phylogenetically similar to the Indian Ocean sub-lineage. Adult Aedes mosquitoes were collected indoors and within a 100-m radius from the index case house and four neighboring houses. CHIKV was detected in two of 70 (2.9%) female Aedes aegypti mosquito pools. This study clearly demonstrated the presence and local transmission of the ECSA genotype of CHIKV in the northeastern region of Thailand.
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- 2020
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42. Behavioral responses to transfluthrin by Aedes aegypti, Anopheles minimus, Anopheles harrisoni, and Anopheles dirus (Diptera: Culicidae).
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Sukkanon C, Nararak J, Bangs MJ, Hii J, and Chareonviriyaphap T
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- Aedes drug effects, Aedes physiology, Animals, Anopheles drug effects, Anopheles physiology, Avoidance Learning, Dose-Response Relationship, Drug, Female, Mosquito Control methods, Mosquito Vectors physiology, Vector Borne Diseases prevention & control, Behavior, Animal drug effects, Cyclopropanes pharmacology, Fluorobenzenes pharmacology, Insect Repellents pharmacology, Mosquito Vectors drug effects, Volatile Organic Compounds pharmacology
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Airborne spatial repellency (SR) is characterized and distinguished from other chemical actions including contact locomotor excitation and toxicity. The use of volatile spatial repellents is a potential new intervention class for combatting mosquito-borne pathogen transmission; therefore, continuing investigations on the actions of these chemicals that modify mosquito host-seeking behavior (i.e., bite prevention) is needed. The objective of this study is to characterize the key behavioral avoidance actions of transfluthrin (TFT) to advance spatial repellent development into practical products. Behavioral avoidance responses were observed for adult laboratory strains of Aedes aegypti, Anopheles minimus and An. dirus, and two field populations of An. harrisoni and Ae. aegypti, respectively. Established TFT sublethal (LC50 and LC75), lethal concentrations (LC99) and discriminating concentrations (DCs) were selected corresponding to each mosquito test species. Spatial repellency and contact excitation ('irritancy') responses on adult mosquitoes to TFT were assessed using an excito-repellency assay system. At LC50, TFT exhibited strong avoidance with An. minimus (60.1% escape) and An. dirus (80% escape) laboratory strains, showing between 12 and 16x greater escape response than Ae. aegypti (5% escape). Repellency responses for field collected Ae. aegypti and An. harrisoni were 54.9 and 47.1% escape, respectively. After adjusting the initial contact escape response (a measure of combined irritancy and repellency) to estimate only escape due to contact, the LC50 and LC99 showed moderate escape irritancy with laboratory Ae. aegypti (41.4% escape) and no contact activity against the field population. Adjustment showed only weak contact activity (16.1% escape) in laboratory An. minimus at LC50. Spatial repellency is the predominant mode of action of TFT among colonized and field mosquitoes used in this study. Established baseline (susceptible) dose-response curves assist in optimizing SR products for mosquito control and pathogen transmission prevention., Competing Interests: The authors have declared that no competing interests exist.
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- 2020
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43. Susceptibility of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) to Temephos in Thailand and Surrounding Countries.
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Saeung M, Ngoen-Klan R, Thanispong K, Muenworn V, Bangs MJ, and Chareonviriyaphap T
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- Animals, Cambodia, Laos, Larva growth & development, Malaysia, Myanmar, Singapore, Species Specificity, Thailand, Aedes growth & development, Insecticide Resistance, Insecticides, Mosquito Vectors growth & development, Temefos
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Aedes-borne virus disease control relies on insecticides to interrupt transmission. Temephos remains a key chemical for control of immature stage Aedes in Thailand and much of Southeast Asia. However, repeated use of insecticides may result in selection for resistance in vector populations, thus compromising operational intervention. Herein, the phenotypic response to temephos by Aedes aegypti (L.) and Aedes albopictus (Skuse) collected in Thailand and surrounding countries is presented. Data from 345 collection sites are included: 283 from literature review (244 sites with Ae. aegypti, 21 with Ae. albopictus, and 18 having both species sampled), plus 62 locations with Ae. aegypti in Thailand conducted between 2014 and 2018. Susceptibility assays followed WHO guidelines using the recommended discriminating dose of temephos (0.012 mg/liter) against late third to early fourth instar Ae. aegypti. Findings revealed 34 locations with susceptible Ae. aegypti, 13 with suspected resistance, and 15 indicating resistance. Published data between 1999 and 2019 in Thailand found Ae. aegypti resistant in 73 of 206 collection sites, whereas 3 locations from 11 sampled with low-level resistant in Ae. albopictus. From surrounding countries conducting temephos assays (Cambodia, Lao PDR, Myanmar, Malaysia, and Singapore), resistance is present in Ae. aegypti and Ae. albopictus from 27 of 56 and 19 of 28 locations, respectively. Routine insecticide susceptibility monitoring should be an operational requirement in vector control programs. Given the wide distribution and apparent increase in temephos-resistance, alternative larvicidal compounds must be considered if chemical control is to remain a viable vector control strategy., (© The Author(s) 2020. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2020
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44. Behavioral Action of Deltamethrin and Cypermethrin in Pyrethroid-Resistant Aedes aegypti (Diptera: Culicidae): Implications for Control Strategies in Thailand.
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Sathantriphop S, Paeporn P, Ya-Umphan P, Mukkhun P, Thanispong K, Chansang C, Bangs MJ, Chareonviriyaphap T, and Tainchum K
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- Aedes physiology, Animals, Avoidance Learning drug effects, Behavior, Animal, Dose-Response Relationship, Drug, Female, Insect Repellents pharmacology, Locomotion drug effects, Mosquito Control, Thailand, Aedes drug effects, Insecticide Resistance, Insecticides pharmacology, Nitriles pharmacology, Pyrethrins pharmacology
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Contact irritant (locomotor excitation) and noncontact spatial repellent avoidance behavior to deltamethrin and cypermethrin at dosages 0.025, 0.05, and 0.1 g/m2 impregnated on papers were evaluated in the laboratory against deltamethrin- and cypermethrin-resistant field populations of female Aedes aegypti (L.) from Rayong and Chanthaburi Provinces, Thailand. Pyrethroid-resistant populations were compared with a susceptible laboratory strain (NIH-Thai) using an 'excito-repellency' (ER) test system. Both NIH-Thai and field mosquitoes had stronger contact irritancy responses compared to the relatively weak noncontact repellency effects. Contact assays with deltamethrin and cypermethrin at 0.1 g/m2 showed high escape rates for Rayong (80.1 and 83.4%, respectively) and Chanthaburi (84.6 and 73.1%, respectively) mosquitoes. Cypermethrin produced significantly different (P < 0.05) percent escape responses in contact tests between NIH-Thai and field mosquitoes. Only deltamethrin contact at 0.05 g/m2 produced a significant escape response (P < 0.001) between NIH-Thai and Rayong mosquitoes. These results suggest that there may not be an overall significant effect of background pyrethroid resistance on escape response, and the differences by comparisons may reflect inherent individual variation when using the ER bioassay system. The results show that pyrethroid resistance in Ae. aegypti does not appear to influence or reduce contact avoidance responses with the compounds tested. In particular, deltamethrin at 0.1 g/m2 was an effective contact irritant and toxic compound against pyrethroid-resistant populations of Ae. aegypti. Therefore, 0.1 g/m2 deltamethrin could be considered for residual applications of either fixed surfaces or materials (e.g., curtains) as a supplemental control measure against adult dengue vectors., (© The Author(s) 2020. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2020
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45. Anopheles sundaicus complex and the presence of Anopheles epiroticus in Indonesia.
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Syafruddin D, Lestari YE, Permana DH, Asih PBS, St Laurent B, Zubaidah S, Rozi IE, Kosasih S, Shinta, Sukowati S, Hakim L, Haryanto E, Mangunwardoyo W, Bangs MJ, and Lobo NF
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- Animals, Cytochromes b genetics, Demography, Electron Transport Complex IV genetics, Female, Humans, Indonesia, Phylogeny, Anopheles genetics, Malaria transmission, Mosquito Vectors
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Anopheles sundaicus s.l. is an important malaria vector primarily found in coastal landscapes of western and central Indonesia. The species complex has a wide geographical distribution in South and Southeast Asia and exhibits ecological and behavioural variability over its range. Studies on understanding the distribution of different members in the complex and their bionomics related to malaria transmission might be important guiding more effective vector intervention strategies. Female An. sundaicus s.l. were collected from seven provinces, 12 locations in Indonesia representing Sumatra: North Sumatra, Bangka-Belitung, South Lampung, and Bengkulu; in Java: West Java; and the Lesser Sunda Islands: West Nusa Tenggara and East Nusa Tenggara provinces. Sequencing of ribosomal DNA ITS2 gene fragments and two mitochondrial DNA gene markers, COI and cytb, enabled molecular identification of morphologically indistinguishable members of the complex. Findings allowed inference on the distribution of the An. sundaicus s.l. present in Indonesia and further illustrate the phylogenetic relationships of An. epiroticus within the complex. A total of 370 An. sundaicus s.l specimens were analysed for the ITS2 fragment. The ITS2 sequence alignment revealed two consistent species-specific point mutations, a T>C transition at base 479 and a G>T transversion at base 538 that differentiated five haplotypes: TG, CG, TT, CT, and TY. The TG haplotype matched published An. epiroticus-indicative sequences from Thailand, Vietnam and peninsular Malaysia. The previously described insertion event (base 603) was observed in all identified specimens. Analysis of the COI and cytb genes revealed no consistent nucleotide variations that could definitively distinguish An. epiroticus from other members in the Sundaicus Complex. The findings indicate and support the existence of An. epiroticus in North Sumatra and Bangka-Belitung archipelago. Further studies are recommended to determine the full distributional extent of the Sundaicus complex in Indonesia and investigate the role of these species in malaria transmission., Competing Interests: The authors have declared that no competing interests exist.
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- 2020
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46. Efficacy of a Spatial Repellent for Control of Malaria in Indonesia: A Cluster-Randomized Controlled Trial.
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Syafruddin D, Asih PBS, Rozi IE, Permana DH, Nur Hidayati AP, Syahrani L, Zubaidah S, Sidik D, Bangs MJ, Bøgh C, Liu F, Eugenio EC, Hendrickson J, Burton T, Baird JK, Collins F, Grieco JP, Lobo NF, and Achee NL
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- Child, Preschool, Double-Blind Method, Female, Humans, Indonesia, Infant, Insect Repellents, Male, Mosquito Control, Mosquito Vectors, Cyclopropanes administration & dosage, Fluorobenzenes administration & dosage, Housing, Insecticides administration & dosage, Malaria prevention & control
- Abstract
A cluster-randomized, double-blinded, placebo-controlled trial was conducted to estimate the protective efficacy (PE) of a spatial repellent (SR) against malaria infection in Sumba, Indonesia. Following radical cure in 1,341 children aged ≥ 6 months to ≤ 5 years in 24 clusters, households were given transfluthrin or placebo passive emanators (devices designed to release vaporized chemical). Monthly blood screening and biweekly human-landing mosquito catches were performed during a 10-month baseline (June 2015-March 2016) and a 24-month intervention period (April 2016-April 2018). Screening detected 164 first-time infections and an accumulative total of 459 infections in 667 subjects in placebo-control households, and 134 first-time and 253 accumulative total infections among 665 subjects in active intervention households. The 24-cluster protective effect of 27.7% and 31.3%, for time to first-event and overall (total new) infections, respectively, was not statistically significant. Purportedly, this was due in part to zero to low incidence in some clusters, undermining the ability to detect a protective effect. Subgroup analysis of 19 clusters where at least one infection occurred during baseline showed 33.3% ( P -value = 0.083) and 40.9% ( P -value = 0.0236, statistically significant at the one-sided 5% significance level) protective effect to first infection and overall infections, respectively. Among 12 moderate- to high-risk clusters, a statistically significant decrease in infection by intervention was detected (60% PE). Primary entomological analysis of impact was inconclusive. Although this study suggests SRs prevent malaria, additional evidence is required to demonstrate the product class provides an operationally feasible and effective means of reducing malaria transmission.
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- 2020
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47. Bacterial Microbiome in Wild-Caught Anopheles Mosquitoes in Western Thailand.
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Tainchum K, Dupont C, Chareonviriyaphap T, Jumas-Bilak E, Bangs MJ, and Manguin S
- Abstract
Among the complex microbial community living in the mosquito midgut, some bacteria (e.g., Enterobacter spp.) can deliver effector molecules with anti- Plasmodium effects suppressing the development of malaria parasites ( Plasmodium falciparum ) before the öokinete can penetrate the mosquito midgut epithelium. Despite knowledge of this phenomenon, only a few studies have defined the diversity of microbiota in wild-caught adult Anopheles species. The objective of this study was to analyze and compare the bacterial microbiota in different Anopheles species, including representatives of the primary malaria vectors in western Thailand. Wild female Anopheles species were sampled from malaria-endemic areas in Tak and Mae Hong Son provinces near the Thai-Myanmar border. Midgut/abdominal bacterial diversity was assessed by examining the 16S rRNA gene, V3 hypervariable region, using PCR-Temporal Temperature Gel Electrophoresis (PCR-TTGE) profiling and sequence analysis. A total of 24 bacterial genera were identified from eight Anopheles species. Five bacterial genera were newly reported in Anopheles mosquitoes ( Ferrimonas , Megasphaera , Pectobacterium , Shimwellia , and Trabulsiella ). Five genera, including Megasphaera , were detected exclusively in a single-malaria ( Plasmodium vivax ) infected Anopheles minimus and not observed in other non-infected mosquitoes. The use of PCR-TTGE provides the first characterization of the midgut bacterial microbiome present in wild adult Anopheles in Thailand. Evidence that microbiota might impact pathogen development (suppression) in Anopheles and thereby reduce the risk of pathogen transmission deserves more studies to describe the presence and better understand the biological role of bacteria in natural mosquito populations., (Copyright © 2020 Tainchum, Dupont, Chareonviriyaphap, Jumas-Bilak, Bangs and Manguin.)
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- 2020
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48. Excito-repellency Activity of Andrographis paniculata (Lamiales: Acanthaceae) Against Colonized Mosquitoes.
- Author
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Sukkanon C, Karpkird T, Saeung M, Leepasert T, Panthawong A, Suwonkerd W, Bangs MJ, and Chareonviriyaphap T
- Subjects
- Aedes, Animals, Anopheles, Culex, Female, Andrographis chemistry, Culicidae, Insect Repellents, Insecticides, Mosquito Control, Plant Extracts
- Abstract
Excito-repellency activity of plant extracts have been increasingly studied as mosquito repellents. In this study, the crude extract of Andrographis paniculata was evaluated for its noncontact repellency, contact excitation (irritancy + repellency), and knockdown/toxicity response against five colonized mosquitoes; Aedes aegypti (L.), Aedes albopictus (Skuse), Anopheles dirus Peyton & Harrison, Anopheles epiroticus Linton & Harbach, and Culex quinquefasciatus Say (Diptera: Culicidae) using an excito-repellency assay system under laboratory-controlled conditions. The escape responses were observed at four different concentrations (0.5-5.0% w/v) with A. paniculata showing strong spatial repellency against Ae. albopictus (96.7% escape) and Ae. aegypti (71.7% escape) at the 2.5% and 0.5% concentrations, respectively. At 0.5% and 5.0% concentrations, the greatest repellency was seen for An. dirus (48.2% escape) and Cx. quinquefasciatus (59.7% escape), respectively. Comparatively, low repellency action was observed against An. epiroticus (1.6-15.0% escape). Escape in contact assays (before adjustment) was generally less pronounced compared to noncontact spatial repellency, with Ae. albopictus showing highest percent escape (71.4% escape) in the contact assay at 1.0% concentration. After adjusting for spatial repellency, escape due to contact irritancy alone was either not present or an insignificant contribution to the overall avoidance response for all species. No knockdown or mortality at 24-h postexposure was observed in any trials. These findings indicate that the A. paniculata crude extract is more active against day-biting mosquitoes; however, this may be a reflection of the time of testing. This study demonstrates compelling evidence that A. paniculata extract performs primarily as a spatial repellent. Further investigations exploring the use A. paniculata as a potential active ingredient in repellent products are needed., (© The Author(s) 2019. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2020
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49. Discriminating Lethal Concentrations for Transfluthrin, a Volatile Pyrethroid Compound for Mosquito Control in Thailand.
- Author
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Sukkanon C, Bangs MJ, Nararak J, Hii J, and Chareonviriyaphap T
- Subjects
- Animals, Dose-Response Relationship, Drug, Insecticide Resistance, Thailand, Aedes, Anopheles, Cyclopropanes, Fluorobenzenes, Insecticides, Mosquito Control, Mosquito Vectors
- Abstract
Pyrethroids are commonly used to control malaria and dengue vectors in Thailand. The lack of specific lethal discriminating concentrations (DCs) for specific mosquito species has possibly compromised more accurate assessments of physiological susceptibility to various chemicals over time. Previous studies have established DCs of various residual pyrethroids against specific mosquitoes in Thailand. However, DCs for transfluthrin (TFT), a highly volatile pyrethroid compound, against mosquito vectors in Thailand has been lacking. The aim of this study was to determine the DCs and susceptibility baselines of TFT against pyrethroid-susceptible laboratory strains of Aedes aegypti , Anopheles minimus , and An. dirus using the World Health Organization adult susceptibility tube method. Final DCs of TFT of each species were determined based on doubling the 99% lethal concentration at the following percentages: Ae. aegypti (0.06824%), An. minimus (0.06382%), and An. dirus (0.01508%). Subsequently, the respective TFT DCs were used to test field-collected populations of Ae. aegypti , An. harrisoni (Minimus Complex species), and An. dirus. Anopheles harrisoni and An. dirus were found completely susceptible (100% mortality), whereas Ae. aegypti from Nonthaburi Province was resistant to TFT. The suitability of the testing system and procedures is discussed. Routine assessment of insecticide susceptibility should include pyrethroids with high-vapor-pressure characteristics for informing control programs and consumers of product and chemical effectiveness.
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- 2019
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50. Increased prevalence of obesity, diabetes mellitus and hypertension with associated risk factors in a mine-based workforce, Democratic Republic of Congo.
- Author
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Mawaw PM, Yav T, Mukuku O, Lukanka O, Kazadi PM, Tambwe D, Omba J, Kakoma JB, Bangs MJ, and Luboya ON
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- Adolescent, Adult, Cohort Studies, Cost of Illness, Democratic Republic of the Congo epidemiology, Female, Humans, Longitudinal Studies, Male, Middle Aged, Noncommunicable Diseases epidemiology, Occupational Health, Overweight epidemiology, Prevalence, Retrospective Studies, Risk Factors, Young Adult, Diabetes Mellitus epidemiology, Hypertension epidemiology, Mining, Obesity epidemiology
- Abstract
Introduction: The burden of non-communicable diseases (NCDs) is increasing rapidly in low- and middle-income countries, with the largest portion occurring in Africa. Results from earlier baseline measures on obesity, diabetes and hypertension (ODH) in the Tenke Fungurume Mining (TFM) workforce in 2010 showed high proportions of overweight, pre-diabetic and pre-hypertensive individuals, predicting an upward trend in the burden of ODH over time. The 2010-2015 longitudinal trends on ODH and related risk factors among the TFM workforce is presented herein, and projects the consequent burden of these diseases on the workforce by 2025 if an effective prevention program is not implemented., Methods: A longitudinal, retrospective cohort study with 3-time intervals was conducted using occupational health records collected on all employees and contractors who had a pre-employment or follow up medical checkups covering the period between January 2010 and December 2015. Repeated paired t tests measured changes in mean values of quantitative risk factors, while a chi-square test assessed changes in prevalence and categorical risk factors over time. A linear projection model was used to predict the consequent morbidity of ODH for the subsequent 10 years up to 2025., Results: Between 2010 and 2015, prevalence increased from 4.5% to 11.1% for obesity, 11.9% to 15.6% for diabetes, and 18.2% to 26.5% for hypertension. By 2025, provided no prevention program is implemented, prevalence is predicted to reach 25%, 24% and 42% respectively for obesity, diabetes and hypertension., Conclusion: Without implementation of a comprehensive NCD prevention plan, the burden of ODH and other NCDs is predicted to increase dramatically in the TFM workforce. Alone or combined, NCDs have the potential to dramatically increase operational costs while decreasing productivity over time., Competing Interests: The authors declare no competing interests., (© Paul Makan Mawaw et al.)
- Published
- 2019
- Full Text
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