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Study’s Novelty/Excerpt • This study introduces an approach to controlling Culex mosquito populations by utilizing metabolites and spore extracts of Aspergillus fumigatus, marking a departure from traditional chemical insecticides that often lead to resistance and environmental harm. • The research is significant in identifying specific bioactive compounds, such as 9-eicosene and squalene, through GC-MS analysis, which have shown 100% larvicidal efficacy at higher concentrations. • By highlighting the potential of fungal extracts as an eco-friendly alternative, this work opens new avenues for sustainable mosquito vector control strategies. Full Abstract Culex mosquito species are known to transmit diseases such as dengue fever, West Nile virus infection, malaria, lymphatic filariasis, and Japanese encephalitis. An estimated 120 million people suffer from mosquito-borne diseases across the globe. Repeated use of chemical insecticides has led to the emergence of insecticide resistance by Culex mosquito species, pollution of the environment, and harmful impacts on non-target organisms. The purpose of this study is to evaluate the larvicidal potential of metabolites and spore extracts of Aspergillus fumigatus against Culex mosquito. The fungal spore concentrations were ascertained after 5 days of fungal culture by optical density measurements. An equal amount of methanol and ethyl acetate was used to extract metabolites at four different test concentrations (10, 20, 30, and 40 mg/mL). The chemical constituents of the extracted metabolites were characterized using GC-MS and FTIR analyses. The protocols enshrined by WHO (2005) were followed in conducting the larvicidal bioassay, whereas the lethal concentrations (LC50 and LC90) were calculated by Probit analysis. The highest mortality rate (100%) was recorded at the highest concentration of metabolites extract (40 mg/mL) of Aspergillus fumigatus. Complete (100%) was recorded at spores concentration of 4.5× 108 CFU/ml. The major bioactive compounds revealed by the GC-MS analysis include 9-eicosene, (E)-, 1-octadecene, 3-eicosene, (E)-, oleic acid, 1-nonadecene, cis-vaccenic acid, octadec-9-enoic acid, andsqualene. The outcomes of this study showed that Aspergillus fumigatus metabolites and spores extract have the potential to control mosquito vectors. Hence, there is a need for large-scale production of bioactive components, as revealed by GC-MS analysis.

INTRODUCTION: Japanese encephalitis virus (JEV) is a flavivirus, is the main cause viral encephalitis, endemic in South-East Asia, and Western Pacific regions and has become a major public health problem worldwide. JEV is transmitted to humans through the bite of an infected mosquito, mainly Culex tritaeniorhynchus that breeds in flooded rice fields, marshes, standing water around planted fields. Reservoir hosts are Adreid birds (herons and egrets), and pigs serve as amplifier hosts. Though infections are usually asymptomatic, the symptomatic Japanese encephalitis has a case fatality rate as high as 30%. Permanent neurologic or psychiatric sequelae can occur in 30-50% of those with encephalitis. There is no antiviral drug available. Treatment is mainly supportive and symptomatic. Safe and effective vaccines are available to prevent Japanese encephalitis. This article reviews recent advancements in diagnostic methods, prophylactics as well as therapeutic options and challenges to combat this zoonotic emerging and remerging viral encephalitis. [ABSTRACT FROM AUTHOR]

Among emerging zoonotic pathogens, mosquito-borne viruses (MBVs) circulate between vertebrate animals and mosquitoes and represent a serious threat to humans via spillover from enzootic cycles to the human community. Active surveillance of MBVs in their vectors is therefore essential to better understand and prevent spillover and emergence, especially at the human–animal interface. In this study, we assessed the presence of MBVs using molecular and phylogenetic methods in mosquitoes collected along an ecological gradient ranging from rural urbanized areas to highland forest areas in northern Thailand. We have detected the presence of insect specific flaviviruses in our samples, and the presence of the emerging zoonotic Tembusu virus (TMUV). Reported for the first time in 1955 in Malaysia, TMUV remained for a long time in the shadow of other flaviviruses such as dengue virus or the Japanese encephalitis virus. In this study, we identified two new TMUV strains belonging to cluster 3, which seems to be endemic in rural areas of Thailand and highlighted the genetic specificities of this Thai cluster. Our results show the active circulation of this emerging flavivirus in Thailand and the need for continuous investigation on this poorly known but threatening virus in Asia. [ABSTRACT FROM AUTHOR]

Purpose of Review: West Nile virus (WNV) is an arbovirus transmitted by mosquitos of the genus Culex. Manifestations of WNV infection range from asymptomatic to devastating neuroinvasive disease leading to flaccid paralysis and death. This review examines WNV epidemiology and ecology, with an emphasis on travel-associated infection. Recent Findings: WNV is widespread, including North America and Europe, where its range has expanded in the past decade. Rising temperatures in temperate regions are predicted to lead to an increased abundance of Culex mosquitoes and an increase in their ability to transmit WNV. Although the epidemiologic patterns of WNV appear variable, its geographic distribution most certainly will continue to increase. Travelers are at risk for WNV infection and its complications. Literature review identified 39 cases of documented travel-related WNV disease, the majority of which resulted in adverse outcomes, such as neuroinvasive disease, prolonged recovery period, or death. Summary: The prediction of WNV risk is challenging due to the complex interactions of vector, pathogen, host, and environment. Travelers planning to visit endemic areas should be advised regarding WNV risk and mosquito bite prevention. Evaluation of ill travelers with compatible symptoms should consider the diagnosis of WNV for those visiting in endemic areas as well as for those returning from destinations with known WNV circulation. [ABSTRACT FROM AUTHOR]

More than 100 countries suffer from mosquito-borne diseases which are prevalent across the world. They are the known vectors for transmission of dengue, malaria, yellow fever, filariasis, Japanese encephalitis, schistosomiasis etc. Many of the insecticides that are currently used in mosquito control have harmful effects on human health and other non-target populations, they are non-biodegradable in nature, and also have a higher rate of biomagnification in our ecosystem. The spike in insecticide resistance on a global scale is raising serious concerns. Therefore, search for natural, eco-friendly alternatives such as bio-insecticides is imperative. In this study, Larvicidal activity of the essential oil obtained from the leaves of Callistemon citrinus was tested on the Dengue vector mosquito Aedes aegypti and Chikungunya vector mosquito Culex sp. Also, the chemical composition of the essential oil was studied using GC-MS analysis. Callistemon citrinus can now be considered one of such bio-insecticides which is easily available throughout India, with many therapeutic active constituents in its essential oil and 80-100% larvicidal activity. [ABSTRACT FROM AUTHOR]

The results of the present study show the biological effects of ethyl elcoholic and aquatic extracts as well as alkaloids compounds of Atriplex helmius and Capparis spinosa roots. The results demonstrated the superiority of the cold aqueous extract of C. capparis at the highest concentration of 20 mg / ml, as the killing rate was 81.16% for the second larval instar of Cx. pipiens after 72 hours of exposure. While, the killing rate caused by the same treatment was 79.52% for the third larval instar. The results also showed the superiority of the alcoholic extract against C. spinosa, as the killing rate reached 98.55% for the second larval instar after 72 hours of treatment at a concentration of 20 mg/ml. As for A. halmius extract, the same treatment caused the lowest killing rate of 89.27% for the third instar of Cx. pipiens. The study also showed significant effects of the raw alkaline compound' s extracts of A. halimus roots on the killing of non-adult instars of Cx. pipiens L. The highest rate of mortality observed was 88.54% at the highest concentration of 20 mg /ml at the second instar. Also, significant effects of raw alkaline compound's extracts of C. spinosa roots were observed. The highest mortality was 69.21% at the highest concentration of 20 mg/ml for the third larval instar, [ABSTRACT FROM AUTHOR]

Different species of Culex mosquitoes are present in high numbers in many other countries in addition to sub-Saharan Africa and Asian countries. Culex mosquitoes are serious nuisance which also transmit a range of pathogens including several viruses such as West Nile virus, Saint Louis encephalitis, and Rift Valley fever, as well as parasites such as avian malaria, and filarial worms. In Ethiopia, unlike Anopheles mosquitoes, little effort was given to study habitat, species composition, blood meal sources and insecticide susceptibility status of Culex mosquitoes. Therefore, this study aimed to assess the species composition, their blood meal source and insecticide susceptibility status of Culex mosquitoes to some of selected insecticides in Jimma town southwest Ethiopia. Culicine mosquito larvae were collected using a standard dipper (by dipping) from a range of breeding sites and reared to adults. Species identification was carried out using standard keys. Bioassay tests were performed on adults to assess the susceptibility of Culex mosquitoes to insecticide-impregnated papers with Dichlorodiphenyltrichloroethane (DDT (4%), mlathion (5%), bendiocarb (0.1%), propoxur (0.1%), deltamethrin (0.05%) and pirimiphos-methyl (0.25) following World Health Organization Pesticide Evaluation Scheme (WHOPES) guideline. Moreover, 184 blood fed (BF) Culex mosquitoes were collected using aspirator from indoor and outdoor resting and assayed to assess blood meal sources using Enzyme-Linked Immunosorbent Assay (ELISA). The result of the study showed that among the collected Culex moquitoes, two species were identified as Culex quinquefasciatus and Cx antennatus whereas the remaining one could not be identified to species level. Culex mosquitoes were found to be resistant to DDT, malathion, bendiocarb, propoxur, and deltamethrin whereas susceptible to pirimiphos-methyl. The blood meal source analysis using Enzyme-Linked Immunosorbent Assay (ELISA) showed higher blood source of human (33.2%) than bovine (15.2%). Thus, the observed resistance to the most of the insecticides coupled with higher human blood meal source calls further studies to be carried out in Culex mosquito populations of Ethiopia. [ABSTRACT FROM AUTHOR]

Abstract Background Many arboviral outbreaks have occurred in various locations in Kenya. Entomological surveys are suitable methods for revealing information about circulating arboviruses before human outbreaks are recognized. Therefore, mosquitoes were collected in Kenya to determine the distribution of arboviruses. Methods Various species of mosquitoes were sampled from January to July 2012 using several collection methods. Mosquito homogenates were directly tested by reverse transcription-polymerase chain reaction (RT-PCR) using various arbovirus-targeted primer pairs. Results We collected 12,569 mosquitoes. Although no human-related arboviruses were detected, Culex flavivirus (CxFV), an insect-specific arbovirus, was detected in 54 pools of 324 Culex quinquefasciatus individuals collected during the rainy season. Of these 54 positive pools, 96.3% (52/54) of the mosquitoes were collected in Busia, on the border of western Kenya and Uganda. The remaining two CxFV-positive pools were collected in Mombasa and Kakamega, far from Busia. Phylogenetic analysis revealed minimal genetic diversity among the CxFVs collected in Mombasa, Kakamega, and Busia, even though these cities are in geographically different regions. Additionally, CxFV was detected in one mosquito pool collected in Mombasa during the dry season. In addition to Culex mosquitoes, Aedes (Stegomyia) and Anopheles mosquitoes were also positive for the Flavivirus genus. Cell fusing agent virus was detected in one pool of Aedes aegypti. Mosquito flavivirus was detected in three pools of Anopheles gambiae s.l. collected in the dry and rainy seasons. Conclusions Although no mosquitoes were positive for human-related arbovirus, insect-specific viruses were detected in various species of mosquitoes. The heterogeneity observed in the number of CxFVs in Culex mosquitoes in different locations in Kenya suggests that the abundance of human-related viruses might differ depending on the abundance of insect-specific viruses. We may have underestimated the circulation of any human-related arbovirus in Kenya, and the collection of larger samples may allow for determination of the presence of human-related arboviruses.

The history of the scientific name of the yellow fever mosquito, the vector of yellow fever virus, ranges from 1757 to the early twenty-first century. In his 1757 work Iter Palæstinum, Frederic Hasselquist gave the name Culex aegypti to a mosquito species responsible for fierce attacks on humans in Egypt. That name was never later ascribed to Hasselquist as author, but to Linnaeus, although the name never appeared in any of Linnaeus' publications. In Cuba, at the end of the nineteenth century, the vector of the unknown infectious agent of yellow fever was first identified as Culex mosquito and later more validly named Stegomyia fasciata. Mosquito taxonomists differed strongly about the name of the mosquito through much of the twentieth century. Interventions by the International Commission on Zoological Nomenclature imposed a biologically invalid specific name, and in the early twenty-first century a phylogenetic analysis of the culicid tribe Aedini restored the genus Stegomyia from a century earlier. That action was short-lived. A phylogenetic reassessment resulted in the return of Stegomyia to subgeneric rank in Aedes; thus, the name of the yellow fever mosquito survives in the traditional classification of convenience as the trinomial Aedes (Stegomyia) aegypti (Linnaeus). [ABSTRACT FROM AUTHOR]

The Flavivirus genus is in the family Flaviviridae and is comprised of more than 70 viruses. These viruses have a broad geographic range, circulating on every continent except Antarctica. Mosquito-borne flaviviruses, such as yellow fever virus, dengue virus serotypes 1–4, Japanese encephalitis virus, and West Nile virus are responsible for significant human morbidity and mortality in affected regions. This review focuses on what is known about flavivirus-mosquito interactions and presents key data collected from the field and laboratory-based molecular and ultrastructural evaluations.

The Bunyaviridae family is comprised of more than 350 viruses, of which many within the Hantavirus, Orthobunyavirus, Nairovirus, Tospovirus, and Phlebovirus genera are significant human or agricultural pathogens. The viruses within the Orthobunyavirus, Nairovirus, and Phlebovirus genera are transmitted by hematophagous arthropods, such as mosquitoes, midges, flies, and ticks, and their associated arthropods not only serve as vectors but also as virus reservoirs in many cases. This review presents an overview of several important emerging or re-emerging bunyaviruses and describes what is known about bunyavirus-vector interactions based on epidemiological, ultrastructural, and genetic studies of members of this virus family.

Culex mosquitoes are vectors of Lymphatic filariasis and Japanese encephalitis diseases and the control of these diseases using synthetic chemical insecticides such as Pyrethroids results in development of resistance by the mosquitoes and polluting the ecosystem. This research was aim at evaluating the adulticidal potentials of dichloromethane extracts of some selected plant leaves against Culex mosquitoes. The results of the phytochemical screening analysis of the dichloromethane extracts shows that, Cymbopogon citratus, Mentha piperita and Ocimum citriodorum contained the highest number of phytochemicals four (4) each, followed by Lamium pupureum and Zingiber officinale having three (3) the last extracts having the least phytochemicals is Senna occidantalis which contains only two (2). The results of the adulticidal bioassay of the extracts shows that Cymbopogon citratus exhibited the highest adulticidal activities against the Culex mosquitoes tested at the LC5o5.721mg/mland LC9o 211.703mg/ml. The percentage mortality was recorded highest at the highest concentration 20mg/ml (87%), followed by lOmg/ml (74%) and 5mg/ml (43°/o). The mean average mortality and standard error were also recorded at 21.7±0.47, 18.5±3.01 and 10.7±1.37 respectively. From these results, it can be concluded that, the adulticidal activity of an extract depends on the solvent used in the extraction. Cymbopogon citratus extract was an excellent potentials for controlling Culex mosquitoes. Therefore we recommend that it should be used to control Culex mosquito in the affected areas. [ABSTRACT FROM AUTHOR]

Ciliate protists and rotifers are ubiquitous in aquatic habitats and can comprise a significant portion of the microbial food resources available to larval mosquitoes, often showing substantial declines in abundance in the presence of mosquito larvae. This top-down regulation of protists is reported to be strong for mosquitoes inhabiting small aquatic containers such as pitcher plants or tree holes, but the nature of these interactions with larval mosquitoes developing in other aquatic habitats is poorly understood. We examined the effects of these two microbial groups on lower trophic level microbial food resources, such as bacteria, small flagellates, and organic particles, in the water column, and on Culex larval development and adult production. In three independent laboratory experiments using two microeukaryote species (one ciliate protist and one rotifer) acquired from field larval mosquito habitats and cultured in the laboratory, we determined the effects of Culex nigripalpus larval grazing on water column microbial dynamics, while simultaneously monitoring larval growth and development. The results revealed previously unknown interactions that were different from the top-down regulation of microbial groups by mosquito larvae in other systems. Both ciliates and rotifers, singly or in combination, altered other microbial populations and inhibited mosquito growth. It is likely that these microeukaryotes, instead of serving as food resources, competed with early instar mosquito larvae for microbes such as small flagellates and bacteria in a density-dependent manner. These findings help our understanding of the basic larval biology of Culex mosquitoes, variation in mosquito production among various larval habitats, and may have implications for existing vector control strategies and for developing novel microbial-based control methods. [ABSTRACT FROM AUTHOR]

The Flavivirus genus is in the family Flaviviridae and is comprised of more than 70 viruses. These viruses have a broad geographic range, circulating on every continent except Antarctica. Mosquito-borne flaviviruses, such as yellow fever virus, dengue virus serotypes 1-4, Japanese encephalitis virus, and West Nile virus are responsible for significant human morbidity and mortality in affected regions. This review focuses on what is known about flavivirus-mosquito interactions and presents key data collected from the field and laboratory-based molecular and ultrastructural evaluations. [ABSTRACT FROM AUTHOR]

The Bunyaviridae family is comprised of more than 350 viruses, of which many within the Hantavirus, Orthobunyavirus, Nairovirus, Tospovirus, and Phlebovirus genera are significant human or agricultural pathogens. The viruses within the Orthobunyavirus, Nairovirus, and Phlebovirus genera are transmitted by hematophagous arthropods, such as mosquitoes, midges, flies, and ticks, and their associated arthropods not only serve as vectors but also as virus reservoirs in many cases. This review presents an overview of several important emerging or re-emerging bunyaviruses and describes what is known about bunyavirus-vector interactions based on epidemiological, ultrastructural, and genetic studies of members of this virus family. [ABSTRACT FROM AUTHOR]

The epidemiology of vector-borne pathogens is largely determined by the host-choice behaviour of their vectors. Here, we investigate whether a Plasmodium infection renders the host more attractive to host-seeking mosquitoes. For this purpose, we work on a novel experimental system: the avian malaria parasite Plasmodium relictum, and its natural vector, the mosquito Culex pipiens. We provide uninfected mosquitoes with a choice between an uninfected bird and a bird undergoing either an acute or a chronic Plasmodium infection. Mosquito choice is assessed by microsatellite typing of the ingested blood. We show that chronically infected birds attract significantly more vectors than either uninfected or acutely infected birds. Our results suggest that malaria parasites manipulate the behaviour of uninfected vectors to increase their transmission. We discuss the underlying mechanisms driving this behavioural manipulation, as well as the broader implications of these effects for the epidemiology of malaria. [ABSTRACT FROM AUTHOR]

Japanese encephalitis was recently reported from individuals in the mountain districts of Nepal without travel history to Japanese encephalitis virus (JEV) endemic areas. We performed a cross-sectional study to estimate the seroprevalence of JEV in pigs and subsequently conducted a survey of farmers to identify risk factors associated with seropositivity. In July and August, 2010, 454 pig serum samples were collected and tested by competitive ELISA. Data from a 35-question survey of 109 pig owners were analysed using multivariate logistic regression. Seventy-six (16.7, 95% CI 13.6-20.4) pigs tested positive for anti-JEV antibodies, none of which had been vaccinated against JEV or sourced from JEV endemic areas. Risk factors associated with JEV seropositivity were 'summer abortion', 'wells as a water source', 'urban location', 'reported presence of mosquitoes' and 'lower elevation'. Our results suggest that JEV is likely circulating in the mountain districts of Nepal, and that locally acquired JEV should be considered a risk for residents and travellers in these areas. [ABSTRACT FROM AUTHOR]

Avian malaria is a worldwide mosquito-borne disease caused by Plasmodium parasites. These parasites occur in many avian species but primarily affect passerine birds that have not evolved with the parasite. Host pathogenicity, fitness, and population impacts are poorly understood. In contrast to continental species, introduced avian malaria poses a substantial threat to naive birds on Hawaii, the Galapagos, and other archipelagoes. In Hawaii, transmission is maintained by susceptible native birds, competence and abundance of mosquitoes, and a disease reservoir of chronically infected native birds. Although vector habitat and avian communities determine the geographic distribution of disease, climate drives transmission patterns ranging from continuous high infection in warm lowland forests, seasonal infection in midelevation forests, and disease-free refugia in cool high-elevation forests. Global warming is expected to increase the occurrence, distribution, and intensity of avian malaria across this elevational gradient and threaten high-elevation refugia, which is the key to survival of many susceptible Hawaiian birds. Increased temperatures may have already increased global avian malaria prevalence and contributed to an emergence of disease in New Zealand. [ABSTRACT FROM AUTHOR]

We sought to estimate West Nile virus (WNV) activity in mosquito populations weekly at the census tract level in Chicago, IL, and to provide this information graphically. Each week we calculated a vector index (VI) for each mosquito trap then generated tract estimates using geographic information systems. During June 29-September 13, 2008, a median of 527 (60%) of 874 possible tracts per week had a VI value. Overall, 94% of the weekly VI tract estimates were 0; among those with a VI estimate greater than 0, the median was 0.33 (range 0.003-3.5). Officials deemed risk levels and weather conditions appropriate for adulticide treatments on 3 occasions, resulting in the treatment of approximately 252 linear kilometers of residential streets and alleys. Our analysis successfully converted complex, raw surveillance data into a format that highlighted areas of elevated WNV activity and facilitated the determination of appropriate response procedures. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To determine lead level primarily in Culex quinquefasciatus (Cx. quinquefasciatus), and Culex gelidus (Cx. gelidus) larvae inhabiting lead consuming factories, and to putatively estimate eco–toxicological impact of effluents from the firms. Methods: Third instars larvae were sampled by standard dipping method and lead concentrations in the larvae and their respective surrounding factory aquatic environments were determined through standard atomic absorption spectrophotometry (AAS). Results: Cx. quinquefasciatus was the most abundant species followed by Cx. gelidus. The levels of lead were higher in the Cx. quinquefasciatus (1.08–47.47 μg/g), than in the wastewaters surface (0.01–0.78 μg/mL) from the factories or closer areas around factories. Other species were not reaching the criteria for lead determination. Conclusions: The Cx. quinquefasciatus larvae can bio–accumulate the metal and can potentially serve as a biomarker of lead contamination, to complemente conventional techniques. [Copyright &y& Elsevier]

Abstract: Two infectious agents were isolated from Culex species mosquitoes in Japan and were identified as distinct strains of a new RNA virus by a method for sequence-independent amplification of viral nucleic acids. The virus designated Omono River virus (OMRV) replicated in mosquito cells in which it produced a severe cytopathic effect. Icosahedral virus particles of approximately 40nm in diameter were detected in the cytoplasm of infected cells. The OMRV genome was observed to consist of a nonsegmented, 7.6-kb double-stranded RNA (dsRNA) and contain two overlapping open reading frames (ORFs), namely ORF1 and ORF2. ORF1 was found to encode a putative dsRNA-binding protein, a major capsid protein, and other putative proteins, which might be generated by co- and/or post-translational processing of the ORF1 polyprotein precursor, and ORF2 was found to encode a putative RNA-dependent RNA polymerase (RdRp), which could be translated as a fusion with the ORF1 product by a −1 ribosomal frameshift. Phylogenetic analysis based on RdRp revealed that OMRV is closely related to penaeid shrimp infectious myonecrosis virus and Drosophila totivirus, which are tentatively assigned to the family Totiviridae. These results indicated that OMRV is a new member of the family of nonsegmented dsRNA viruses infecting arthropod hosts, but not fungal or protozoan hosts. [ABSTRACT FROM AUTHOR]