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Malaria in Bhutan has fallen significantly over the last decade. As Bhutan attempts to eliminate malaria in 2022, this study aimed to characterize the space–time clustering of malaria from 2010 to 2019. Malaria data were obtained from the Bhutan Vector-Borne Disease Control Program data repository. Spatial and space–time cluster analyses of Plasmodium falciparum and Plasmodium vivax cases were conducted at the sub-district level from 2010 to 2019 using Kulldorff’s space–time scan statistic. A total of 768 confirmed malaria cases, including 454 (59%) P. vivax cases, were reported in Bhutan during the study period. Significant temporal clusters of cases caused by both species were identified between April and September. The most likely spatial clusters were detected in the central part of Bhutan throughout the study period. The most likely space–time cluster was in Sarpang District and neighboring districts between January 2010 to June 2012 for cases of infection with both species. The most likely cluster for P. falciparum infection had a radius of 50.4 km and included 26 sub-districts with a relative risk (RR) of 32.7. The most likely cluster for P. vivax infection had a radius of 33.6 km with 11 sub-districts and RR of 27.7. Three secondary space–time clusters were detected in other parts of Bhutan. Spatial and space–time cluster analysis identified high-risk areas and periods for both P. vivax and P. falciparum malaria. Both malaria types showed significant spatial and spatiotemporal variations. Operational research to understand the drivers of residual transmission in hotspot sub-districts will help to overcome the final challenges of malaria elimination in Bhutan.

Contains fulltext : 232012.pdf (Publisher’s version ) (Open Access) Anopheles stephensi mosquitoes, efficient vectors in parts of Asia and Africa, were found in 75.3% of water sources surveyed and contributed to 80.9% of wild-caught Anopheles mosquitoes in Awash Sebat Kilo, Ethiopia. High susceptibility of these mosquitoes to Plasmodium falciparum and vivax infection presents a challenge for malaria control in the Horn of Africa.

Summary Latent forms of Plasmodium vivax, called hypnozoites, cause malaria relapses from the liver into the bloodstream and are a major obstacle to malaria eradication. To experimentally assess the impact of a partially protective pre-erythrocytic vaccine on reducing Plasmodium vivax relapses, we developed a liver-humanized mouse model that allows monitoring of relapses directly in the blood. We passively infused these mice with a suboptimal dose of an antibody that targets the circumsporozoite protein prior to challenge with P. vivax sporozoites. Although this regimen did not completely prevent primary infection, antibody-treated mice experienced 62% fewer relapses. The data constitute unprecedented direct experimental evidence that suboptimal efficacy of infection-blocking antibodies, while not completely preventing primary infection, has a pronounced benefit in reducing the number of relapses. These findings suggest that a partially efficacious pre-erythrocytic Plasmodium vivax vaccine can have a disproportionately high impact in positive public health outcomes.

Background Malaria remains an endemic disease in Pakistan with an estimated healthcare burden of 1.6 million cases annually, with Plasmodium vivax accounting for 67% of reported cases. P. vivax is the most common species causing malaria outside of Africa, with approximately 13.8 million reported cases worldwide. Method We report a series of P. vivax cases with cerebral involvement that presented at Aga Khan University Hospital, Karachi, Pakistan. Results The majority of the patients presented with high-grade fever accompanied by projectile vomiting and abnormal behaviour, seizures, shock and unconsciousness. Seven of 801 patients with P. vivax monoinfection presented or developed cerebral complications. P. vivax infections were diagnosed based on peripheral smears and rapid diagnostic testing. Conclusion P. vivax infection can lead to severe complications, although not with the frequency of Plasmodium falciparum infection. Current cases highlight an increasing trend of cerebral complications caused by P. vivax.

In South America, Plasmodium vivax resistance to chloroquine was recently reported in Brazil and Bolivia. The objective of this study was to collect data on chloroquine resistance in French Guiana by associating a retrospective evaluation of therapeutic efficacy with an analysis of recurrent parasitemia from any patients. Patients with P. vivax infection, confirmed by microscopy and a body temperature of ≥37.5°C, were retrospectively identified at Cayenne Hospital between 2009 and 2015., In South America, Plasmodium vivax resistance to chloroquine was recently reported in Brazil and Bolivia. The objective of this study was to collect data on chloroquine resistance in French Guiana by associating a retrospective evaluation of therapeutic efficacy with an analysis of recurrent parasitemia from any patients. Patients with P. vivax infection, confirmed by microscopy and a body temperature of ≥37.5°C, were retrospectively identified at Cayenne Hospital between 2009 and 2015. Follow-up and treatment responses were performed according to the World Health Organization protocol. Parasite resistance was confirmed after dosage of a plasma concentration of chloroquine and microsatellite characterization. The pvmdr1 and pvcrt-o genes were analyzed for sequence and gene copy number variation. Among the 172 patients followed for 28 days, 164 presented adequate clinical and parasitological responses. Eight cases of treatment failures were identified (4.7%; n = 8/172), all after 14 days. The therapeutic efficacy of chloroquine was estimated at 95.3% (95% confidence interval [CI], 92.5 to 98.1%; n = 164/172). Among the eight failures, five were characterized: two cases were true P. vivax chloroquine resistance (1.2%; 95% CI, 0 to 2.6%; n = 2/172), and three cases were found with subtherapeutic concentrations of chloroquine. No particular polymorphism in the Plasmodium vivax pvmdr1 and pvcrt-o genes was identified in the resistant parasites. This identified level of resistance of P. vivax to chloroquine in French Guiana does not require a change in therapeutic recommendations. However, primaquine should be administered more frequently to limit the spread of resistance, and there is still a need for a reliable molecular marker to facilitate the monitoring of P. vivax resistance to chloroquine.

Although Plasmodium vivax infections in Malaysia are usually imported, a significant autochthonous outbreak of vivax malaria was detected in a remote indigenous (Orang Asli) settlement located in northern peninsular Malaysia. Between November 2016 and April 2017, 164 cases of P. vivax infection were detected. Although 83.5% of the vivax cases were identified through passive case detection and contact screening during the first 7 weeks, subsequent mass blood screening (combination of rapid diagnostic tests, blood films, and polymerase chain reaction [PCR]) of the entire settlement (N = 3,757) revealed another 27 P. vivax infections, 19 of which were asymptomatic. The mapped data from this active case detection program was used to direct control efforts resulting in the successful control of the outbreak in this region. This report highlights the importance of proactive case surveillance and timely management of malaria control in Malaysia as it nears malaria elimination.

Plasmodium vivax is the main cause of malarial disease in Asia and South America. Plasmodium vivax infection was thought to be absent in African populations who are Duffy blood group antigen negative (Duffy-negative). However, many cases of P. vivax infection have recently been observed in Duffy-negative Africans. This raises the question: were P. vivax infections in Duffy-negative populations previously missed or has P. vivax adapted to infect Duffy-negative populations? This review focuses on recent P. vivax findings in Africa and reports views on the parasite ligands that may play a role in Duffy-negative P. vivax infections. In addition, clues gained from studying P. vivax infection of reticulocytes are presented, which may provide possible avenues for establishing P. vivax culture in vitro.

SummarySystems-scale analysis of multiple layers of molecular and cellular data has significant potential for providing novel insights into malaria pathology and immunity. We present here a unique longitudinal multi-omics dataset encompassingMacaca mulattablood and bone marrow responses to infection byPlasmodium cynomolgi, a non-human primate (NHP) parasite species used to modelP. vivaxmalaria acute and relapsing infections in humans. We analyzed relationships across multiple biological layers using a mutual information-based machine learning approach to integrate heterogeneous longitudinal datasets and constructed an atlas of multi-omics relatedness networks (MORNs). Using this technique, we were able to detect signatures that defined both acute and relapsing infections. Importantly, relapse infections could be distinguished from both acutely-infected and uninfected NHP, suggesting that the host-parasite interactions during relapses are unique compared to acutePlasmodiuminfections. To our knowledge, this is the first report of large-scale, longitudinal multi-omics analysis of malaria in any system. This dataset, along with the method used to analyze it, provides a unique resource for the malaria research community and demonstrates the power of longitudinal infection study designs, NHP model systems and integrative multi-omics analyses.

Background. Imported cases of Plasmodium vivax malaria from western Africa are reported annually in the Russian Federation. Infected native African people moving from western Africa for different purposes (students, businessmen, specialists, etc.) or Russian citizens (tourists, diplomats, businessmen, etc.) incubate the pathogen until reaching their Russian destination. Methods. All imported and other confirmed malaria cases and the associated Plasmodium species recorded over the past twenty years throughout the Russian Federation were inventoried. These data were included in the national register. The data of imported malaria cases were analysed according to the species of Plasmodium, case origin, dates of importation, and patient nationality. Results. A total of 267 P. vivax-infected patients who contracted the disease in western Africa were diagnosed in the Russian Federation from 1984 to 2017. Among them, 3 cases had mixed infections (2 with P. vivax + P. falciparum and 1 P. vivax + P. ovale). Conclusion. Our data reveal an existing risk of contracting P. vivax infections in towns of West sub-Saharan Africa despite the absence of local P. vivax infection records.

In Hyper endemic zones Malaria is known to present with unusual complications. Haemophagocytic syndrome is a disorder of mononuclear phagocytic syndrome. There are many published reports of haemophagocytic syndrome due to P. falciparum infection but haemophagocytic syndrome due to P. vivax infection is quite rare.J Nepal Paediatr Soc 2016;36(2):193-195.

Malaria remains a major public health problem in Brazil where Plasmodium vivax is the predominant species, responsible for 82% of registered cases in 2013. Though benign, P. vivax infection may sometimes evolve with complications and a fatal outcome. Here, we report a severe case of P. vivax malaria in a 35-year-old Brazilian man from a malaria endemic area, who presented with reversible myocarditis.

BACKGROUND Due to the recently observed rise in Plasmodium vivax incidence in Sudan and reported transmission in Duffy-negative individuals; we aimed to assess the possibility of P. vivax transmission in Duffy-negative individuals in Gezira state, central Sudan. METHOD A total of 126 suspected malaria patients were diagnosed with P. vivax infection using microscopy, RDT and PCR. PCR-RFLP was used to genotype participants Duffy status. RESULTS Forty eight (38%) were positive for P. vivax infection by PCR. Four patients (8.3%) were homozygous Duffy-negative. CONCLUSION These results confirm that P. vivax can infect Duffy-negative individuals, suggesting alternative mechanisms to bind and invade erythrocytes.

Background Although the malaria burden in the Lao PDR has gradually decreased, the elimination of malaria by 2030 presents many challenges. Microscopy and malaria rapid diagnostic tests (RDTs) are used to diagnose malaria in the Lao PDR; however, some studies have reported the prevalence of sub-microscopic Plasmodium infections or asymptomatic Plasmodium carriers in endemic areas. Thus, highly sensitive detection methods are needed to understand the precise malaria situation in these areas. Methodology/Principal findings A cross-sectional malaria field survey was conducted in 3 highly endemic malaria districts (Xaysetha, Sanamxay, Phouvong) in Attapeu province, Lao PDR in 2015, to investigate the precise malaria endemicity in the area; 719 volunteers from these villages participated in the survey. Microscopy, RDTs and a real-time nested PCR were used to detect Plasmodium infections and their results were compared. A questionnaire survey of all participants was also conducted to estimate risk factors of Plasmodium infection. Numbers of infections detected by the three methods were microscopy: P. falciparum (n = 1), P. vivax (n = 2); RDTs: P. falciparum (n = 2), P. vivax (n = 3); PCR: Plasmodium (n = 47; P. falciparum [n = 4], P. vivax [n = 41], mixed infection [n = 2]; 6.5%, 47/719). Using PCR as a reference, the sensitivity and specificity of microscopy were 33.3% and 100.0%, respectively, for detecting P. falciparum infection, and 7.0% and 100.0%, for detecting P. vivax infection. Among the 47 participants with parasitemia, only one had a fever (≥37.5°C) and 31 (66.0%) were adult males. Risk factors of Plasmodium infection were males and soldiers, whereas a risk factor of asymptomatic Plasmodium infection was a history of ≥3 malaria episodes. Conclusions/Significance There were many asymptomatic Plasmodium carriers in the study areas of Attapeu province in 2015. Adult males, probably soldiers, were at high risk for malaria infection. P. vivax, the dominant species, accounted for 87.2% of the Plasmodium infections among the participants. To achieve malaria elimination in the Lao PDR, highly sensitive diagnostic tests, including PCR-based diagnostic methods should be used, and plans targeting high-risk populations and elimination of P. vivax should be designed and implemented., Author summary The Lao People’s Democratic Republic (Laos) is a country in the Greater Mekong Subregion. In Laos, the numbers of reported cases of malaria and deaths due to malaria have been gradually decreasing. Recently, the Lao government adopted a goal of eliminating malaria by 2030. To achieve this goal, we must understand the precise situation in each endemic area. With this background, we conducted a field survey in Attapeu, one highly endemic province, in 2015. We collected blood samples from 719 villagers, and most (98.1%, 705/719) had no fever (

Malaria is one of the commonest parasitic diseases in the tropical countries like India. Complications of P. falciparum malaria are well recognised, but the complications of P. vivax malaria still continues to give us surprises. Myocardial involvement is a very rare complication of P. vivax infection. In this context, we report a case of P. vivax induced myocarditis and sinus exit block in our patient with review of the literature related to this rare entitiy.

BACKGROUND: After P. falciparum, P.vivax is the most significant malaria species, often both may coexist. Clinical features include fever, chills, sweating, headache, diarrhoea, abdominal pain, distension, cough, hepatomegaly and splenomegaly. Large studies from Islands of New guinea now show a strong association between P. vivax infection and severe disease and even death. MATERIAL AND METHODS: This was a cross sectional study, carried out in the department of Medicine, Surat Municipal Institute of Medical Education & Research during the period of June 2009 to August 2010. Patients of age 18 years or above fitting in the case definition of malaria with positive peripheral smear for P.vivax were included in the study. The details of the patients along with their clinical features, routine hematological and biochemical investigations were recorded in a standard proforma. The diagnosis of P.vivax was made from thick smear examination and if positive it was further confirmed by examining a thin smear slide. RESULTS: Most common clinical presentation was fever which was high grade, intermittent along with chills seen in 99% of patients. Bodyache, headache was observed in 65% & 61% respectively. Out of 140 patients 46(32%) had Hb >12gm% and 5(4%) had Hb

BACKGROUND: Malaria is commonly associated with various degrees of haematological complications most frequently with anaemia and thrombocytopenia. However there are contrasting reports about frequency of thrombocytopenia in P. vivax infection. MATERIAL AND METHODS: A total of 140 patients were included in the study. The details of the patients history along with their clinical features, laboratory reports were recorded in a standard proforma. Sample of venous blood were collected for haematological examination like Haemoglobin, total and differential count and platelet count, which was done under automated cell counter. RESULTS: Out of 140, there were 119(85%) patients who had thrombocytopenia, of them 75(54%) patients had mild, 38(27%) patients had moderate and 6(4%) patients had severe thrombocytopenia., 30(21%) out of 140 patients had leucopenia. Significant inverse association was seen between degree of parasitemia and platelet count. CONCLUSION: Various theories have been postulated for the cause of thrombocytopenia in P. Vivax infection but none of them is conclusive. Frequency or severity of thrombocytopenia doesn't appear to be any particular strain of plasmodium infection.

Dear Editor, Plasmodium vivax malaria accounts for 60-65% of total malaria cases in India. Vivax infections cause significant morbidity since in addition to the primary infection, dormant liver stages (hypnozoites) may re-emerge long after completion of full course of chloroquine treatment (25mg/kg) to cause relapses. The relapse patterns of P vivax are broadly divided into the tropical or Chesson strain type characterized by an early primary attack followed by a short latent period, the appearance of frequent relapses and the St. Elizabeth strain of the temperature type by an early primary attack and a long latent period of 6-14 months followed by relapses [1]. Primaquine is the drug used for radical cure of vivax malaria. The National Malaria Eradication Programme of India recommends primaquine in a dose of 15 mg/day for 5 days to all vivax malaria patients, which is also followed in the Armed Forces. WHO while advocating the treatment of malaria including prevention of relapses has categorized population based on their immune status with respect to malaria-immune, semi-immune and non-immune. While they advocate a 5 day primaquine regimen for the first two categories, they recommend a 14 day schedule for the non immune population. For some reasons, we in India have considered ourselves as either immune or semi-immune. Practically speaking, there can be no immune population. Further, immunity in malaria is so diverse on account of strain variation within the same species that a migratory or floating population like the Armed Forces can never be considered immune or semi-immune. It has an appropriate label as non-immune since we may be semi-immune to a strain at one place but moving on to another place may not be semi-immune or immune to the strain prevalent there. Most western authorities have also advocated a 14 day primaquine regimen [2]. However. for logistic and financial reasons. 5 day primaquine regimen has been preferred in India. Various relapse patterns have been reported from different parts of India. Adak et al reported in 1998. three relapse patterns from Northern India-tropical. temperate and intermediate [3]. A recently concluded study from Mumbai has reported a relapse pattern of predominantly tropical type. in which most of the relapses occurred in first 6 months of completion of chloroquine therapy [1]. A comparison of no primaquine. 5 day primaquine and 14 day primaquine has shown that the relapse rate is zero with 14 day regimen, 19.4% with the 5 day regimen and 11.4% with no primaquine regimen [4]. Another study has shown that rhe relapse rate with 5 day primaquine regimen is 13% [5], while it was 12.67% on no primaquine regimen as recently reported from Mumbai [1]. All patients who relapsed in this study showed complete response to the 14 day primaquine regimen. Another aspect that has often been deliberated is, whether the relapses that occur in vivax cases are true relapses or a fresh infection. Scientifically, only polymerase chain reaction test can determine this, which can be undertaken only in special circumstances or for research purpose and not as a routine. The protagon ists of ‘fresh vivax infection’ subscribe to the view on account of endemicity and transmission potential of malaria existing locally. This argument can well be countered in view of the above-mentioned studies wherein the rate of relapse (should we say suffering once again) was zero with 14 day primaquine regimen. Given the 13-19.4% relapse rate with 5 day primaquine regimen. the tropical type of relapse and complete response to the 14 day primaquine regimen. the utility of the 5 day regimen needs to be considered again. We have also seen cases of vivax malaria that have relapsed after 5 day primaquine regimen (personal communication. data not available). Based on the available data. we need to revise our existing national policy as well as that in the Armed Forces on radical cure of vivax malaria. Adopting the 14 day primaquine regimen will increase the duration of hospital admission from vivax malaria. but will ultimately decrease the expenditure incurred per patient of vivax malaria. We hope through this communication, to generate opinion from the experts in the field of malariology and also encourage debate on this issue at a larger forum.

Acre State Health Secretariat. Acre, AC, Brazil. Acre State Health Secretariat. Acre, AC, Brazil. Minist?rio da Sa?de. Secretaria de Vigil?ncia em Sa?de. Instituto Evandro Chagas. Ananindeua, PA, Brasil. Centers for Disease Control and Prevention. Center for Global Health. Division of Parasitic Diseases and Malaria. Malaria Branch. Atlanta, GA, USA / Atlanta Research and Education Foundation. Decatur, GA, USA. Centers for Disease Control and Prevention. Center for Global Health. Division of Parasitic Diseases and Malaria. Malaria Branch. Atlanta, GA, USA Acre State Health Secretariat. Acre, AC, Brazil. Brazilian Ministry of Health. National Malaria Control Program. Brasilia, DF, Brazil. Centers for Disease Control and Prevention. Center for Global Health. Division of Parasitic Diseases and Malaria. Malaria Branch. Atlanta, GA, USA Minist?rio da Sa?de. Secretaria de Vigil?ncia em Sa?de. Instituto Evandro Chagas. Ananindeua, PA, Brasil. Brazilian Ministry of Health. National Malaria Control Program. Brasilia, DF, Brazil. Centers for Disease Control and Prevention. Center for Global Health. Division of Parasitic Diseases and Malaria. Malaria Branch. Atlanta, GA, USA. We evaluated the efficacy of chloroquine and primaquine on uncomplicated Plasmodium vivax malaria in Cruzeiro do Sul, Brazil, in 2014. Patients ? 5 years of age with either fever or history of fever, and laboratoryconfirmed P. vivax monoinfection received chloroquine (total dose = 25 mg/kg) and primaquine (total dose = 3.5 mg/kg), and were followed up for 168 days (24 weeks). We used microsatellite genotyping to differentiate recurrent infections caused by heterologous parasites from those caused by homologous ones. No new P. vivax episode occurred by Day 28 among 119 enrolled patients, leading to Day 28, with adequate clinical and parasitological response (ACPR) of 100% (95% confidence interval [CI] = 96.7?100%). Twenty-eight P. vivax episodes occurred by Day 168, with uncorrected ACPR of 69.9% (95% CI = 59.5?79.0%). Fifteen of these episodes were caused by either homologous haplotypes or haplotypes that could not be determined. Excluding the 13 recurrent episodes caused by heterologous parasites, Day 168 microsatellite-corrected ACPR was estimated at 81.2% (95% CI = 71.0?89.1%). Chloroquine and primaquine remain efficacious to treat acute uncomplicated P. vivax infection, but moderate recurrence rates were observed within 24 weeks of follow-up.

Objectives. To evaluate the predictive value of thrombocytopenia in malaria. Patients and Methods. It was a prospective observational study on all febrile patients with thrombocytopenia presenting to the Medical Unit of Hayat Abad Medical Complex during November 2008 to November 2010. Results. Of the total of 228 patients with fever and thrombocytopenia, 121 patients (53%) proved to be suffering from malaria. Of them 82 patients (68%) had falciparum malaria while 39 patients (32%) had vivax infection. Of these 121 patients, platelet counts ranged between 25,000 and 150,000/dL with a mean value of 101,000/dL () and a median of 75,000/dL. Of the 107 patients who were not suffering from malaria, the counts ranged between 10,000 and 150,000/dL with a mean value of 58,000/dL () and median of 50,000/dL. Conclusions. The presence of thrombocytopenia may be a predictor of malaria in adult population.

To look for profile of severe malaria and contribution of vivax infection to malarial morbidity in North Indian children. Detailed clinical, biochemical and hematological characteristics of children hospitalized with severe malaria over last 3 y were recorded. Presence of malarial parasite on peripheral smear and/or positive antigen test was considered as diagnostic for malaria. A total of 131(55.3%) patients with Plasmodium vivax (Pv), 79 (33.3%) with Plasmodium falciparum (Pf) and 27 (11.4%) with mixed infections were admitted. Cerebral malaria, severe anemia and shock were significantly more frequently observed in Pf group, while hepatic, renal, respiratory, and bleeding complications were more commonly seen in Pv patients. Malaria mortality was highest in mixed infection (11.1%), followed by Pf (7.6%) and Pv (3%) group. Severe and fatal vivax malaria is an emerging recognized entity and challenges the perception of Pv as a benign disease. Further clinical studies and molecular research is required to understand emergence of severe malaria in vivax mono-infection.

In India, 1.2-1.5 million new cases of Plasmodium vivax occur each year. These cases are successfully treated with 600 mg chloroquine (adult dose). We report the results of malaria treatment of a 13-year-old girl from the Indian Oil Corporation (IOC), Mathura, India who contracted P. vivax infection. The infection failed to respond to 2 cycles of standard chloroquine therapy. The concentrations of chloroquine were monitored with high performance liquid chromatography (HPLC). The plasma and whole blood chloroquine concentrations were 260 and 106 micrograms/l respectively, while a 15 micrograms/l plasma concentration is considered lethal to P. vivax. Resistance in P. vivax to chloroquine was found at the IOC, Mathura.

Background A stenogamous colony of Anopheles cracens (A. dirus B) established 20 years ago in a Thai insectary proved susceptible to Plasmodium vivax. However, routine sporozoite production by feeding on field-collected blood samples has not been described. The setting-up of an A. cracens colony in an insectary on the Thai-Myanmar border and the process of using P. vivax field samples for the production of infectious sporozoites are described. Methods The colony was started in 2012 from egg batches that were sent from the Department of Parasitology, Faculty of Medicine, University of Chiang Mai, to the Shoklo Malaria Research Unit (SMRU), on wet filter paper in sealed Petri dishes. From May 2013 to December 2014, P. vivax-infected blood samples collected from patients seeking care at SMRU clinics were used for membrane feeding assays and sporozoite production. Results Mosquitoes were fed on blood samples from 55 patients, and for 38 (69 %) this led to the production sporozoites. The average number of sporozoites obtained per mosquito was 26,112 (range 328–79,310). Gametocytaemia was not correlated with mosquito infectiousness (p = 0.82), or with the number of the sporozoites produced (Spearman’s ρ = −0.016, p = 0.905). Infectiousness did not vary with the date of collection or the age of the patient. Mosquito survival was not correlated with sporozoite load (Spearman’s ρ = 0.179, p = 0.282). Conclusion Consistent and routine P. vivax sporozoites production confirms that A. cracens is highly susceptible to P. vivax infection. Laboratory-bred colonies of this vector are suitable for experimental transmission protocols and thus constitute a valuable resource. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0830-0) contains supplementary material, which is available to authorized users.

Background: Accurate information on the distribution of the tsetse fly is of paramount importance to better control animal trypanosomosis. Entomological and parasitological surveys were conducted in the tsetse belt of south-western Ethiopia to describe the prevalence of trypanosomosis (PoT), the abundance of tsetse flies (AT) and to evaluate the association with potential risk factors. Methods: The study was conducted between 2009 and 2012. The parasitological survey data were analysed by a random effects logistic regression model, whereas the entomological survey data were analysed by a Poisson regression model. The percentage of animals with trypanosomosis was regressed on the tsetse fly count using a random effects logistic regression model. Results: The following six risk factors were evaluated for PoT (i) altitude: significant and inverse correlation with trypanosomosis, (ii) annual variation of PoT: no significant difference between years, (iii) regional state: compared to Benishangul-Gumuz (18.0 %), the three remaining regional states showed significantly lower PoT, (iv) river system: the PoT differed significantly between the river systems, (iv) sex: male animals (11.0 %) were more affected than females (9.0 %), and finally (vi) age at sampling: no difference between the considered classes. Observed trypanosome species were T. congolense (76.0 %), T. vivax (18.1 %), T. b. brucei (3.6 %), and mixed T. congolense/vivax (2.4 %). The first four risk factors listed above were also evaluated for AT, and all have a significant effect on AT. In the multivariable model only altitude was retained with AT decreasing with increasing altitude. Four different Glossina species were identified i.e. G. tachinoides (52.0 %), G. pallidipes (26.0 %), G. morsitans submorsitans (15.0 %) and G. fuscipes fuscipes (7.0 %). Significant differences in catches/trap/day between districts were observed for each species. No association could be found between the tsetse fly counts and trypanosomosis prevalence. Conclusions: Trypanosomosis remains a constraint to livestock production in south-western Ethiopia. Four Glossina and three Trypanosoma species were observed. Altitude had a significant impact on AT and PoT. PoT is not associated with AT, which could be explained by the importance of mechanical transmission. This needs to be investigated further as it might jeopardize control strategies that target the tsetse fly population.

Andaman and Nicobar Islands, union territory of India were inhabited by 14 aboriginal tribes. Some of these tribal populations have already become extinct, and the numbers of the existing ones are also dwindling. This group of islands being highly endemic for malaria, it was considered worthwhile to study the hunter-gatherer primitive tribe, Jarawas, for their Duffy blood group phenotype. Jarawas, the primitive tribe of Andaman Islands, inhabit the three jungle areas of South and one jungle area of Middle Andaman. Blood samples of 116 Jarawas were collected and tested for Duffy blood group and malarial parasite infectivity. The Duffy blood grouping was performed as per standard serological techniques, and peripheral smears were screened for malarial parasite and if present parasite density count was performed and the species identified. The results showed a total absence of both Fy(a) and Fy(b) antigens in two areas (Kadamtala and R.K. Nallah) and low prevalence of Fy(a) antigen in another two areas (Jirkatang and Tirur). There was absence of malarial parasite Plasmodium vivax infection though Plasmodium falciparum infection was present in 27.59% of cases. A very high frequency of Fy (a-b-) in the Jarawa tribe from all the four jungle areas of Andaman Islands along with total absence of P. vivax infections suggests the selective advantage offered to Fy (a-b-) individuals against P vivax infection.

A study to assess the influence of re-invasion of Glossina pallidipes on the epidemiology of bovine trypanosomosis was conducted in Southeast Uganda. A total of 1,992 cattle were screened in villages, with (949) and without G. pallidipes (1043) for trypanosomosis using a combination of the BCT and HCT methods. The prevalence of trypanosomosis (15.5%), Trypanosoma brucei infection (1.4%), T. congolense infection (7.2%), T. vivax infection (5.3%) and mixed infection (1.6%) in cattle in villages with was significantly higher than in those without G. pallidipes: trypanosomosis (7.1%), T. brucei infection (0.6%), T. congolense infection (2.0%), T. vivax infection (3.3%) and mixed infection (1.2%) (overall trypanosome infection, chi2=35.5, d.f.=1, P0.05; T. brucei infection, chi2=8.06, d.f.=1, P0.05; T. congolense infection, chi2=22.8, d.f.=1, P0.05 and T. vivax infection, chi2=6.4, d.f.=1, P0.05). Infections of Trypanosoma congolense were predominant in cattle in villages with G. pallidipes, while T. vivax infections were predominant in cattle in villages without. In all villages, T. brucei infections were fewer than either T. congolense or T. vivax infections. The risk of transmission of T. brucei, T. congolense and T. vivax infections was 3, 2.7 and 1.6 times, respectively, higher in villages with G. pallidipes than in those without, despite the presence of G. f. fuscipes in either set of villages. The mean PCV (28.27+/-0.41, 95% CI) and mean herd size (3+/-0.46) of cattle in villages with G. pallidipes were significantly (P0.05) lower than in those in villages without (mean PCV, 29.48+/-0.34; mean herd size, 4+/-0.72). It is evident that presence of G. pallidipes brings about an increase in the prevalence of T. congolense, which causes a more severe disease in cattle than other species of trypanosomes. This is a rare case of a re-invasion of a tsetse species whose disease transmission capability calls for refocusing of the traditional national tsetse and trypanosomosis control strategies to contain it.

Acute hemorrhagic leukoencephalitis (AHLE, Hurst's disease) is a rare hyperacute variant of acute disseminated encephalomyelitis (ADEM) characterized by severe, rapidly progressive clinical illness and hemorrhagic necrosis of white matter. Like ADEM, it is often preceded by viral illness or vaccination. Plasmodium vivax infection is usually uncomplicated and non-fatal with only a handful of reports of central nervous system complications. In this article, we report a previously unknown association between AHLE and P. vivax infection.

The Aotus model for vivax malaria is extremely useful both as a source of living parasites in non-endemic areas, and as a model for vaccine and drug development research. Several species of New World primates can be infected with numerous different strains of Plasmodium vivax. This article reviews some aspects of the Aotus model, discusses the frequently observed hematological changes that can confound interpretation of hemogram data during the course of vivax infection, and provides a partial atlas of parasite forms and Aotus nancymai blood cells.

Since the turn of the century, a remarkable expansion has been achieved in the range and effectiveness of products and strategies available to prevent, treat, and control malaria, including advances in diagnostics, drugs, vaccines, and vector control. These advances have once again put malaria elimination on the agenda. However, it is clear that even with the means available today, malaria control and elimination pose a formidable challenge in many settings. Thus, currently available resources must be used more effectively, and new products and approaches likely to achieve these goals must be developed. This paper considers tools (both those available and others that may be required) to achieve and maintain malaria elimination. New diagnostics are needed to direct treatment and detect transmission potential; new drugs and vaccines to overcome existing resistance and protect against clinical and severe disease, as well as block transmission and prevent relapses; and new vector control measures to overcome insecticide resistance and more powerfully interrupt transmission. It is also essential that strategies for combining new and existing approaches are developed for different settings to maximise their longevity and effectiveness in areas with continuing transmission and receptivity. For areas where local elimination has been recently achieved, understanding which measures are needed to maintain elimination is necessary to prevent rebound and the reestablishment of transmission. This becomes increasingly important as more countries move towards elimination., David Kaslow and colleagues examine the progress in reasearch for diagnostics, drugs, vaccines, and vector control in malaria elimination and eradication and propose a research agenda.

SUMMARYMonitoring of malaria intensity in terrain regions of Arunachal Pradesh, India is very difficult as the dynamics of mosquito populations varies to a large extent due to altitude and frequent changes in climatic conditions. There is a scarcity of information on the influence of climatic factors on malaria morbidity in Arunachal Pradesh. Hence, a pilot study was conducted from 2006 to 2010 to understand malaria transmission dynamics, seasonal distribution and disease morbidity. Plasmodium vivax and P. falciparum are the two major parasites for malaria transmission in Arunachal Pradesh. Out of 142 558 malaria cases analysed from 2006 to 2010, P. vivax infection contributed 72·1% followed by P. falciparum (27·9%). However, the overall morbidity of malaria declined from 37/1000 in 2006 to 18/1000 population in 2010. From this study it was observed that the temporal distribution of malaria cases varied between districts and high morbidity rates were reported mostly during the wet season. To understand malaria transmission dynamics in the study area, the Richards model was used to predict malaria cases. The output of the results from this model predicted a higher number of malaria cases (K) during 2006 and a gradual decline in subsequent years. Similarly, the growth rate r, and exponential deviation α, were almost identical for all the years, which shows that the Richards model is the most suitable model for the prediction of malaria cases.

In September 1995, a Michigan resident with no history of international travel was diagnosed with Plasmodium vivax infection, and local mosquito-borne transmission was suspected. An epidemiological investigation did not identify additional cases of local transmission, and there was no apparent link to the 12 imported malaria cases detected in the region. Potential sites of nighttime outdoor exposure included a campground in a swampy area, close to a racetrack frequented by international travelers, some of whom were known to come from countries with malaria transmission. Entomological investigation identified Anopheles spp. larvae and adults near the campsite. Summer temperatures 4.2 degrees C above average would have contributed to shortened maturation time of P. vivax within the insect vector, increasing the likelihood of infectivity. These investigations indicated that this patient probably acquired P. vivax infection through the bite of a locally infected Anopheles spp. mosquito. Physicians need to consider malaria as a possible cause of unexplained febrile illness, even in the absence of international travel, particularly during the summer months.

A total of 73 cases of Plasmodium vivax infections acquired in Western or Central Africa were diagnosed on microscopical criteria in French travellers from 1995 to 1998. We report a case of P. vivax infection in a non immune traveller confirmed by polymerase chain reaction and presenting an atypical P. ovale morphology. The infection was acquired in Western or Central Africa. These microscopical observations, together with the molecular evidence for P. vivax in Western and Central Africa suggest that P. vivax is transmitted in this area despite lacking the Duffy receptor in autochthonous population.

Summary In field studies, tsetse flies (Diptera: Glossinidae) feed more successfully on cattle infected with Trypanosoma congolense Broden (Kinetoplastida: Trypanosomatidae) than on cattle infected with T. vivax Ziemann or uninfected cattle. Here we describe the first laboratory investigation of this phenomenon. In the first experiment, caged Glossina pallidipes Austen were fed for 1 and 5 min on a Boran steer infected with T. congolense clone IL 1180 and on an uninfected steer. Feeding success was recorded in this way five times over several weeks. The same protocol was subsequently used in three additional experiments with the following combinations: G. pallidipes and a steer infected with T. vivax stock IL 3913, G. morsitans centralis Machado and a steer infected with T. congolense, and G. morsitans centralis and a steer infected with T. vivax. The four experiments were replicated once, making eight experiments in total. In three experiments there was increased tsetse feeding success, measured at 1 min, after a steer became infected (T. congolense, two experiments and T. vivax, one experiment). Analysis of all data combined found no significant differences in tsetse feeding success on the different groups of cattle prior to infection, but after infection tsetse feeding success was significantly greater on the infected cattle (P

A survey was conducted in Song Local Government Area of Adamawa State on Trypanosomiasis to determine the influence of age, sex and breed on the susceptibility to the infection. A total of 240 blood samples of different breeds, Sexes and ages of cattle were collected from randomly selected herd and analyzed in laboratory using wet, thick, thin smear and Buffy coat concentration techniques. An overall infection rate in males and females were 9.17% and 17.50% respectively, infection rates in Red Bororo, Adamawa Gudali and White Fulani were found to be 13.16%, 14.00% and 12.00% respectively. The result shows that Adamawa gudali has the highiest with White Fulani cattle having the lowest rate of infectioon. Trjpanosoma vivax infection was 9.17% and Tiypanosoma congolence was 4.16%. This result shows that the trypanosomiasis in the area is of great economic importance.Key words: Trypanosomiasis, age, sex, breed.

Background There is large body of evidence that states that invasion of Plasmodium vivax requires the Duffy antigen, but the universality of this specificity is certainly now under question with recent reports showing that in some parts of the world P. vivax infects and causes disease in Duffy-negative people. These findings reinforce the idea that this parasite is rapidly evolving, being able to use other receptors than Duffy to invade the erythrocytes, which may have an enormous impact in P. vivax current distribution. The presence of P. vivax infection in Duffy-negative individuals was investigated in a cross-sectional study conducted in Anajás, Archipelago of Marajó, State of Pará, which is an area of malaria transmission in the Brazilian Amazonia. Methods Duffy genotyping and Plasmodium species diagnostic assays were performed successfully in 678 individuals. An allele-specific primer polymerase chain reaction (PCR) technique was used for Duffy blood group genotyping. Identification of Plasmodium species was achieved by conventional blood smear light microscopy and a TaqMan-based real-time PCR method to detect mitochondrial genome of Plasmodium falciparum and P. vivax. Results Plasmodium spp. infection was detected in 137 samples (20.2%). Prevalence of each Plasmodium species was 13.9% P. vivax, 5.8% P. falciparum, and 0.6% P. vivax plus P. falciparum. Overall, 4.3% (29/678) were genotyped as Duffy-negative (FY*B ES /*B ES ). Among Duffy-negative individuals 6.9% were P. vivax PCR positive and among Duffy-positive 14.2% were P. vivax PCR positive. Although lower, the risk of Duffy-negatives to experience a P. vivax blood stage infection was not significantly different to that of Duffy-positives. Furthermore, the genotypic and allelic frequencies of the Duffy blood group among P. vivax-infected patients and in the control group did not differ significantly, also suggesting no reduction in infection rates among the carriers of FY*B ES allele. Conclusions The data obtained in Anajás showed no differential resistance vivax malaria among Duffy-negative and Duffy-positive individuals. This result needs additional confirmation through a deeper evaluation in a larger sample of patients with P. vivax malaria and molecular parasite characterization. Nonetheless, this genetic profile of the parasite may be contributing to the high incidence of malaria in the municipality.

Background The Philippines is among the 39 countries aiming for malaria elimination. The major challenge is finding residual transmission foci in difficult to access villages of Southern Mindanao, Philippines. The sensitivity of microscopy to detect asymptomatic infections declines with decreasing malaria prevalence. The aim of this project is to use antibody markers of P. falciparum and P. vivax infection to locate residual transmission foci and to determine effects of control measures in Sarangani Province, the Philippines.

A cross-sectional survey of bovine trypanosomosis was carried out in Wemberma district of west Gojjam zone, North West Ethiopia. From three peasant associations in the district (one from the midland and two from lowland), 384 cattle were randomly selected and examined for trypanosomosis. The prevalence of the disease as determined by buffy coat techinque was 7.81(95% CI = 5.11- 10.5%). Trypanosoma vivax and T. congolense were detected from buffy coat positive samples. Among the total of 30 cases of trypanosome infections detected 24(80%) of the infections were due to T.vivax and the rest 6(20 %) were due to T. congolense . No statistically significant associations(P>0.05) were observed between the disease and potential risk factors like age, sex and agroecology. However, when the different species of trypanosomes were considered, T. congolense infections were found only in the lowland. A significant association was observed (P

For over 4 decades the antimalarial program in India has been prescribing a 5-day primaquine regimen as an antirelapse therapy to treat Plasmodium vivax malaria. In view of conflicting reports on the effectiveness of this regimen in the Indian subcontinent, and the varying prevalence of P. vivax in various ecosystems in India, the antirelapse efficacy of this regimen was evaluated in Orissa, a malaria endemic state in eastern India where P. falciparum predominates. In 723 cases of P. vivax infection treated with chloroquine alone and followed up weekly for 1 yr, the prevalence of recurrence of parasitaemia with fever was 8.6%. Among another 759 P. vivax cases treated with chloroquine and a 5-day regimen of primaquine at 15 mg/day (adult dose), the recurrence of infection was 6.5%. The difference in recurrence was not significant (P = 0.53). It is important to note that in a great majority of cases of P. vivax in this area, infection did not recur even without treatment with primaquine. This finding, that the use of the 5-day primaquine regimen with chloroquine had no significant advantage over the use of chloroquine alone, undermines the rationale of using primaquine as an antirelapse drug in forested areas with a high prevalence of P. falciparum.

Twelve Yankasa rams from 2.5 to 3 years of age were divided into two groups of six for a study which lasted 15 weeks. All the rams initially had low sperm morphological abnormalities in their semen before the six animals in the treatment group were infected with Trypanosoma vivax. All of the infected rams developed chronic trypanosomiasis. Detailed studies of sperm morphological abnormalities were carried out for a period of 9 weeks post infection (p.i.). There was a rapid and progressive elevation of all abnormalities in the semen of the infected rams. Typical spermatozoa of infected rams were highly deformed with multiple morphological abnormalities. At 9 weeks p.i. the control group of rams had a mean of 3.9% for total sperm morphological abnormalities which differed (P

Summary Phenanthridinium 1553 in a dosage of 2 mg./kg. by intravenous injection protected cattle against both T. vivax and T. congolense infection for periods up to one month after administration. Pigs were similarly protected after the subcutaneous injection of the drug in the same dosage against artificial T. vivax infection but no protection against T. congolense occurred. The drug had no protective or curative action against T. brucei infection in cattle, pigs, donkeys or dogs.

© 2010 licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited., For more than a decade, flow cytometry-based automated haematology analysers have been studied for malaria diagnosis. Although current haematology analysers are not specifically designed to detect malaria-related abnormalities, most studies have found sensitivities that comply with WHO malaria-diagnostic guidelines, i.e. ≥ 95% in samples with > 100 parasites/μl. Establishing a correct and early malaria diagnosis is a prerequisite for an adequate treatment and to minimizing adverse outcomes. Expert light microscopy remains the 'gold standard' for malaria diagnosis in most clinical settings. However, it requires an explicit request from clinicians and has variable accuracy. Malaria diagnosis with flow cytometry-based haematology analysers could become an important adjuvant diagnostic tool in the routine laboratory work-up of febrile patients in or returning from malaria-endemic regions. Haematology analysers so far studied for malaria diagnosis are the Cell-Dyn®, Coulter® GEN•S and LH 750, and the Sysmex XE-2100® analysers. For Cell-Dyn analysers, abnormal depolarization events mainly in the lobularity/granularity and other scatter-plots, and various reticulocyte abnormalities have shown overall sensitivities and specificities of 49% to 97% and 61% to 100%, respectively. For the Coulter analysers, a 'malaria factor' using the monocyte and lymphocyte size standard deviations obtained by impedance detection has shown overall sensitivities and specificities of 82% to 98% and 72% to 94%, respectively. For the XE-2100, abnormal patterns in the DIFF, WBC/BASO, and RET-EXT scatter-plots, and pseudoeosinophilia and other abnormal haematological variables have been described, and multivariate diagnostic models have been designed with overall sensitivities and specificities of 86% to 97% and 81% to 98%, respectively. The accuracy for malaria diagnosis may vary according to species, parasite load, immunity and clinical context where the method is applied. Future developments in new haematology analysers such as considerably simplified, robust and inexpensive devices for malaria detection fitted with an automatically generated alert could improve the detection capacity of these instruments and potentially expand their clinical utility in malaria diagnosis.

Plasmodium vivax infection causing severe malaria is increasingly being reported. Six children aged 1.5–11 years with severe vivax malaria who presented with cerebral malaria (three) and severe anaemia (two) are reported; two had altered renal function. Thrombocytopenia was detected in all cases. P. vivax infection should be considered in children presenting with severe malaria.

The prevalence of trypanosome infection in trade cattle, goats and sheep was investigated in slaughtered animals at the Kaduna Abattoir. Wet, thin, thick films, animal inoculation, haematocrit centrifugation technique and buffy coat methods were used to detect rypanosomes in the jugular blood of the animals. The packed cell volume (PCV) was also determined. A total of 300 cattle, 300 goats and 300 sheep were examined within five months (September, 1998 – January, 1999) and the prevalence rates in cattle, goats and sheep were found to be 5.00%, 4.67% and 3.33% respectively. Mean PCV of infected cattle was 20.33% against uninfected cattle 35.08%. In goats, the PCV was 20.29%, uninfected goats 31.56%; while that of sheep was 19.40% and uninfected 32.85%. Trypanosoma vivax infection accounted for 60%, T. brucei 26.67% and T. congolense 13.33% in cattle. In goats, T. vivax infection accounted for 71.43%, T. brucei 21.43% and T. congolense 7.14%. Also T. vivax infection accounted for 70%, T. brucei 30% and T. congolense 0% in sheep. Sex did not significantly (P>0.05) affect infection rates. Although the prevalence rate of trypanosomiasis in cattle, goats and sheep appeared low compared with the previous works, natural trypanosomiasis remains economically importance in cattle, goats and sheep in Nigeria. African Journal of Clinical and Experimental Microbiology Vol. 10 (1) 2009: pp. 15-25

The present study was conducted to study the susceptibility of two different types of Sudanese goats namely: Black Nubian, the Nilotic dwarf goats and ewes of Garag type to experimental infection with Trypanosoma vivax stock isolated from cattle outside tsetse area. The infection caused parasitaemia, anaemia and pyrexia in the infected goats. However, the Nilotic dwarf goats were more tolerant to the infection than the Nubian goats, showing significantly higher values of packed cell volume, haemoglobin concentration, total red and white blood cells counts and significantly low parasitaemia and low body temperature. Garag ewes which were found to be susceptible to T. vivax infection showed different signs of anaemia and pyrexia; it is recommended that comparative studies on sensitivity of this type and other different Sudanese types of sheep to Trypanosomosis should be conducted.