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Cameron MM, Acosta-Serrano A, Bern C, Boelaert M, den Boer M, Burza S, Chapman LAC, Chaskopoulou A, Coleman M, Courtenay O, Croft S, Das P, Dilger E, Foster G, Garlapati R, Haines L, Harris A, Hemingway J, Hollingsworth TD, Jervis S, Medley G, Miles M, Paine M, Picado A, Poché R, Ready P, Rogers M, Rowland M, Sundar S, de Vlas SJ, Weetman D. Understanding the transmission dynamics of Leishmania donovani to provide robust evidence for interventions to eliminate visceral leishmaniasis in Bihar, India. Parasit Vectors 2016; 9:25. [PMID: 26812963 PMCID: PMC4729074 DOI: 10.1186/s13071-016-1309-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 01/15/2016] [Indexed: 12/31/2022] Open
Abstract
Visceral Leishmaniasis (VL) is a neglected vector-borne disease. In India, it is transmitted to humans by Leishmania donovani-infected Phlebotomus argentipes sand flies. In 2005, VL was targeted for elimination by the governments of India, Nepal and Bangladesh by 2015. The elimination strategy consists of rapid case detection, treatment of VL cases and vector control using indoor residual spraying (IRS). However, to achieve sustained elimination of VL, an appropriate post elimination surveillance programme should be designed, and crucial knowledge gaps in vector bionomics, human infection and transmission need to be addressed. This review examines the outstanding knowledge gaps, specifically in the context of Bihar State, India.The knowledge gaps in vector bionomics that will be of immediate benefit to current control operations include better estimates of human biting rates and natural infection rates of P. argentipes, with L. donovani, and how these vary spatially, temporally and in response to IRS. The relative importance of indoor and outdoor transmission, and how P. argentipes disperse, are also unknown. With respect to human transmission it is important to use a range of diagnostic tools to distinguish individuals in endemic communities into those who: 1) are to going to progress to clinical VL, 2) are immune/refractory to infection and 3) have had past exposure to sand flies.It is crucial to keep in mind that close to elimination, and post-elimination, VL cases will become infrequent, so it is vital to define what the surveillance programme should target and how it should be designed to prevent resurgence. Therefore, a better understanding of the transmission dynamics of VL, in particular of how rates of infection in humans and sand flies vary as functions of each other, is required to guide VL elimination efforts and ensure sustained elimination in the Indian subcontinent. By collecting contemporary entomological and human data in the same geographical locations, more precise epidemiological models can be produced. The suite of data collected can also be used to inform the national programme if supplementary vector control tools, in addition to IRS, are required to address the issues of people sleeping outside.
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Picado A, Ostyn B, Rijal S, Sundar S, Singh SP, Chappuis F, Das ML, Khanal B, Gidwani K, Hasker E, Dujardin JC, Vanlerberghe V, Menten J, Coosemans M, Boelaert M. Long-lasting insecticidal nets to prevent visceral leishmaniasis in the Indian subcontinent; methodological lessons learned from a cluster randomised controlled trial. PLoS Negl Trop Dis 2015; 9:e0003597. [PMID: 25856238 PMCID: PMC4391877 DOI: 10.1371/journal.pntd.0003597] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
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Perry MR, Prajapati VK, Menten J, Raab A, Feldmann J, Chakraborti D, Sundar S, Fairlamb AH, Boelaert M, Picado A. Arsenic exposure and outcomes of antimonial treatment in visceral leishmaniasis patients in Bihar, India: a retrospective cohort study. PLoS Negl Trop Dis 2015; 9:e0003518. [PMID: 25730310 PMCID: PMC4346263 DOI: 10.1371/journal.pntd.0003518] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 01/05/2015] [Indexed: 11/22/2022] Open
Abstract
Background In the late twentieth century, emergence of high rates of treatment failure with antimonial compounds (SSG) for visceral leishmaniasis (VL) caused a public health crisis in Bihar, India. We hypothesize that exposure to arsenic through drinking contaminated groundwater may be associated with SSG treatment failure due to the development of antimony-resistant parasites. Methods A retrospective cohort design was employed, as antimony treatment is no longer in routine use. The study was performed on patients treated with SSG between 2006 and 2010. Outcomes of treatment were assessed through a field questionnaire and treatment failure used as a proxy for parasite resistance. Arsenic exposure was quantified through analysis of 5 water samples from within and surrounding the patient’s home. A logistic regression model was used to evaluate the association between arsenic exposure and treatment failure. In a secondary analysis survival curves and Cox regression models were applied to assess the risk of mortality in VL patients exposed to arsenic. Results One hundred and ten VL patients treated with SSG were analysed. The failure rate with SSG was 59%. Patients with high mean local arsenic level had a non-statistically significant higher risk of treatment failure (OR = 1.78, 95% CI: 0.7–4.6, p = 0.23) than patients using wells with arsenic concentration <10 μg/L. Twenty one patients died in our cohort, 16 directly as a result of VL. Arsenic levels ≥ 10 μg/L increased the risk of all-cause (HR 3.27; 95% CI: 1.4–8.1) and VL related (HR 2.65; 95% CI: 0.96–7.65) deaths. This was time dependent: 3 months post VL symptom development, elevated risks of all-cause mortality (HR 8.56; 95% CI: 2.5–29.1) and of VL related mortality (HR 9.27; 95% CI: 1.8–49.0) were detected. Discussion/Conclusion This study indicates a trend towards increased treatment failure in arsenic exposed patients. The limitations of the retrospective study design may have masked a strong association between arsenic exposure and selection for antimonial resistance in the field. The unanticipated strong correlation between arsenic exposure and VL mortality warrants further investigation. The parasitic disease visceral leishmaniasis (VL) causes a significant burden of illness and death in India. The main drug used to treat VL, which is based on the chemical element antimony, stopped working well in about half of all patients in the late twentieth century. We hypothesised that arsenic exposure of the Indian population, through contaminated groundwater, was contributing to treatment failure with antimony based drugs. Arsenic and antimony are similar chemical elements and exposure of the parasite to arsenic within the liver of arsenic-exposed patients could allow the parasite to become resistant to treatment with antimony. Using a field-based questionnaire study we retrospectively evaluated whether arsenic exposure was linked to antimonial treatment failure in a cohort of 110 antimonial treated patients. No significant association was found, although this may be because the number of patients in the study was low as antimony use was officially discontinued in 2005 due to high rates of treatment failure. However, arsenic exposure was found to increase risk of mortality from VL particularly if death occurred more than 3 months after the symptoms of VL developed. More research into the relationship between arsenic exposure and mortality in VL is warranted.
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Bates PA, Depaquit J, Galati EAB, Kamhawi S, Maroli M, McDowell MA, Picado A, Ready PD, Salomón OD, Shaw JJ, Traub-Csekö YM, Warburg A. Recent advances in phlebotomine sand fly research related to leishmaniasis control. Parasit Vectors 2015; 8:131. [PMID: 25885217 PMCID: PMC4352286 DOI: 10.1186/s13071-015-0712-x] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 02/03/2015] [Indexed: 11/30/2022] Open
Abstract
Phlebotomine sand flies are the subject of much research because of the role of their females as the only proven natural vectors of Leishmania species, the parasitic protozoans that are the causative agents of the neglected tropical disease leishmaniasis. Activity in this field was highlighted by the eighth International Symposium on Phlebotomine Sand flies (ISOPS) held in September 2014, which prompted this review focusing on vector control. Topics reviewed include: Taxonomy and phylogenetics, Vector competence, Genetics, genomics and transcriptomics, Eco-epidemiology, and Vector control. Research on sand flies as leishmaniasis vectors has revealed a diverse array of zoonotic and anthroponotic transmission cycles, mostly in subtropical and tropical regions of Africa, Asia and Latin America, but also in Mediterranean Europe. The challenge is to progress beyond descriptive eco-epidemiology, in order to separate vectors of biomedical importance from the sand fly species that are competent vectors but lack the vectorial capacity to cause much human disease. Transmission modelling is required to identify the vectors that are a public health priority, the ones that must be controlled as part of the integrated control of leishmaniasis. Effective modelling of transmission will require the use of entomological indices more precise than those usually reported in the leishmaniasis literature.
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Perry M, Wyllie S, Prajapati V, Menten J, Raab A, Feldmann J, Chakraborti D, Sundar S, Boelaert M, Picado A, Fairlamb A. Arsenic, antimony, and Leishmania: has arsenic contamination of drinking water in India led to treatment- resistant kala-azar? Lancet 2015; 385 Suppl 1:S80. [PMID: 26312902 DOI: 10.1016/s0140-6736(15)60395-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND In Bihar state, India, the cure rate of antimonial compounds (eg, sodium stibogluconate) in the treatment of visceral leishmaniasis (VL) has fallen from more than 85% to less than 50%. This reduction has been attributed to long-term, widespread misuse of antimonial drugs within the Indian private health-care system. We aimed to test the hypothesis that exposure to arsenic in drinking water in this region has resulted in antimony-resistant Leishmania parasites. METHODS L donovani parasites were serially passaged in mice exposed to environmentally relevant concentrations of arsenic in drinking water. Arsenic concentrations in murine organs were quantified and the sensitivity of L donovani to sodium stibogluconate assessed at each passage. A retrospective field study on a cohort of antimony-treated patients with VL was performed in an arsenic-contaminated area of Bihar to assess risk of treatment failure and death in people exposed to arsenic. FINDINGS Arsenic accumulation in organs of exposed mice was proportional to exposure level. After five passages, isolated parasites were refractory to sodium stibogluconate in in-vitro drug sensitivity assays. Treatment of arsenic exposed, infected mice with this drug confirmed that these parasites retained resistance in vivo. In the field work study, 110 patients with VL treated with sodium stibogluconate, failure rate was 59%. Patients using well water with high mean arsenic concentrations had a higher risk of treatment failure than patients using wells with arsenic levels of less than 10 μg/L (odds ratio 1·78, 95% CI 0·7-4·6, p=0·23). 21 patients died, 16 directly as a result of their disease. Mean arsenic concentrations of more than 10 μg/L increased the risk of all-cause and VL-related mortality (hazard ratio 3·27, 95% CI 1·4-8·1, and 2·65, 0·96-7·65, respectively). INTERPRETATION These data suggest that arsenic contamination might have contributed to the development of antimonial resistance in Leishmania parasites in Bihar. Our epidemiological study was underpowered and retrospective in nature, so firm conclusions cannot be made. Further research into the associations between arsenic exposure and antimonial treatment failure and death in the leishmaniases is warranted. FUNDING Wellcome Trust.
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Das ML, Rowland M, Austin JW, De Lazzari E, Picado A. Do Size and Insecticide Treatment Matter? Evaluation of Different Nets against Phlebotomus argentipes, the Vector of Visceral Leishmaniasis in Nepal. PLoS One 2014; 9:e114915. [PMID: 25494099 PMCID: PMC4262434 DOI: 10.1371/journal.pone.0114915] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 11/15/2014] [Indexed: 11/25/2022] Open
Abstract
In the Indian subcontinent, Leishmania donovani, the parasite causing visceral leishmaniasis (VL) is transmitted by the sand fly vector Phlebotomus argentipes. Long lasting insecticide treated nets (LN) have been postulated as alternative or complement to Indoor Residual Spraying but there are few field studies evaluating the entomological efficacy of different nets against this vector. We conducted two crossover trials in a VL endemic area in Nepal to compare the barrier effect of (1) LN with different mesh sizes (156 holes/inch2 vs 625 holes/inch2) and (2) alpha-cypermethrin treated LN and untreated nets having the same mesh size (156 holes/inch2). Each crossover trial had two arms consisting of a sequence of two different nets for 8 nights. We used 10 cattle sheds per trial. A cow placed under the net was used as bait. CDC light traps placed inside the nets were used to evaluate the number of P. argentipes crossing the net barrier. Negative binomial generalized estimating equation (GEE) population-averaged models adjusted by night and sequence were used to estimate the barrier effect of the different nets. The crossover trials conducted in a rural village in Morang district (South-eastern Nepal) demonstrated that reducing the size of the holes in treated nets (625 holes/inch2) increased the barrier effect of LN by 77% (95% confidence interval (CI): 56%-88%) compared with treated nets with larger holes (156 holes/inch2). Treating nets with alpha-cypermethrin reduced the number of P. argentipes captured inside the nets by 77% (95% CI: 27%-93%) compared with untreated nets. The effectiveness and acceptability of finer mesh pyrethroid treated LN should be tested for VL prevention in a randomized controlled trial.
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Lizundia R, Picado A, Cordero M, Calderón A, Deborggraeve S, Montenegro VM, Urbina A. Molecular and serological rapid tests as markers of Trypanosoma cruzi infection in dogs in Costa Rica. Trop Parasitol 2014; 4:111-4. [PMID: 25250232 PMCID: PMC4166795 DOI: 10.4103/2229-5070.138539] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 08/12/2014] [Indexed: 11/04/2022] Open
Abstract
Introduction: Chagas disease is a zoonotic disease caused by Trypanosoma cruzi and dogs are one of the main domestic reservoirs. Materials and Methods: One molecular (OligoC-TesT, Coris Bioconcept) and one serological (T. cruzi-Detect, Inbios) rapid tests were evaluated as infection markers for T. cruzi in 102 dogs living in eight villages endemic for Chagas in Costa Rica. Results: T. cruzi-Detect performed well as screening tool with 23.3% positive samples. The large number of invalid results (66.7%) observed in samples tested with OligoC-TesT precluded assessing the use of this new method as epidemiological tool to detect T. cruzi infection in dogs.
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Malaviya P, Picado A, Hasker E, Ostyn B, Kansal S, Singh RP, Shankar R, Boelaert M, Sundar S. Health & Demographic Surveillance System profile: the Muzaffarpur-TMRC Health and Demographic Surveillance System. Int J Epidemiol 2014; 43:1450-7. [PMID: 25186307 DOI: 10.1093/ije/dyu178] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The Muzaffarpur-TMRC Health and Demographic Surveillance System (HDSS), established in 2007, was developed as an enlargement of the scope of a research collaboration on the project Visceral Leishmaniasis in Bihar, which had been ongoing since 2005. The HDSS is located in a visceral leishmaniasis (VL)-endemic area in the Muzaffarpur district of Bihar state in India. It is the only HDSS conducting research on VL, which is a vector-borne infectious disease transmitted by female phlebotomine sandflies and is fatal if left untreated. Currently the HDSS serves a population of over 105,000 in 66 villages. The HDSS collects data on vital events including pregnancies, births, deaths, migration and marriages, as well as other socio-economic indicators, at regular intervals. Incident VL cases are identified. The HDSS team is experienced in conducting both qualitative and quantitative studies, sample collection and rapid diagnostic tests in the field. In each village, volunteers connect the HDSS team with the community members. The Muzaffarpur-TMRC HDSS provides opportunities for studies on VL and other neglected tropical diseases (NTDs) and their interaction with demographic events such as migration. Queries related to research collaborations and data sharing can be sent to Dr Shyam Sundar at [drshyamsundar@hotmail.com].
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Hasker E, Chourasia A, Malviya P, Gidwani K, Picado A, Ostyn B, Kansal S, Singh R, Singh O, Singh A, Wilson M, Khanal B, Rijal S, Boelaert M, Sundar S. Strong association between serological status and probability of progression to clinical visceral leishmaniasis in prospective cohort studies in India and Nepal. Int J Infect Dis 2014. [DOI: 10.1016/j.ijid.2014.03.940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Picado A, Ostyn B, Singh SP, Uranw S, Hasker E, Rijal S, Sundar S, Boelaert M, Chappuis F. Risk factors for visceral leishmaniasis and asymptomatic Leishmania donovani infection in India and Nepal. PLoS One 2014; 9:e87641. [PMID: 24498159 PMCID: PMC3909193 DOI: 10.1371/journal.pone.0087641] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 12/30/2013] [Indexed: 11/22/2022] Open
Abstract
There is increasing interest in the role of asymptomatic infection in transmission of Visceral Leishmaniasis (VL). We studied the individual, household and environmental factors associated with asymptomatic Leishmania donovani infected individuals and VL. 7,538 individuals living in VL endemic villages in India and Nepal were divided into three mutually exclusive groups based on their VL history and Direct Agglutination Test (DAT) results in yearly serosurveys over a two-year period. The groups were (1) VL cases, (2) asymptomatically infected individuals (seroconverters) and (3) seronegative individuals. VL cases and seroconverters were compared to seronegative individuals in mixed logistic regression models. The risk of seroconversion and disease was significantly increased in individuals aged 14 to 24 years old and by the presence of other DAT-positive, asymptomatically infected individuals and VL cases in the house. The risk of seroconversion was higher in Indian than in Nepalese villages and it increased significantly with age, but not so for VL. This study demonstrates that, when risk factors for leishmanial infection and VL disease are evaluated in the same population, epidemiological determinants for asymptomatic infection and VL are largely similar.
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Allepuz A, Stevenson M, Kivaria F, Berkvens D, Casal J, Picado A. Risk Factors for Foot-and-Mouth Disease in Tanzania, 2001-2006. Transbound Emerg Dis 2013; 62:127-36. [DOI: 10.1111/tbed.12087] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Indexed: 11/30/2022]
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Srivastava P, Gidwani K, Picado A, Van der Auwera G, Tiwary P, Ostyn B, Dujardin JC, Boelaert M, Sundar S. Molecular and serological markers of Leishmania donovani infection in healthy individuals from endemic areas of Bihar, India. Trop Med Int Health 2013; 18:548-54. [PMID: 23464581 DOI: 10.1111/tmi.12085] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Recent epidemiological reports indicate that asymptomatic human infections with Leishmania donovani, the causative agent of visceral leishmaniasis or Kala-azar (KA), occur frequently in India. We explored markers of infection. METHODS Blood samples were collected from 286 healthy subjects from 16 villages in the Muzaffarpur district of Bihar. These individuals were classified into three groups: (i) persons with no history of KA and living in a house where no KA cases were previously reported, (ii) persons with no history of KA but living in a house where KA cases were diagnosed at the time of sampling or in the past, and (iii) successfully treated KA patients. Each sample was tested using a Leishmania-specific PCR to detect Leishmania DNA, and two serological tests to demonstrate anti-Leishmania antibodies: the Direct Agglutination Test and rK39 ELISA. RESULTS PCR positivity was similar among the three groups (20-25%). In contrast, among treated patients, the percentage of serologically positive individuals was roughly five times that of healthy individuals with no KA history, as measured with either test. Living in a house where KA had been reported did not affect seropositivity. CONCLUSION A significant proportion of asymptomatic infections of Leishmania exist in endemic regions. Using a combination of molecular and serological tests increases the capacity to detect infections at different stages. Further work is required to understand the kinetics of the markers.
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Hasker E, Singh SP, Malaviya P, Picado A, Gidwani K, Singh RP, Menten J, Boelaert M, Sundar S. Visceral leishmaniasis in rural bihar, India. Emerg Infect Dis 2013; 18:1662-4. [PMID: 23017164 PMCID: PMC3471608 DOI: 10.3201/eid1810.111083] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
To identify factors associated with incidence of visceral leishmaniasis (VL), we surveyed 13,416 households in Bihar State, India. VL was associated with socioeconomic status, type of housing, and belonging to the Musahar caste. Annual coverage of indoor residual insecticide spraying was 12%. Increasing such spraying can greatly contribute to VL control.
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Hasker E, Kansal S, Malaviya P, Gidwani K, Picado A, Singh RP, Chourasia A, Singh AK, Shankar R, Menten J, Wilson ME, Boelaert M, Sundar S. Latent infection with Leishmania donovani in highly endemic villages in Bihar, India. PLoS Negl Trop Dis 2013; 7:e2053. [PMID: 23459501 PMCID: PMC3573094 DOI: 10.1371/journal.pntd.0002053] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 12/23/2012] [Indexed: 11/24/2022] Open
Abstract
Introduction Asymptomatic persons infected with the parasites causing visceral leishmaniasis (VL) usually outnumber clinically apparent cases by a ratio of 4–10 to 1. We describe patterns of markers of Leishmania donovani infection and clinical VL in relation to age in Bihar, India. Methods We selected eleven villages highly endemic for Leishmania donovani. During a 1-year interval we conducted two house to house surveys during which we collected blood samples on filter paper from all consenting individuals aged 2 years and above. Samples were tested for anti-leishmania serology by Direct Agglutination Test (DAT) and rK39 ELISA. Data collected during the surveys included information on episodes of clinical VL among study participants. Results We enrolled 13,163 persons; 6.2% were reactive to DAT and 5.9% to rK39. Agreement between the tests was weak (kappa = 0.30). Among those who were negative on both tests at baseline, 3.6% had converted to sero-positive on either of the two tests one year later. Proportions of sero-positives and sero-converters increased steadily with age. Clinical VL occurred mainly among children and young adults (median age 19 years). Discussion Although infection with L. donovani is assumed to be permanent, serological markers revert to negative. Most VL cases occur at younger ages, yet we observed a steady increase with age in the frequency of sero-positivity and sero-conversion. Our findings can be explained by a boosting effect upon repeated exposure to the parasite or by intermittent release of parasites in infected subjects from safe target cells. A certain proportion of sero-negative subjects could have been infected but below the threshold of antibody abundance for our serologic testing. In this study we assessed trends with age in the probability of being sero-positive or sero-converting for two serological markers of visceral leishmaniasis (VL) among asymptomatic residents of high incidence villages. As markers we used Direct Agglutination Test (DAT) and rK39 ELISA. We also compared titers among asymptomatic sero-positives with those of known recent VL cases among our study population. Infection with VL is assumed to be permanent, but sero-positivity is a temporary phenomenon. Though clinical VL was most common among children and young adults (median age 19 years), we observed a statistically significant increase with age in the probability of being sero-positive and in the probability of sero-converting. We also observed that the average antibody titers among asymptomatic sero-positives were much lower than those among recent clinical VL cases. The increase with age in the probability of being sero-positive but also in the probability of sero-conversion can be explained by subjects experiencing repeated episodes of sero-positivity. This could be due to a boosting effect upon re-exposure, or to internal release of parasites from safe target cells. The implication of our findings is that in VL endemic areas it will be difficult to reliably distinguish between infected and non-infected subjects.
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Picado A, Rijal S, Sundar S, Boelaert M. Visceral leishmaniasis treatment in the Indian subcontinent: how to reach the most vulnerable. Expert Rev Anti Infect Ther 2013; 10:839-41. [PMID: 23030320 DOI: 10.1586/eri.12.71] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Singh RP, Picado A, Alam S, Hasker E, Singh SP, Ostyn B, Chappuis F, Sundar S, Boelaert M. Post-kala-azar dermal leishmaniasis (PKDL) in visceral leishmaniasis-endemic communities in Bihar, India. Trop Med Int Health 2012:n/a-n/a. [PMID: 23279744 DOI: 10.1111/tmi.12044] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE: To assess the prevalence of Post-kala-azar dermal leishmaniasis (PKDL) in 16 visceral leishmaniasis-endemic communities in Bihar, India. METHODS: Three-stage house-to-house survey of 2020 households to identify and confirm PKDL cases. RESULTS: The prevalence of confirmed PKDL cases was 4.4 per 10 000 individuals and 7.8 if probable cases were also considered. The clinical history and treatment of the PKDL cases are discussed in detail. CONCLUSION: PKDL can develop in visceral leishmaniasis patients treated with different anti-leishmanial drugs. Migration of PKDL cases to other villages may expand visceral leishmaniasis-affected areas.
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Ballart C, Alcover MM, Picado A, Nieto J, Castillejo S, Portús M, Gállego M. First survey on canine leishmaniasis in a non classical area of the disease in Spain (Lleida, Catalonia) based on a veterinary questionnaire and a cross-sectional study. Prev Vet Med 2012; 109:116-27. [PMID: 23022112 DOI: 10.1016/j.prevetmed.2012.09.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 09/04/2012] [Accepted: 09/05/2012] [Indexed: 11/20/2022]
Abstract
The Spanish distribution of canine leishmaniasis (CanL) is heterogeneous and very few data are available for the north of the country, including the province of Lleida (Catalonia, Spain). This work describes the results obtained from a questionnaire sent to veterinarians throughout the province of Lleida. The majority of veterinarians (25/32, 78.1%) believed CanL cases were increasing and that the dogs had been infected locally (30/32, 93.8%). Also, a cross-sectional study was performed on the seroprevalence of CanL in kennel dogs, with and without compatible clinical signs, in the county of Pallars Sobirà (Pyrenees of Lleida), where an autochthonous case of CanL had been previously detected. Four serological tests were used (IFAT, ELISA, Western blot, ICF) and dogs that tested positive with at least two immunological methods were considered seropositive and probably infected. 33.1% (48/145) of the dogs were seropositive. The results of a mixed logistic regression model showed that the risk of seropositivity increased with age (OR=1.35, p-value=0.002), among dogs living in the southern part of Pallars Sobirà (OR=6.20, p-value=0.025) and among dogs whose owners considered their animals to be at risk of leishmaniasis infection (OR=1.26, p-value=0.024) and who were unaware of anti-sand fly preventive methods (OR=11.6, p-value=0.009). The risk decreased when dogs lived in an urban-periurban habitat (OR=0.17, p-value=0.002). The information gathered in the veterinary questionnaires helped us to define the knowledge, perception and awareness of the disease in a naïve region, supporting the hypothesis of an existing CanL focus in Pallars Sobirà, which was confirmed by the seroepidemiological survey. The seroprevalence study carried out on kennel dogs of local origin proved useful for detecting an autochthonous focus of leishmaniasis through the analysis of a small number of animals.
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Singh RP, Picado A, Alam S, Hasker E, Singh SP, Ostyn B, Chappuis F, Sundar S, Boelaert M. Post-kala-azar dermal leishmaniasis in visceral leishmaniasis-endemic communities in Bihar, India. Trop Med Int Health 2012; 17:1345-8. [PMID: 22882665 DOI: 10.1111/j.1365-3156.2012.03067.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We assessed the prevalence of post-kala-azar dermal leishmaniasis (PKDL), a late cutaneous manifestation of visceral leishmaniasis (VL), in 16 VL-endemic communities in Bihar, India. The prevalence of confirmed PKDL cases was 4.4 per 10 000 individuals and 7.8 if probable cases were also considered. The clinical history and treatment of the post-kala-azar dermal leishmaniasis cases are discussed.
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Picado A, Dash AP, Bhattacharya S, Boelaert M. Vector control interventions for visceral leishmaniasis elimination initiative in South Asia, 2005-2010. Indian J Med Res 2012; 136:22-31. [PMID: 22885260 PMCID: PMC3461713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The Visceral Leishmaniasis (VL) Elimination Initiative in the Indian subcontinent was launched in 2005 as a joint effort between the governments in the Region (India, Nepal and Bangladesh) and the World Health Organization (WHO). The objective is to reduce the annual VL incidence below 1/10,000 inhabitants by 2015 based on detection and treatment of VL cases and vector control. We present here a review of studies published in the period 2005-2010 on the efficacy of different tools to control Phlebotomus argentipes. The review indicates that the current indoor residual spraying (IRS) and novel vector control methods mainly insecticide treated nets (ITN) have low effectiveness for several reasons. Efforts to improve quality of IRS operations and further research on alternative and integrated vector control methods need to be promoted to reach the VL elimination target by 2015.
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Pascual Martínez F, Picado A, Roddy P, Palma P. Low castes have poor access to visceral leishmaniasis treatment in Bihar, India. Trop Med Int Health 2012; 17:666-73. [PMID: 22385129 DOI: 10.1111/j.1365-3156.2012.02960.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES Bihar, the poorest state in India, concentrates most of the visceral leishmaniasis (VL) cases in the country. A large proportion of the poor rural communities where VL is endemic are marginalized by their socio-economic status, intrinsically related to the caste system. In this study, we evaluated whether people from low socio-economic strata had difficulties accessing VL treatment in Bihar. As a secondary outcome, we evaluated whether people delaying their VL treatment had poorer clinical indicators at admission. METHODS Data on 2187 patients with VL treated by Médecins Sans Frontières (MSF) in Vaishali district from July 2007 to December 2008 were analysed. Patients who reported having onset of symptoms ≥8 weeks before admission were defined as 'late presenters'. Logistic regression models were used to evaluate whether low castes had higher risk to be 'late presenters' compared to the rest of castes and whether 'late presenters' had poorer indicators at admission (i.e. haemoglobin level, spleen size). RESULTS After adjusting for age, gender and distance to VL treatment facility, Mushars (the lowest caste in Bihar) had twice the odds to be 'late presenters' compared to the rest of castes (OR 2.05, 95% CI: 1.24-2.38). Subjects that had VL symptoms for ≥8 weeks had a larger spleen and lower haemoglobin level than those that were treated earlier. CONCLUSION Low castes have poor access to VL treatment in Bihar, and late presenters have poorer clinical indicators at admission. These findings have implications at individual and community levels and should stimulate targeted VL control programmes to ensure that marginalized communities in Bihar are properly treated.
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Das M, Roy L, Picado A, Kroeger A, Rijal S, Boelaert M. Deltamethrin and permethrin residue on long-lasting insecticidal nets after 18 months of use in a visceral leishmaniasis-endemic area in Nepal. Trans R Soc Trop Med Hyg 2012; 106:230-4. [PMID: 22381627 DOI: 10.1016/j.trstmh.2012.01.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2011] [Revised: 01/13/2012] [Accepted: 01/13/2012] [Indexed: 12/01/2022] Open
Abstract
The insecticide residue on two types of long-lasting insecticidal nets (LLIN), Olyset Net and PermaNet 2.0, used in a visceral leishmaniasis-endemic village in eastern Nepal was quantified using HPLC. After two washes during 18 months of use the mean insecticide residues on PermaNet 2.0 and Olyset Net were 53.5 mg/m(2) (97.3% of the target dose) of deltamethrin and 911.8 mg/m(2) (91.2% of the target dose) of permethrin, respectively. These residues were close to the insecticide loads specified by the manufacturers of the two LLINs. The use of LLINs has been postulated as an alternative or complementary method to indoor residual spraying. Our results suggest that LLINs should be washed 4-5 times each year throughout their lifespan by specifically requesting villagers to wash nets on certain dates. The insecticide residue on the nets and their bioefficacy against sand fly vectors should be monitored after each wash, in various cultural settings, to assess their durability and long-term retention of the insectide.
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Alcover MM, Gramiccia M, Di Muccio T, Ballart C, Castillejo S, Picado A, Portús M, Gállego M. Application of molecular techniques in the study of natural infection of Leishmania infantum vectors and utility of sandfly blood meal digestion for epidemiological surveys of leishmaniasis. Parasitol Res 2012; 111:515-23. [PMID: 22382204 DOI: 10.1007/s00436-012-2863-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 02/10/2012] [Indexed: 10/28/2022]
Abstract
Epidemiological studies on the distribution of leishmaniasis caused by Leishmania infantum Nicolle, 1908 (Kinetoplastida: Trypanosomatidae) have been based principally on serological surveys of the canine reservoir. This methodology is useful due to the facility of sampling, the rapidity in obtaining results, its consistency and because it allows the detection of heterogeneous foci of canine leishmaniasis (CanL) even in small areas. Other investigations have analysed Leishmania parasitism in sandflies (Diptera: Psychodidae: Phlebotominae) by using classical dissection techniques. These techniques allow the vector species to be incriminated in different foci, although they suffer from being very time consuming. Lately, studies in this field are increasingly using molecular techniques, which are faster and easier to perform. In the present work, we applied a nested-PCR in a study of natural infection of sandflies by Leishmania in three isolated farms where serological data on canine leishmaniasis of local dogs were also obtained. The analysis allowed the detection of 38.7% of females with positive nested-PCR (78%, 18% and 0%, respectively, in the different isolated farms). The positive Leishmania DNA samples were genotyped and identified as L. infantum. The results of this work provide new data for the vectorial capacity of Phlebotomus ariasi in a Pyrenean area, which can be considered at risk of becoming a new focus of CanL. The females with positive nested-PCR displayed blood in the midgut at different degrees of digestion, and/or were gravid. According to the multivariate logistic regression analysis, the risk of nested-PCR-positivity increased significantly with the degree of blood digestion (OR = 1.3; P value = 0.025). The Phlebotomus species and the presence of eggs were not statistically associated with nested-PCR positivity (P value of >0.05). The correlation of positive nested-PCR results with the presence of seropositive dogs in the farm confirms the utility of this technique in the study of the distribution and intensity of leishmaniasis foci. Also, the importance of sandfly blood-meal digestion for epidemiological surveys of leishmaniasis foci has been demonstrated.
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Picado A, Singh SP, Vanlerberghe V, Uranw S, Ostyn B, Kaur H, Das ML, Sundar S, Rijal S, Tungu P, Boelaert M, Rowland M. Residual activity and integrity of PermaNet® 2.0 after 24 months of household use in a community randomised trial of long lasting insecticidal nets against visceral leishmaniasis in India and Nepal. Trans R Soc Trop Med Hyg 2011; 106:150-9. [PMID: 22137191 DOI: 10.1016/j.trstmh.2011.10.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 10/18/2011] [Accepted: 10/18/2011] [Indexed: 10/14/2022] Open
Abstract
The World Health Organization (WHO) recommends several brands of long lasting insecticidal net (LN) for protection against insect vectors but also advises national programmes to monitor and evaluate performance under local conditions to help them select the most suitable LN for their setting. During the course of a community randomised trial of LNs against visceral leishmaniasis in northern India and Nepal, opportunity arose to assess the efficacy of PermaNet 2.0 (Vestergaard-Frandsen, Denmark) after two years of use against sandfly vectors. Between 63% (India) and 78% (Nepal) of LNs became holed over the course of two years, deltamethrin residues fell from 55 mg/m(2) to an average of 11.6 mg/m(2) (India) and 27.9 mg/m(2) (Nepal), but on the basis of bioassay criteria all LNs tested still met the WHO Pesticide Evaluation Scheme standard for LN effectiveness. Nets had on average only been washed 2.5 times (India) and 0.6 times (Nepal) by householders over the course of two years. The loss of insecticide was attributed to factors which had little or nothing to do with washing, such as handling, friction and torsion during daily use. Under conditions pertaining in this region of south Asia, and for two years at least, this brand of net continues to meet the criteria established by WHO for LNs.
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Khanal B, Rijal S, Ostyn B, Picado A, Gidwani K, Menten J, Jacquet D, Lejon V, Chappuis F, Boelaert M. Serological markers for leishmania donovani infection in Nepal: Agreement between direct agglutination test and rK39 ELISA. Trop Med Int Health 2011; 15:1390-4. [PMID: 21998875 DOI: 10.1111/j.1365-3156.2010.02631.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Visceral leishmaniasis (VL) is an important vector-borne disease caused by Leishmania donovani in the Indian subcontinent. The actual incidence and role of asymptomatic infections in the region are not wellknown. We used the direct agglutination test (DAT) and the rK39 ELISA as L. donovani infection markers in 10 VL endemic villages in Nepal. DAT titre distribution showed two subgroups in the population (infected and non-infected individuals), while rK39 did not. The agreement between both tests was moderate (j = 0.53; 95% CI 0.49–0.57). More research is needed to develop validated markers for Leishmania infection.
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Ostyn B, Gidwani K, Khanal B, Picado A, Chappuis F, Singh SP, Rijal S, Sundar S, Boelaert M. Incidence of symptomatic and asymptomatic Leishmania donovani infections in high-endemic foci in India and Nepal: a prospective study. PLoS Negl Trop Dis 2011; 5:e1284. [PMID: 21991397 PMCID: PMC3186756 DOI: 10.1371/journal.pntd.0001284] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Accepted: 07/05/2011] [Indexed: 11/18/2022] Open
Abstract
Incidence of Leishmania donovani infection and Visceral Leishmaniasis (VL) was assessed in a prospective study in Indian and Nepalese high-endemic villages. DAT-seroconversion was used as marker of incident infection in 3 yearly surveys. The study population was followed up to month 30 to identify incident clinical cases. In a cohort of 9034 DAT-negative individuals with neither active signs nor history of VL at baseline, 42 VL cases and 375 asymptomatic seroconversions were recorded in the first year, giving an infection:disease ratio of 8.9 to 1. In the 18 months' follow-up, 7 extra cases of VL were observed in the seroconverters group (N=375), against 14 VL cases among the individuals who had not seroconverted in the first year (N=8570) (RR=11.5(4.5<RR<28.3)). Incident asymptomatic L. donovani infection in VL high-endemic foci in India and Nepal is nine times more frequent than incident VL disease. About 1 in 50 of these new but latent infections led to VL within the next 18 months.
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