Dataset Information

Molecular evidence supports the expansion of visceral leishmaniasis towards non-program districts of Nepal.

ABSTRACT: BACKGROUND:Visceral Leishmaniasis (VL) is caused by a protozoan parasite Leishmania donovani that is transmitted to humans by an infected female sandfly, Phlebotomus argentipes. VL is common in the Indian sub-continent including Nepal and efforts for its elimination are ongoing. However, expansion of disease towards the higher altitude areas, previously considered as VL free in Nepal, may impact the ability to achieve the elimination target by 2020. METHODS:This was an exploratory study, where VL suspected patients living exclusively in the non-program districts of Nepal and presenting with fever >?2?weeks and splenomegaly was included. The patients' blood samples were collected, and DNA was extracted. DNA was subjected to PCR amplification and subsequent sequencing. Additionally, past 10?years data of VL cases from the national databases were analysed to see the trends of the disease in program and non program districts. RESULTS:Analysis of the past 10?years data revealed that trend of VL cases significantly decreased in the program districts (p?=?0.001) while it increased in the non-program districts (p?=?0.002). The national trend for overall incidence of VL also significantly decreased over this time period. Limited number of patients' samples (n?=?14) were subjected to molecular investigation, and four patients were found to be positive for Leishmania species by PCR. Interestingly, these cases in non-program districts were indeed also L. donovoni complex. All four patients were male with age ranges from 10 to 68?years. GenBank BLAST of the obtained DNA sequences confirmed identified specimens as L. donovani complex. We identified additional VL cases from non-program districts (including the high lands) of Nepal, indicating that the infection could be an emerging threat for the non-program areas of Nepal. CONCLUSION:The demonstration of VL cases in areas initially considered non-endemic has raised concern about on-going transmission in those regions and may trigger subsequent government plan and action to include those areas in the elimination program. Thus, the government should consider revising the disease control programs to accommodate non-program districts for achieving the VL elimination goal set for 2020.

SUBMITTER: Shrestha M

PROVIDER: S-EPMC6528229 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature

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Molecular evidence supports the expansion of visceral leishmaniasis towards non-program districts of Nepal.

Shrestha Mitesh M Khatri-Chhetri Medha M Poudel Ram Chandra RC Maharjan Jyoti J Dumre Shyam Prakash SP Manandhar Krishna Das KD Pandey Basu Dev BD Pun Sher Bahadur SB Pandey Kishor K

BMC infectious diseases 20190521 1

<h4>Background</h4>Visceral Leishmaniasis (VL) is caused by a protozoan parasite Leishmania donovani that is transmitted to humans by an infected female sandfly, Phlebotomus argentipes. VL is common in the Indian sub-continent including Nepal and efforts for its elimination are ongoing. However, expansion of disease towards the higher altitude areas, previously considered as VL free in Nepal, may impact the ability to achieve the elimination target by 2020.<h4>Methods</h4>This was an exploratory ...[more]

PMID: 31113385

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Project description:BackgroundThe VL elimination strategy requires cost-effective tools for case detection and management. This intervention study tests the yield, feasibility and cost of 4 different active case detection (ACD) strategies (camp, index case, incentive and blanket approach) in VL endemic districts of India, Nepal and Bangladesh.Methodology/principal findingsFirst, VL screening (fever more than 14 days, splenomegaly, rK39 test) was performed in camps. This was followed by house to house screening (blanket approach). An analysis of secondary VL cases in the neighborhood of index cases was simulated (index case approach). A second screening round was repeated 4-6 months later. In another sub-district in India and Nepal, health workers received incentives for detecting new VL cases over a 4 month period (incentive approach). This was followed by house screening for undetected cases. A total of 28 new VL cases were identified by blanket approach in the 1(st) screening round, and used as ACD gold standard. Of these, the camp approach identified 22 (sensitivity 78.6%), index case approach identified 12 (sensitivity--42.9%), and incentive approach identified 23 new VL cases out of 29 cases detected by the house screening (sensitivity--79.3%). The effort required to detect a new VL case varied (blanket approach--1092 households, incentive approach--978 households; index case approach--788 households had to be screened). The cost per new case detected varied (camp approach $21 - $661; index case approach $149 - $200; incentive based approach $50 - $543; blanket screening $112 - $629). The 2(nd) screening round yielded 20 new VL cases. Sixty and nine new PKDL cases were detected in the first and second round respectively.Conclusions/significanceACD in the VL elimination campaign has a high yield of new cases at programme costs which vary according to the screening method chosen. Countries need the right mix of approaches according to the epidemiological profile, affordability and organizational feasibility.

Project description:Visceral leishmaniasis (VL) in Nepal is found in 61 out of 75 districts including areas previously listed as non- endemic. This study focused on the role of housing conditions and its immediate environment in VL transmission, to limit future transmissions, ensure sustainable vector control and support the VL elimination program. The objective was to explore the risk factors in rural housing-and land lot typologies contributing to clinical VL occurrence and transmission. Housing structures and land lots were examined based on characteristics as risk factors of VL transmission in a case-control analysis. VL cases from 2013-2017 were identified based on the existing database from the Epidemiology and Disease Control Division and District Public Health Office from the plain Terai area (Morang, and Saptari districts) and hilly area (Palpa district) of Nepal. Two hundred and three built environments were analyzed (66 cases and 137 controls). Inferential statistics and logistic regression analysis were performed to determine the association of risk factors with VL. The risk factors with the highest odds of VL were: bamboo walls (adjusted odds ratio (AOR)- 8.1, 95% CI 2.40-27.63, p = 0.001), walls made of leaves/branches (AOR- 3.0, 95% CI 0.84-10.93, p = 0.090), cracks in bedroom walls (AOR- 2.9, 95% CI 0.93-9.19, p = 0.065), and placing sacks near sleeping areas (AOR- 19.2, 95% CI 4.06-90.46, p <0.001). Significant outdoor factors were: lots with Kadam trees (AOR- 12.7, 95% CI 3.28-49.09, p <0.001), open ground-outdoor toilets (AOR- 9.3, 95% CI 2.14-369.85, p = 0.003), moisture in outdoor toilet sheds (AOR- 18.09, 95% CI 7.25-451.01, p = 0.002), nearby- open land (AOR- 36.8, 95% CI 3.14-430.98, p = 0.004), moisture inside animal sheds (AOR- 6.9, 95% CI 1.82-26.66, p = 0.005), and surrounding animals/animals wastes particularly goats (AOR- 3.5, 95% CI 1.09-10.94, p = 0.036). Certain housing and surrounding environmental conditions and characteristics are risk factors for VL. Hence, elimination and educational programs should include the focus on housing improvement and avoidance of risk factors. Longitudinal interventional studies are required to document temporal relationships and whether interventions on these factors will have an impact on Leishmania transmission or burden.

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Molecular evidence supports the expansion of visceral leishmaniasis towards non-program districts of Nepal.

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Molecular evidence supports the expansion of visceral leishmaniasis towards non-program districts of Nepal.

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