Epidemiological, Serological, and Entomological Investigation of New Visceral Leishmaniasis Foci in Nepal.

The aim of this study was to explore epidemiological, serological, entomological, and social aspects of visceral leishmaniasis (VL) in new foci in Nepal. The study was conducted in 11 villages of five districts that had been previously free of VL but that reported new cases between 2019 and 2021. We screened 1,288 inhabitants using rK39 tests and investigated the epidemiological and clinical characteristics of 12 recent VL cases. A total of 182 community members were interviewed about knowledge, attitude, and practices regarding VL. They then underwent an awareness training; 40 of them had a second interview at 6 months to assess the training impact. Vector surveys were conducted in six houses per village to assess sandfly density and infection rates. The prevalence of VL infection was 0.5% and 3.2% among screened populations in Dolpa and Kavre districts, respectively, while the other districts had no rK39-positive cases. No association between travel history and VL infection was found. Phlebotomus argentipes sandflies were collected in three districts at high altitudes (from 1,084 to 4,450 m). None of the sandflies captured had Leishmania donovani DNA. People in new foci were not aware of VL symptoms, vectors, or preventive measures. The training significantly improved their knowledge and practice in seeking medical care in case of illness. The epidemiological, serological, and entomological investigations suggest indigenous focal transmission of VL. An integrated package of strategic interventions should be implemented by the national VL elimination program in districts with new VL foci.

The ongoing risk of Leishmania donovani transmission in eastern Nepal: an entomological investigation during the elimination era.

BACKGROUND: Visceral leishmaniasis (VL), a life-threatening neglected tropical disease, is targeted for elimination from Nepal by the year 2026. The national VL elimination program is still confronted with many challenges including the increasingly widespread distribution of the disease over the country, local resurgence and the questionable efficacy of the key vector control activities. In this study, we assessed the status and risk of Leishmania donovani transmission based on entomological indicators including seasonality, natural Leishmania infection rate and feeding behavior of vector sand flies, Phlebotomus argentipes, in three districts that had received disease control interventions in the past several years in the context of the disease elimination effort. METHODS: We selected two epidemiologically contrasting settings in each survey district, one village with and one without reported VL cases in recent years. Adult sand flies were collected using CDC light traps and mouth aspirators in each village for 12 consecutive months from July 2017 to June 2018. Leishmania infection was assessed in gravid sand flies targeting the small-subunit ribosomal RNA gene of the parasite (SSU-rRNA) and further sequenced for species identification. A segment (~ 350 bp) of the vertebrate cytochrome b (cytb) gene was amplified from blood-fed P. argentipes from dwellings shared by both humans and cattle and sequenced to identify the preferred host. RESULTS: Vector abundance varied among districts and village types and peaks were observed in June, July and September to November. The estimated Leishmania infection rate in vector sand flies was 2.2% (1.1%-3.7% at 95% credible interval) and 0.6% (0.2%-1.3% at 95% credible interval) in VL and non-VL villages respectively. The common source of blood meal was humans in both VL (52.7%) and non-VL (74.2%) villages followed by cattle. CONCLUSIONS: Our findings highlight the risk of ongoing L. donovani transmission not only in villages with VL cases but also in villages not reporting the presence of the disease over the past several years within the districts having disease elimination efforts, emphasize the remaining threats of VL re-emergence and inform the national program for critical evaluation of disease elimination strategies in Nepal.

Follow-up assessment of visceral leishmaniasis treated patients and the impact of COVID-19 on control services in Nepal.

BACKGROUND: Follow-up assessment of visceral leishmaniasis (VL) treated cases is important to monitor the long term effectiveness of treatment regimens. The main objective of this study was to identify the gaps and challenges in the follow-up of treated VL cases, to monitor treatment outcome and to assess the impact of COVID-19 on VL elimination services and activities. METHODS: Clinicians treating VL patients, district focal persons for VL, and patients treated for VL in seven high endemic districts in Nepal during 2019-2022 were interviewed to collect data on challenges in the follow-up of VL treated patients as per national strategy. RESULTS: Follow up status was poor in two districts with the largest number of reported cases. The majority of cases were children under 10 years of age (44.2%). Among 104 VL treated cases interviewed, 60.6% mentioned that clinicians had called them for follow-up but only 37.5% had complied. Among 112 VL treated cases followed up, 8 (7.14%) had relapse and 2 (1.8%) had PKDL. Among 66 cases who had VL during the COVID-19 lock down period, 32 (48.5%) were diagnosed within 1 week; however, 10 (15.1%) were diagnosed only after 4 weeks or more. During the COVID-19 pandemic, there was no active search for VL because of budget constraints and lack of diagnostic tests, and no insecticide spraying was done. CONCLUSION: Relapses and PKDL are challenges for VL elimination and a matter of concern. Successful implementation of the national strategy for follow up of treated VL cases requires addressing elements related to patients (awareness, transport, communication) clinicians (compliance) and organization of service delivery (local health worker training and deployment). COVID-19 did not have much impact on VL diagnosis and treatment; however, public health programmes including active case detection and insecticide spraying for vector control were severely reduced.

Prevalence of post kala-azar dermal leishmaniasis (PKDL) and treatment seeking behavior of PKDL patients in Nepal.

BACKGROUND: In Nepal, the burden of post kala-azar dermal leishmaniasis (PKDL) is not known since there is no active case detection of PKDL by the national programme. PKDL patients could pose a challenge to sustain visceral leishmaniasis (VL) elimination. The objective of this study was to determine the prevalence of PKDL and assess PKDL patients' knowledge on VL and PKDL, and stigma associated with PKDL. METHODOLOGY/PRINCIPAL FINDINGS: Household surveys were conducted in 98 VL endemic villages of five districts that reported the highest number of VL cases within 2018-2021. A total of 6,821 households with 40373 individuals were screened for PKDL. Cases with skin lesions were referred to hospitals and examined by dermatologists. Suspected PKDL cases were tested with rK39 and smear microscopy from skin lesions. An integrated diagnostic approach was implemented in two hospitals with a focus on management of leprosy cases where cases with non-leprosy skin lesions were tested for PKDL with rK39. Confirmed PKDL patients were interviewed to assess knowledge and stigma associated with PKDL, using explanatory model interview catalogue (EMIC) with maximum score of 36. Among 147 cases with skin lesions in the survey, 9 (6.12%) were confirmed as PKDL by dermatologists at the hospital. The prevalence of PKDL was 2.23 per 10,000 population. Among these 9 PKDL cases, 5 had a past history of VL and 4 did not. PKDL cases without a past history of VL were detected among the "new foci", Surkhet but none in Palpa. None of the cases negative for leprosy were positive for PKDL. There was very limited knowledge of PKDL and VL among PKDL cases. PKDL patients suffered to some degree from social and psychological stigma (mean ± s.d. score = 17.89 ± 12.84). CONCLUSIONS/SIGNIFICANCE: Strengthening the programme in PKDL case detection and management would probably contribute to sustenance of VL elimination. Awareness raising activities to promote knowledge and reduce social stigma should be conducted in VL endemic areas.

Response to Visceral Leishmaniasis Cases through Active Case Detection and Vector Control in Low-Endemic Hilly Districts of Nepal.

The visceral leishmaniasis (VL) elimination program in Nepal has largely completed the attack phase and is moving toward consolidation and maintenance phases. New VL foci are, however, appearing in Nepal, and therefore new innovative community-centered strategies need to be developed and tested. We conducted early case detection by an index case-based approach and assessed the feasibility, efficacy, and cost of an intervention for sandfly control through indoor residual spraying (IRS) or insecticidal wall painting (IWP) in new and low-endemic districts Palpa and Surkhet. IRS was performed in 236 households and IWP in 178 households. We screened 1,239 and 596 persons in Palpa and Surkhet, respectively, resulting in the detection of one VL case in Palpa. Both IWP and IRS were well accepted, and the percentage reductions in sandfly density after 1, 9, and 12 months of intervention were 90%, 81%, and 75%, respectively, for IWP and 81%, 59%, and 63% respectively for IRS. The cost per household protected per year was USD 10.3 for IRS and 32.8 for IWP, although over a 2-year period, IWP was more cost-effective than IRS. Active case detection combined with sandfly control through IWP or IRS can support to VL elimination in the consolidation and maintenance phase.

Susceptibility status of the wild-caught Phlebotomus argentipes (Diptera: Psychodidae: Phlebotominae), the sand fly vector of visceral leishmaniasis, to different insecticides in Nepal.

BACKGROUND: Visceral leishmaniasis (VL) is targeted for elimination as a public health problem in Nepal by 2023. For nearly three decades, the core vector control intervention in Nepal has been indoor residual spraying (IRS) with pyrethroids. Considering the long-term use of pyrethroids and the possible development of resistance in the vector Phlebotomus argentipes sand flies, we monitored the susceptibility status of their field populations to the insecticides of different classes, in villages with and without IRS activities in recent years. METHODOLOGY/PRINCIPAL FINDINGS: Sand flies were collected from villages with and without IRS in five VL endemic districts from August 2019 to November 2020. The WHO susceptibility test procedure was adopted using filter papers impregnated at the discriminating concentrations of insecticides of the following classes: pyrethroids (alpha-cypermethrin 0.05%, deltamethrin 0.05%, and lambda-cyhalothrin 0.05%), carbamates (bendiocarb 0.1%) and organophosphates (malathion 5%). Pyrethroid resistance intensity bioassays with papers impregnated with 5× of the discriminating concentrations, piperonyl butoxide (PBO) synergist-pyrethroid bioassays, and DDT cross-resistance bioassays were also performed. In the IRS villages, the vector sand flies were resistant (mortality rate <90%) to alpha-cypermethrin and possibly resistant (mortality rate 90-97%) to deltamethrin and lambda-cyhalothrin, while susceptibility to these insecticides was variable in the non-IRS villages. The vector was fully susceptible to bendiocarb and malathion in all villages. A delayed knockdown time (KDT50) with pyrethroids was observed in all villages. The pyrethroid resistance intensity was low, and the susceptibility improved at 5× of the discriminating concentrations. Enhanced pyrethroid susceptibility after pre-exposure to PBO and the DDT-pyrethroid cross-resistance were evident. CONCLUSIONS/SIGNIFICANCE: Our investigation showed that P. argentipes sand flies have emerged with pyrethroid resistance, suggesting the need to switch to alternative classes of insecticides such as organophosphates for IRS. We strongly recommend the regular and systematic monitoring of insecticide resistance in sand flies to optimize the efficiency of vector control interventions to sustain VL elimination efforts in Nepal.

Housing structure including the surrounding environment as a risk factor for visceral leishmaniasis transmission in Nepal.

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.

Role of female community health volunteers for visceral leishmaniasis detection and vector surveillance in Nepal.

Background: As visceral leishmaniasis (VL) has recently expanded in previously non-endemic areas of Nepal, the health system is facing new challenges. Female community health volunteers(FCHVs) are playing an important role for VL elimination in Nepal. This study aimed to analyze the actual and potential role of FCHVs for VL elimination program as well as community awareness of the disease (VL) and protective measures. Methods: We used a concurrent embedded mixed methods design. Qualitative data were collected through in-depth interviews and focus group discussions with FCHVs of 22 VLendemic villages of 3 districts. Concurrently quantitative data were collected through formal interviews of 203 household heads of the same villages. Results: FCHVs are able to perform their duties in an efficient way with the support of their families and specific incentives. FCHVs in the VL-endemic region have a good ability to recognize the VL suspects and refer to health facilities. The feedback by the district health office on referred patients was weak thus missing the opportunity of involving FCHVs in the 6-months follow up. In houses with a previous VL case knowledge levels of prevention and treatment ofVL were significantly better than in houses without a previous VL case. More people in houses with a former VL patient were aware on VL transmission. Conclusion: FCHVs are playing an important role for VL elimination in Nepal through detection of suspected cases and referral and may play a role in vector surveillance.

Integrating Case Detection of Visceral Leishmaniasis and Other Febrile Illness with Vector Control in the Post-Elimination Phase in Nepal.

Nepal has completed the attack phase of visceral leishmaniasis (VL) elimination and now needs active case detection (ACD) and vector control methods that are suitable to the consolidation and maintenance phases. We evaluated different ACD approaches and vector control methods in Saptari district. We assessed 1) mobile teams deployed in villages with VL cases in 2015 to conduct combined camps for fever and skin lesions to detect VL/PKDL (post-kala-azar dermal leishmaniasis) and other infections; 2) an incentive approach by trained female community health volunteers (FCHVs) in villages with no VL cases in 2015. Both were followed by house-to-house visits. For vector control, four villages were randomly allocated to insecticide impregnation of bednets, insecticide wall painting, indoor residual spraying (IRS), and control. Sandfly density (by CDC light traps, The John W. Hock Company, USA) and mortality (World Health Organization cone bioassay) were assessed in randomly selected households. One VL, three tuberculosis, one leprosy, and one malaria cases were identified among 395 febrile cases attending the camps. Post-camp house-to-house screening involving 7,211 households identified 679 chronic fever and 461 skin lesion cases but no additional VL/PKDL. No VL/PKDL case was found by FCHVs. The point prevalence of chronic fever in camp and FCHV villages was 242 and 2 per 10,000 populations, respectively. Indoor residual spraying and bednet impregnation were effective for 1 month versus 12 months with insecticidal wall paint. Twelve-month sandfly mortality was 23%, 26%, and 80%, respectively, on IRS, bednet impregnation, and insecticide wall painting. In Nepal, fever camps and insecticidal wall paint prove to be alternative, sustainable strategies in the VL post-elimination program.

Barriers of Visceral Leishmaniasis reporting and surveillance in Nepal: comparison of governmental VL-program districts with non-program districts.

OBJECTIVES: At the time when Nepal is on the verge of reaching the maintenance phase of the Visceral Leishmaniasis (VL) elimination program, the country is facing new challenges. The disease has expanded to 61 of the country's 75 districts including previously non-endemic areas where there is no control or patient management program in place. This study aimed to assess which elements of the surveillance and reporting systems need strengthening to identify cases at an early stage, prevent further transmission and ensure sustained VL elimination. METHODS: In a cross-sectional mixed-method study, we collected data from two study populations in VL program and non-program districts. From February to May 2016, structured interviews were conducted with 40 VL patients, and 14 in-depth and semi-structured interviews were conducted with health managers. RESULTS: The median total delay from onset of symptoms to successful reporting to the Ministry of Health was 68.5 days in the VL-program and 83 days in non-program districts. The difference in patient's delay from the onset of symptoms to seeking health care was 3 days in VL-program and 20 days in non-program districts. The diagnostic delay (38.5 days and 36 days, respectively), treatment delay (1 vs. 1 days) and reporting delay (45 vs. 36 days) were similar in program and non-program districts. The diagnostic delay increased three-fold from 2012, while treatment and reporting delay remained unchanged. The main barriers to surveillance were: (i) lack of access and awareness in non-program districts; (ii) growing private sector not included in and not participating to referral, treatment and reporting; (iii) lack of cooperation and coordination among stakeholders for training and deployment of interventions; (iv) insufficient validation, outreach and process optimisation of the reporting system. CONCLUSIONS: Corrective measures are needed to maintain the achievements of the VL elimination campaign and prevent resurgence of the disease in Nepal. A clear patient referral structure, reinforcement of report notification and validation and direct relay of data by local hospitals and the private sector to the district health offices are needed to ensure prompt treatment and timely and reliable information to facilitate a responsive system of interventions.

Susceptibility of field-collected Phlebotomus argentipes (Diptera: Psychodidae) sand flies from Bangladesh and Nepal to different insecticides.

BACKGROUND: The sand fly Phlebotomus argentipes is the vector for visceral leishmaniasis (VL) in the Indian sub-continent. In Bangladesh since 2012, indoor residual spraying (IRS) was applied in VL endemic areas using deltamethrin. In Nepal, IRS was initiated in 1992 for VL vector control using lambda-cyhalothrin. Irrational use of insecticides may lead to vector resistance but very little information on this subject is available in both countries. The objective of this study was to generate information on the susceptibility of the vector sand fly, P. argentipes to insecticide, in support of the VL elimination initiative on the Indian sub-continent. METHODS: Susceptibility tests were performed using WHO test kits following the standard procedures regarding alpha cypermethrin (0.05%), deltamethrin (0.05%), lambda-cyhalothrin (0.05%), permethrin (0.75%), malathion (5%) and bendiocarb (0.1%) in six upazilas (sub-districts) in Bangladesh. In Nepal, the tests were performed for two insecticides: alpha cypermethrin (0.05%) and deltamethrin (0.05%). Adult P. argentipes sand flies were collected in Bangladesh from six VL endemic upazilas (sub-districts) and in Nepal from three endemic districts using manual aspirators. RESULTS: The results show that VL vectors were highly susceptible to all insecticides at 60 minutes of exposure in both countries. In Bangladesh, corrected mortality was 100% at 15 minutes as well as 30 minutes of exposure. The study sites in Nepal, however, showed some diverse results, with a mortality rate less than 90% for 15 minutes of exposure with alpha cypermethrin and deltamethrin in two districts but was above 95% after 30 minutes of exposure. CONCLUSIONS: These results suggest that the insecticides tested can still be used in the national programmes of Bangladesh and Nepal. However, insecticide rotation should be performed to mitigate the possible development of insecticide resistance. Periodic susceptibility tests should be performed by the countries to get timely alerts regarding insecticide resistance.

Entomological efficacy of durable wall lining with reduced wall surface coverage for strengthening visceral leishmaniasis vector control in Bangladesh, India and Nepal.

BACKGROUND: New methods for controlling sand fly are highly desired by the Visceral Leishmaniasis (VL) elimination program of Bangladesh, India and Nepal for its consolidation and maintenance phases. To support the program we investigated safety, efficacy and cost of Durable Wall Lining to control sand fly. METHODS: This multicentre randomized controlled study in Bangladesh, India and Nepal included randomized two intervention clusters and one control cluster. Each cluster had 50 households except full wall surface coverage (DWL-FWSC) cluster in Nepal which had 46 households. Ten of 50 households were randomly selected for entomological activities except India where it was 6 households. Interventions were DWL-FWSC and reduced wall surface coverage (DWL-RWSC) with DWL which covers 1.8 m and 1.5 m height from floor respectively. Efficacy was measured by reduction in sand fly density by intervention and sand fly mortality assessment by the WHO cone bioassay test at 1 month after intervention. Trained field research assistants interviewed household heads for socio-demographic information, knowledge and practice about VL, vector control, and for their experience following the intervention. Cost data was collected using cost data collection tool which was designed for this study. Statistical analysis included difference-in-differences estimate, bivariate analysis, Poisson regression model and incremental cost-efficacy ratio calculation. RESULTS: Mean sand fly density reduction by DWL-FWSC and DWL-RWSC was respectively -4.96 (95 % CI, -4.54, -5.38) and -5.38 (95 % CI, -4.89, -5.88). The sand fly density reduction attributed by both the interventions were statistically significant after adjusting for covariates (IRR = 0.277, p < 0.001 for DWL-RWSC and IRR = 0.371, p < 0.001 for DWL-FWSC). The efficacy of DWL-RWSC and DWL-FWSC on sand fly density reduction was statistically comparable (p = 0.214). The acceptability of both interventions was high. Transient burning sensations, flash on face and itching were most common adverse events and were observed mostly in Indian site. There was no serious adverse event. DWL-RWSC is cost-saving compared to DWL-FWSC. The incremental cost-efficacy ratio was -6.36, where DWL-RWSC dominates DWL-FWSC. CONCLUSIONS: DWL-RWSC intervention is safe, efficacious, cost-saving and cost-effective in reducing indoor sand fly density. The VL elimination program in the Indian sub-continent may consider DWL-RWSC for sand fly control for its consolidation and maintenance phases.

Efficacy, Safety and Cost of Insecticide Treated Wall Lining, Insecticide Treated Bed Nets and Indoor Wall Wash with Lime for Visceral Leishmaniasis Vector Control in the Indian Sub-continent: A Multi-country Cluster Randomized Controlled Trial.

BACKGROUND: We investigated the efficacy, safety and cost of lime wash of household walls plus treatment of sand fly breeding places with bleach (i.e. environmental management or EM), insecticide impregnated durable wall lining (DWL), and bed net impregnation with slow release insecticide (ITN) for sand fly control in the Indian sub-continent. METHODS: This multi-country cluster randomized controlled trial had 24 clusters in each three sites with eight clusters per high, medium or low sand fly density stratum. Every cluster included 45-50 households. Five households from each cluster were randomly selected for entomological measurements including sand fly density and mortality at one, three, nine and twelve months post intervention. Household interviews were conducted for socioeconomic information and intervention acceptability assessment. Cost for each intervention was calculated. There was a control group without intervention. FINDINGS: Sand fly mortality [mean and 95%CI] ranged from 84% (81%-87%) at one month to 74% (71%-78%) at 12 months for DWL, 75% (71%-79%) at one month to 49% (43%-55%) at twelve months for ITN, and 44% (34%-53%) at one month to 22% (14%-29%) at twelve months for EM. Adjusted intervention effect on sand fly density measured by incidence rate ratio ranged from 0.28 (0.23-0.34) at one month to 0.62 (0.51-0.75) at 12 months for DWL; 0.72 (0.62-0.85) at one month to 1.02 (0.86-1.22) at 12 months for ITN; and 0.89 (0.76-1.03) at one months to 1.49 (1.26-1.74) at 12 months for EM. Household acceptance of EM was 74% compared to 94% for both DWL and ITN. Operational cost per household in USD was about 5, 8, and 2 for EM, DWL and ITN, respectively. Minimal adverse reactions were reported for EM and ITN while 36% of households with DWL reported transient itching. INTERPRETATION: DWL is the most effective, durable and acceptable control method followed by ITN. The Visceral Leishmaniasis (VL) Elimination Program in the Indian sub-continent should consider DWL and ITN for sand fly control in addition to IRS.

Implication of vector characteristics of Phlebotomus argentipes in the kala-azar elimination programme in the Indian sub-continent.

BACKGROUND: Visceral leishmaniasis (VL), also known as kala-azar in the Indian sub-continent (ISC), is a major public health concern in Bangladesh, India, and Nepal, where it is caused by Leishmania donovani transmitted by the sand fly Phlebotomus argentipes. Various ecological parameters including air temperature, rainfall, wind speed, relative humidity, soil moisture, pH, and organic carbon are known to influence the oviposition of female sand flies, as well as the survival and development of larvae. However, more detailed knowledge on vector behavior, such as biting times, breeding places, and preferred hosts are needed to design optimal evidence-based vector control interventions. METHODS: In order to facilitate rational decisions regarding VL vector control, a systematic review was conducted to identify the prevailing practice and knowledge gaps in relation to vector bionomics and behavior. Search terms included 'sand fly bionomics', 'habitat', and 'visceral leishmaniasis/kala-azar vector control' using the Boolean operator AND to identify the country of interest, namely: Bangladesh, India, and Nepal. Both PubMed and Google search engines were used. Additional unpublished documents in the three countries were also analyzed. RESULTS: Information on the life cycle of VL vectors, their breeding behavior, infection rate with L. donovani, feeding behavior, and seasonal variation are useful for designing vector control operations. Unfortunately, none of the studies on the life cycle of P. argentipes was conducted in field settings of the ISC, so the publications from other locations had to be used for determining the duration of life cycle and development from egg to adult. However, information about breeding places, seasonal variation of vector densities, and 47 out of the selected 51 papers are available from the ISC and can be used for intelligent design of control operations. CONCLUSION: Vector control services should undertake routine insecticide resistance monitoring and adapt indoor residual spraying rounds to the seasonality of vector densities. Further research is needed on potential animal reservoirs for L. donovani, on the breeding habitat, and life cycle of sand flies in the ISC.

Ganglioneuroblastoma: Unusual presentation as a pleural mass mimicking mesothelioma.

Ganglioneuroblastoma (GNB) is a rare peripheral neuroblastic tumor that is derived from developing neuronal cells of the sympathetic nervous system, and usually occurs in young children. We present a case of GNB occurring as pleural mass in a 2-year-old boy, which led to diagnostic confusion. On fine-needle aspiration cytology (FNAC), it was misinterpreted as mesothelioma. He underwent thoracotomy with excision of the mass. Histopathological findings showed features of a biphasic tumor suggestive of mesothelioma. Immunohistochemistry (IHC) performed for mesothelioma markers were inconclusive. On review of the histology slides, GNB was considered, which was subsequently proven by IHC. The rarity of this tumor, along with its nearly restricted occurrence at a young age, necessitates a strong suspicion in patients presenting with a symptomatic intrathoracic mass.

Transmission of Leishmania donovani in the Hills of Eastern Nepal, an Outbreak Investigation in Okhaldhunga and Bhojpur Districts.

BACKGROUND: In the Indian subcontinent, Visceral leishmaniasis is endemic in a geographical area coinciding with the Lower Gangetic Plain, at low altitude. VL occurring in residents of hill districts is therefore often considered the result of Leishmania donovani infection during travel. Early 2014 we conducted an outbreak investigation in Okhaldhunga and Bhojpur districts in the Nepal hills where increasing number of VL cases have been reported. METHODOLOGY/PRINCIPAL FINDINGS: A house-to-house survey in six villages documented retrospectively 35 cases of Visceral Leishmaniasis (VL). Anti-Leishmania antibodies were found in 22/23 past-VL cases, in 40/416 (9.6%) persons without VL and in 12/155 (7.7%) domestic animals. An age- and sex- matched case-control study showed that exposure to known VL-endemic regions was no risk factor for VL, but having a VL case in the neighbourhood was. SSU-rDNA PCR for Leishmania sp. was positive in 24 (5%) of the human, in 18 (12%) of the animal samples and in 16 (14%) bloodfed female Phlebotomus argentipes sand flies. L. donovani was confirmed in two asymptomatic individuals and in one sand fly through hsp70-based sequencing. CONCLUSIONS/SIGNIFICANCE: This is epidemiological and entomological evidence for ongoing local transmission of L. donovani in villages at an altitude above 600 meters in Nepal, in districts considered hitherto non-endemic for VL. The VL Elimination Initiative in Nepal should therefore consider extending its surveillance and control activities in order to assure VL elimination, and the risk map for VL should be redesigned.

Feasibility of a combined camp approach for vector control together with active case detection of visceral leishmaniasis, post kala-azar dermal leishmaniasis, tuberculosis, leprosy and malaria in Bangladesh, India and Nepal: an exploratory study.

BACKGROUND: We assessed the feasibility and results of active case detection (ACD) of visceral leishmaniasis (VL), post kala-azar dermal leishmaniasis (PKDL) and other febrile diseases as well as of bednet impregnation for vector control. METHODS: Fever camps were organized and analyzed in twelve VL endemic villages in Bangladesh, India, and Nepal. VL, PKDL, tuberculosis, malaria and leprosy were screened among the febrile patients attending the camps, and existing bednets were impregnated with a slow release insecticide. RESULTS: Among the camp attendees one new VL case and two PKDL cases were detected in Bangladesh and one VL case in Nepal. Among suspected tuberculosis cases two were positive in India but none in the other countries. In India, two leprosy cases were found. No malaria cases were detected. Bednet impregnation coverage during fever camps was more than 80% in the three countries. Bednet impregnation led to a reduction of sandfly densities after 2 weeks by 86% and 32%, and after 4 weeks by 95% and 12% in India and Nepal respectively. The additional costs for the control programmes seem to be reasonable. CONCLUSION: It is feasible to combine ACD camps for VL and PKDL along with other febrile diseases, and vector control with bednet impregnation.

Do Size and Insecticide Treatment Matter? Evaluation of Different Nets against Phlebotomus argentipes, the Vector of Visceral Leishmaniasis in Nepal.

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.