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Background: Understanding and improving the durability of long-lasting insecticidal nets (LLINs) in the field are critical for planning future implementation strategies including behavioral change for care and maintenance. LLIN distribution at high coverage is considered to be one of the adjunctive transmission reduction strategies in Nepal's Malaria Strategic Plan 2014-2025. The main objective of this study was to assess the durability through assessment of community usage, physical integrity, residual bio-efficacy, and chemical retention in LLINs: Interceptor®, Yorkool®, and PermaNet ®2.0 which were used in Nepal during 2009 through 2013., Methods: Assessments were conducted on random samples ( n = 440) of LLINs from the eleven districts representing four ecological zones: Terai plain region (Kailali and Kanchanpur districts), outer Terai fluvial ecosystem (Surkhet, Dang, and Rupandhei districts), inner Terai forest ecosystem (Mahhothari, Dhanusa, and Illam districts), and Hills and river valley (Kavrepalanchock and Sindhupalchok districts). For each LLIN, fabric integrity in terms of proportionate hole index (pHI) and residual bio-efficacy were assessed. However, for chemical retention, a representative sample of 44 nets (15 Yorkool®, 10 Permanet®2.0, and 19 Interceptor®) was evaluated. Data were analyzed using descriptive statistics stratified by LLINs brand, districts, and duration of exposure., Results: On average, duration of use of LLINs was shortest for the Yorkool® samples, followed by PermaNet® 2.0 and Interceptor® with median ages of 8.9 (IQR = 0.4), 23.8 (IQR = 3.2), and 50.1 (IQR = 3.2) months, respectively. Over 80% of field distributed Yorkool® and PermaNet® 2.0 nets were in good condition (pHI< 25) compared to Interceptor® (66%). Bio-efficacy analysis showed that average mortality rates of Interceptor and Yorkool were below World Health Organization (WHO) optimal effectiveness of ≥ 80% compared to 2-year-old PermaNet 2.0 which attained 80%. Chemical retention analysis was consistent with bio-efficacy results., Conclusion: This study shows that distribution of LLINs is effective for malaria control; however, serviceable life of LLINs should be considered in terms of waning residual bio-efficacy that warrants replacement. As an adjunctive malaria control tool, National Malaria Control Program of Nepal can benefit by renewing the distribution of LLINs in an appropriate time frame in addition to utilizing durable and effective LLINs., Competing Interests: Competing interestsThe authors declare that they have no competing interests., (© The Author(s) 2020.)

Background: A significant reduction in malaria cases over the recent years in Nepal has encouraged the government to adopt a goal of "malaria-free nation by 2025." Nevertheless, to achieve this goal, it is critical to identify the epidemiological burden of malaria by specific regions and areas for an effective targeted intervention. The main objective of this study was to estimate the risk of malaria at Village Development Committee (VDC) level in Nepal based on disease, vector, parasite, and geography., Methods: In 2012, the micro-stratification of malaria risk was carried out in 75 districts of Nepal. Instruments such as a questionnaire, case record forms, and guidelines for malaria micro-stratification were developed and pre-tested for necessary adaptations. Village Development Committee (VDC)-wise malaria data were analyzed using exploratory statistics and were stratified by geographical variables that contributed to the risk of malaria. To understand the transmission risk at VDC level, overlay analysis was done using ArcGIS 10. To ensure transparent, reproducible, and comprehensible risk assessment, standard scoring method was selected and utilized for data from 2009 to 2011. Thus identified, three major variables (key determinants) were given weights (wt.) accordingly to stratification of the malaria risk (disease burden, "0.3" wt.; ecology/vector transmission, "0.5" wt.; and vulnerability-population movement, "0.2" wt.). Malaria risk in a VDC was determined based on the overall scores and classified into four categories: no risk, low risk, moderate risk, and high risk., Results: Analyzing the overall risk based on scoring of the total VDCs ( n  = 3976), 54 (1.36%), 201 (5.06%), 999 (25.13%), and 2718 (68.36%) were identified as high-, moderate-, low-, and no-risk categories for malaria, respectively. Based on the population statistics, 3.62%, 9.79%, 34.52%, and 52.05% of the country's total population live in high-risk, moderate-risk, low-risk, and no-risk VDCs for malaria, respectively. Our micro-stratification study estimates are 100,000 population at high risk. Regional distribution showed that the majority of the high-risk VDCs were identified in the Far- and Mid-western regions (19 and 18 VDCs) followed by Central and Western regions (10 and 7 VDCs) with no high-risk VDCs in the Eastern region. Similarly, 77, 59, 27, 24, and 14 VDCs of the Central, Mid-western, Western, Eastern, and Far-western regions, respectively, were found under moderate malaria risk. Of the low-risk VDCs, 353, 215, 191, 148, and 92 were respectively from the Central, Eastern, Western, Far-western, and Mid-western regions., Conclusions: The current micro-stratification study provides insights on malaria risk up to the VDC level. This will help the malaria elimination program to target interventions at the local level thereby ensuring the best utilization of available resources to substantially narrowed-down target areas. With further updates and refinement, the micro-stratification approach can be employed to identify the risk areas up to smaller units within the VDCs (ward and villages)., Competing Interests: This study utilized a retrospective analysis of data collected as a part of National Malaria Control and elimination strategy. Additionally, since this study does not include any data directly related to human subjects, the study was exempted for ethical permissions. This was a national study, and taken approval from Epidemiology and Diseases Control Division, Department of Health services, Ministry of Health and Population, government of Nepal.Not applicable.The authors declare that they have no competing interests.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Background: The national treatment guidelines of Nepal have adopted Artemisinin Combination Therapies (ACTs) for the treatment of uncomplicated falciparum malaria since 2004. Emergence of Artemisinin resistance in the Greater Mekong Sub-region (GMS) and beyond may become a threat for Nepal as well. The main objective of this study was to assess the therapeutic efficacy of antimalarial drug artemether-lumefantrine in uncomplicated P. falciparum infected patients at health centers/hospitals treated over the period of 2 years (2013-2014)., Methods: Giemsa stained thick and thin smears, prepared from uncomplicated falciparum malaria patients who visited the selected sentinel sites in Nepal during 2013 to 2014 and met the inclusion criteria that included parasitemia (1000-10,000 /μL of blood), were evaluated until 28 days after ACTs treatment, following a World Health Organization (WHO) therapeutic efficacy protocol. Based on the re-occurrence of fever and resurge in parasitemia, the study patients were classified as resistant or susceptible. Blood specimens on filter papers were further analyzed by Polymerase Chain Reaction (PCR), specifically for the K13 propeller gene mutation (a recently identified molecular marker for ACT resistance)., Results: A total of 56,013 suspected malaria cases were screened for this study. Of which, 120 (0.21%) were infected with falciparum malaria. Out of 120, 28 cases of P. falciparum ( 28/120; 23.33%) were enrolled in the study, of which 24 cases completed the post-treatment follow up for 28 days. Only one case out of 24 (4%) was identified as a late treatment failure (LTF). K13 mutation, a proxy indicator for ACT resistance in parasites, was not detected on the day 1, which indicates resistance had not yet reached the molecular level., Conclusion: Only one case of late treatment failure was identified in this study. ACT combination using artemether-lumefantrine was still effective for the treatment of uncomplicated falciparum malaria in Nepal. A close monitoring and supervision for ACT resistance is essential for future malaria treatment in Nepal., Competing Interests: Ethical approval was obtained from the ethics review committee of Nepal Health Research Council (NHRC). A written informed consent was obtained from each participant for the study.Not ApplicableThe authors declare that they have no competing interests.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Background: Glucose-6-phosphate dehydrogenase (G6PD) is a rate limiting enzyme of the pentose phosphate pathway and is closely associated with the haemolytic disorders among patients receiving anti-malarial drugs, such as primaquine. G6PD deficiency (G6PDd) is an impending factor for radical treatment of malaria which affects the clearance of gametocytes from the blood and subsequent delay in the achievement of malaria elimination. The main objective of this study was to assess the prevalence of G6PD deficiency in six malaria endemic districts in Southern Nepal., Methods: A cross-sectional population based prevalence survey was conducted in six malaria endemic districts of Nepal, during April-Dec 2013. A total of 1341 blood samples were tested for G6PDd using two different rapid diagnostic test kits (Binax-Now ® and Care Start™). Equal proportions of participants from each district (n ≥ 200) were enrolled considering ethnic and demographic representation of the population groups., Results: Out of total 1341 blood specimens collected from six districts, the overall prevalence of G6PDd was 97/1341; 7.23% on Binax Now and 81/1341; 6.0% on Care Start test. Higher prevalence was observed in male than females [Binax Now: male 10.2%; 53/521 versus female 5.4%; 44/820 (p = 0.003) and Care Start: male 8.4%; 44/521 versus female 4.5%; 37/820 (p = 0.003)]. G6PDd was higher in ethnic groups Rajbanshi (11.7%; 19/162) and Tharu (5.6%; 56/1005) (p = 0.006), major inhabitant of the endemic districts. Higher prevalence of G6PDd was found in Jhapa (22/224; 9.8%) and Morang districts (18/225; 8%) (p = 0.031). In a multivariate analysis, male were found at more risk for G6PDd than females, on Binax test (aOR = 1.97; CI 1.28-3.03; p = 0.002) and Care Start test (aOR = 1.86; CI 1.16-2.97; p = 0.009)., Conclusions: The higher prevalence of G6PDd in certain ethnic group, gender and geographical region clearly demonstrates clustering of the cases and ascertained the risk groups within the population. This is the first study in Nepal which identified the vulnerable population groups for G6PDd in malaria endemic districts. The finding of this study warrants the need for G6PDd testing in vulnerable population groups in endemic districts, and also facilitates use of primaquine in mass supporting timely progress for malaria elimination.

Background: Recent gains in reducing the global burden of malaria are threatened by the emergence of Plasmodium falciparum resistance to artemisinins. The discovery that mutations in portions of a P. falciparum gene encoding kelch (K13)-propeller domains are the major determinant of resistance has provided opportunities for monitoring such resistance on a global scale., Methods: We analyzed the K13-propeller sequence polymorphism in 14,037 samples collected in 59 countries in which malaria is endemic. Most of the samples (84.5%) were obtained from patients who were treated at sentinel sites used for nationwide surveillance of antimalarial resistance. We evaluated the emergence and dissemination of mutations by haplotyping neighboring loci., Results: We identified 108 nonsynonymous K13 mutations, which showed marked geographic disparity in their frequency and distribution. In Asia, 36.5% of the K13 mutations were distributed within two areas--one in Cambodia, Vietnam, and Laos and the other in western Thailand, Myanmar, and China--with no overlap. In Africa, we observed a broad array of rare nonsynonymous mutations that were not associated with delayed parasite clearance. The gene-edited Dd2 transgenic line with the A578S mutation, which expresses the most frequently observed African allele, was found to be susceptible to artemisinin in vitro on a ring-stage survival assay., Conclusions: No evidence of artemisinin resistance was found outside Southeast Asia and China, where resistance-associated K13 mutations were confined. The common African A578S allele was not associated with clinical or in vitro resistance to artemisinin, and many African mutations appear to be neutral. (Funded by Institut Pasteur Paris and others.).

Background: Significant progress has been made in reducing the malaria burden in the Asia Pacific region, which is aggressively pursuing a 2030 regional elimination goal. Moving from malaria control to elimination requires National Malaria Control Programmes (NMCPs) to target interventions at populations at higher risk, who are often not reached by health services, highly mobile and difficult to test, treat, and track with routine measures, and if undiagnosed, can maintain parasite reservoirs and contribute to ongoing transmission., Methods: A qualitative, free-text questionnaire was developed and disseminated among 17 of the 18 partner countries of the Asia Pacific Malaria Elimination Network (APMEN)., Results: All 14 countries that responded to the survey identified key populations at higher risk of malaria in their respective countries. Thirteen countries engage in the dissemination of malaria-related Information, Education, and Communication (IEC) materials. Eight countries engage in diagnostic screening, including of mobile and migrant workers, military staff, and/or overseas workers. Ten countries reported distributing or recommending the use of long-lasting insecticide-treated nets (LLINs) among populations at higher risk with fewer countries engaging in other prevention measures such as indoor residual spraying (IRS) (two countries), spatial repellents (four countries), chemoprophylaxis (five countries), and mass drug administration (MDA) (three countries). Though not specifically tailored to populations at higher risk, 11 countries reported using mass blood surveys as a surveillance tool and ten countries map case data. Most NMCPs lack a monitoring and evaluation structure., Conclusion: Countries in the Asia Pacific have identified populations at higher risk and targeted interventions to these groups but there is limited information on the effectiveness of these interventions. Platforms like APMEN offer the opportunity for the sharing of protocols and lessons learned related to finding, targeting and successfully clearing malaria from populations at higher risk. The sharing of programme data across borders may further strengthen national and regional efforts to eliminate malaria. This exchange of real-life experience is invaluable to NMCPs when scarce scientific evidence on the topic exists to aid decision-making and can further support NMCPs to develop strategies that will deliver a malaria-free Asia Pacific by 2030.

Background: Over the last decade, the incidence of confirmed malaria has declined significantly in Nepal. The aim of this paper is to assess the spatio-temporal distribution of malaria and its association with climatic factors and vector control interventions in two high-risk districts of Nepal., Methods: Hotspot analysis was used to visualize the spatio-temporal variation of malaria incidence over the years at village level and generalized additive mixed models were fitted to assess the association of malaria incidence with climatic variables and vector control interventions., Results: Opposing trends of malaria incidence were observed in two high-risk malaria districts of eastern and far-western Nepal after the introduction of long-lasting insecticidal nets (LLINs). The confirmed malaria incidence was reduced from 2.24 per 10,000 in 2007 to 0.31 per 10,000 population in 2011 in Morang district but increased from 3.38 to 8.29 per 10,000 population in Kailali district. Malaria hotspots persisted mostly in the same villages of Kailali district, whereas in Morang district malaria hotspots shifted to new villages after the introduction of LLINs. A 1° C increase in minimum and mean temperatures increased malaria incidence by 27% (RR =1.27, 95% CI =1.12-1.45) and 25% (RR =1.25, 95% CI =1.11-1.43), respectively. The reduction in malaria incidence was 25% per one unit increase of LLINs (RR =0.75, 95% CI =0.62-0.92). The incidence of malaria was 82% lower in Morang than in Kailali district (RR =0.18, 95% CI =0.11-0.33)., Conclusions: The study findings suggest that LLIN coverage should be scaled up to entire districts rather than high-incidence foci only. Climatic factors should be considered for malaria micro-stratification, mosquito repellents should be prescribed for those living in forests, forest fringe and foothills and have regular visits to forests, and imported cases should be controlled by establishing fever check posts at border crossings.

Background: Moving from malaria control to elimination requires national malaria control programmes to implement strategies to detect both symptomatic and asymptomatic cases in the community. In order to do this, malaria elimination programmes follow up malaria cases reported by health facilities to carry out case investigations that will determine the origin of the infection, whether it has been imported or is due to local malaria transmission. If necessary, the malaria programme will also carry out active surveillance to find additional malaria cases in the locality to prevent further transmission. To understand current practices and share information on malaria elimination strategies, a survey specifically addressing country policies on case investigation and reactive case detection was carried out among fourteen countries of the Asia Pacific Malaria Elimination Network (APMEN)., Methods: A questionnaire was distributed to the malaria control programme managers amongst 14 countries in the Asia Pacific who have national or sub-national malaria elimination goals., Results: Results indicate that there are a wide variety of case investigation and active case detection activities employed by the 13 countries that responded to the survey. All respondents report conducting case investigation as part of surveillance activities. More than half of these countries conduct investigations for each case. Over half aim to accomplish the investigation within one to two days of a case report. Programmes collect a broad array of demographic data during investigation procedures and definitions for imported cases are varied across respondents. Some countries report intra-national (from a different province or district) importation while others report only international importation (from a different country). Reactive case detection in respondent countries is defined as screening households within a pre-determined radius in order to identify other locally acquired infections, whether symptomatic or asymptomatic. Respondents report that reactive case detection can be triggered in different ways, in some cases with only a single case report and in others if a defined threshold of multiple cases occurs. The spatial range of screening conducted varies from a certain number of households to an entire administrative unit (e g, village). Some countries target symptomatic people whereas others target all people in order to detect asymptomatic infections. The majority of respondent programmes collect a range of information from those screened for malaria, similar to the range of information collected during case investigation., Conclusion: Case investigation and reactive case detection are implemented in the malaria elimination programmes in the Asia Pacific, however practices vary widely from country to country. There is little evidence available to support countries in deciding which methods to maintain, change or adopt for improved effectiveness and efficiency. The development and use of common evaluation metrics for these activities will allow malaria programmes to assess performance and results of resource-intensive surveillance measures and may benefit other countries that are considering implementing these activities.

The study has demonstrated the evidence of leptospirosis infection in the country. It has also highlighted the challenges and the need of further researches on this disease, which seems to be under reported in the country.

Because available data suggest that resistance of Plasmodium falciparum to sulfadoxine-pyrimethamine (SP) is increasing in Nepal, an open-label, parallel-group efficacy/safety study was conducted in 99 Nepalese patients with uncomplicated falciparum malaria randomized 2:1 to artemetherlumefantrine (AL) or SP. Efficacy was assessed from clinical and microscopic evidence of treatment failure. Four SP-treated patients (12.1%; 95% CI, 4.0-29.1%) redeveloped parasitemia during the 28-day follow-up versus 0% (95% CI, 0-6.9%) in the AL group (P = 0.011), a difference that was confirmed by polymerase chain reaction (PCR) analysis of parasite DNA. PCR detected an additional six patients (two SP and four AL) with sub-microscopic gametocytemia or breakthrough parasitemia between Days 14 and 28, suggesting that AL efficacy was lower than estimated by microscopy. Dhfr and dhps mutations were not associated with outcome. AL is more effective than SP for uncomplicated malaria in Nepal, but regular monitoring of its efficacy should be carried out if this combination therapy is introduced.

BACKGROUND: Human infection with Wuchereria bancrofti causes a disabling parasitic disease known as lymphatic filariasis, which is a major public health and socio-economic problem in many parts of the world. At the onset of the study, little was known of the distribution of filariasis and its current importance as a public health problem in Nepal. METHODS: Epidemiological mapping was undertaken to determine the prevalence of infection by Wuchereria bancrofti in 37 districts of Nepal between July to December 2001. The study population above 15 years of age was selected, and the immunochromatographic test (ICT Filariasis) was used to screen for circulating filarial antigen (CFA). RESULTS: The overall prevalence of lymphatic filariasis from a 4,488-sample population was 13% and 33/37 districts were found to be endemic. On the basis of geographical data, the highest number of cases was found at altitudes between 500-700 m; however, a substantial number of infected individuals were found in the highly populated Kathmandu valley, at altitudes between 900-1,500 metres where transmission appears to take place. Prevalence rates above 20% were found in 11 districts (with the highest rate of 40%), 6-19% were found in 15 districts, and 0.1-5% were in 7 districts.Information on people's knowledge, attitudes and behaviour towards filariasis was also collected by means of a structured questionnaire, which is presented and discussed in the study. CONCLUSIONS: This is the most extensive study of lymphatic filariasis undertaken to date in Nepal. The study indicates that the prevalence of infection is far greater that was previously reported and that lymphatic filariasis should be a much higher health priority than currently given.

Since 1980, visceral leishmaniasis (VL) has reemerged as a public health problem in lowland Nepal. We conducted a case-control study to identify risk factors. In univariate analyses among 84 cases and 105 controls, protective factors included sleeping on a bed or cot (Odds ratio [OR] 0.44, P < 0.01) and sleeping under a bed-net regularly (OR 0.23, P < 0.001) or in the warm months (OR 0.20, P < 0.001). The bed-nets in use in this region were commercially available and untreated with insecticide. Ownership of a cow or buffalo was protective (OR 0.34, P < 0.001), whereas dampness observed in the mud floor of the house was a strong risk factor (OR 4.0, P < 0.001). In multivariable models, bed-net usage, cow or buffalo ownership, and damp floors were significantly associated with altered risk. A program to increase bed-net usage could therefore decrease the incidence of VL in Nepal.

We evaluated the field use of two serologic tests for visceral leishmaniasis (VL), the direct agglutination test (DAT) and rK39 dipstick test, in the context of a case-control study. Most VL cases in Nepal are currently diagnosed on clinical grounds and with relatively non-specific tests such as the formol-gel test. Among 14 newly diagnosed VL patients with bone-marrow slides confirmed positive in two independent laboratories, the sensitivity of both tests was 100%. Among 113 controls with no personal or household history of VL, the specificity of the rK39 was 100% while that of the DAT was 93%. The rK39 was less expensive than DAT, and has the advantages of ease of use and obtaining results within minutes. The wider use of the rK39 dipstick test could improve the specificity of VL diagnosis in Nepal.