CyClOSPOriaSiS iN NEPal

Abstract. Nepal is one of the most highly endemic areas for cyclosporiasis in the world. Initial studies of the parasitosis in Nepal were among expatriates and tourists in the country. The present report, however, is a review of studies carried out since 1995 on the epidemiology of Cyclospora cayetanensis and infection in the Nepali populations. The parasitosis was found to occur mostly in children 2-11 years of age. Stools from several thousands of patients with diarrhea were examined, and approximately 6-30% were positive for oocysts of the parasite. The majority of patients were seen during the rainy season. Stool specimens from animals were examined, and oocysts were recovered from six chickens, two monkeys, three dogs, and five rats. PCR/RFLP analysis of oocysts from one monkey, one dog, and 2 chickens were positive for Cyclospora sp. Oocysts of Cyclospora were also found in sewage, a pond and two irrigation canals, and the washwater of cabbage, lettuce, mustard leaves, and basil. Basil may be an important source of infection since it is often eaten raw

Mapping of lymphatic filariasis in Nepal

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

Pilot study on wastewater surveillance of dengue virus RNA: Lessons, challenges, and implications for future research

Dengue virus (DENV) is an enveloped, single-stranded RNA virus that causes approximately 390 million infections, leading to 40,000 deaths annually. Due to the increasing trend of urbanization, water supply scarcity, and climate change, dengue is regarded as the “disease of the future,” requiring robust surveillance for the early detection of DENV infection. Since the virus is shed in urine and saliva and persists in wastewater at different temperatures, our study conducted wastewater surveillance as a novel approach to monitor dengue outbreaks in the Kathmandu Valley, Nepal. The viral concentrates (n = 34), which were previously collected and concentrated from municipal and hospital wastewater, and river water using the electronegative membrane-vortex method, were tested for DENV using quantitative reverse transcription polymerase chain reaction (RT-qPCR) and digital PCR (RT-dPCR). Pepper mild mottle virus, a process control and endogenous biomarker, was detected in all the samples with concentrations ranging from 8.0 to 10.0 log10 copies/L, whereas DENV was not detected in any sample using RT-dPCR and RT-qPCR. The undetected DENV in this study could be attributed to the collection of grab wastewater samples during a low relative prevalence of dengue infection in the region, insufficient sample volume processed, probable viral nucleic acid degradation due to storage of viral concentrate at -25 °C for a long period of time, or inefficiency of the primary concentration method used. This study highlights critical gaps in knowledge and provides recommendations for future implementation of wastewater surveillance of dengue outbreaks, especially in regions where dengue was recently introduced, clinical surveillance is limited, and wastewater surveillance for polio has been adopted.Peer reviewe

Delimitation of lymphatic filariasis transmission risk areas: a geo-environmental approach

BACKGROUND: The Global Programme to Eliminate Lymphatic Filariasis (GPELF) depends upon Mass Drug Administration (MDA) to interrupt transmission. Therefore, delimitation of transmission risk areas is an important step, and hence we attempted to define a geo-environmental risk model (GERM) for determining the areas of potential transmission of lymphatic filariasis. METHODS: A range of geo-environmental variables has been selected, and customized on GIS platform to develop GERM for identifying the areas of filariasis transmission in terms of "risk" and "non-risk". The model was validated through a 'ground truth study' following standard procedure using GIS tools for sampling and Immuno-chromotographic Test (ICT) for screening the individuals. RESULTS: A map for filariasis transmission was created and stratified into different spatial entities, "risk' and "non-risk", depending on Filariasis Transmission Risk Index (FTRI). The model estimation corroborated well with the ground (observed) data. CONCLUSION: The geo-environmental risk model developed on GIS platform is useful for spatial delimitation purpose on a macro scale

Detection of Pathogenic Viruses, Pathogen Indicators, and Fecal-Source Markers within Tanker Water and Their Sources in the Kathmandu Valley, Nepal

Tanker water is used extensively for drinking as well as domestic purposes in the Kathmandu Valley of Nepal. This study aimed to investigate water quality in terms of microbial contamination and determine sources of fecal pollution within these waters. Thirty-one samples from 17 tanker filling stations (TFSs) and 30 water tanker (WT) samples were collected during the dry and wet seasons of 2016. Escherichia coli was detected in 52% of the 31 TFS samples and even more frequently in WT samples. Of the six pathogenic viruses tested, enteroviruses, noroviruses of genogroup II (NoVs-GII), human adenoviruses (HAdVs), and group A rotaviruses were detected using quantitative PCR (qPCR) at 10, five, four, and two TFSs, respectively, whereas Aichi virus 1 and NoVs-GI were not detected at any sites. Index viruses, such as pepper mild mottle virus and tobacco mosaic virus, were detected using qPCR in 77% and 95% out of 22 samples, respectively, all of which were positive for at least one of the tested pathogenic viruses. At least one of the four human-associated markers tested (i.e., BacHum, HAdVs, and JC and BK polyomaviruses) was detected using qPCR in 39% of TFS samples. Ruminant-associated markers were detected at three stations, and pig- and chicken-associated markers were found at one station each of the suburbs. These findings indicate that water supplied by TFSs is generally of poor quality and should be improved, and proper management of WTs should be implemented

Presence of Human Enteric Viruses, Protozoa, and Indicators of Pathogens in the Bagmati River, Nepal

Quantification of waterborne pathogens in water sources is essential for alerting the community about health hazards. This study determined the presence of human enteric viruses and protozoa in the Bagmati River, Nepal, and detected fecal indicator bacteria (total coliforms, Escherichia coli, and Enterococcus spp.), human-fecal markers (human Bacteroidales and JC and BK polyomaviruses), and index viruses (tobacco mosaic virus and pepper mild mottle virus). During a one-year period between October 2015 and September 2016, a total of 18 surface water samples were collected periodically from three sites along the river. Using quantitative polymerase chain reaction, all eight types of human enteric viruses tested—including adenoviruses, noroviruses, and enteroviruses, were detected frequently at the midstream and downstream sites, with concentrations of 4.4–8.3 log copies/L. Enteroviruses and saliviruses were the most frequently detected enteric viruses, which were present in 72% (13/18) of the tested samples. Giardia spp. were detected by fluorescence microscopy in 78% (14/18) of the samples, with a lower detection ratio at the upstream site. Cryptosporidium spp. were detected only at the midstream and downstream sites, with a positive ratio of 39% (7/18). The high concentrations of enteric viruses suggest that the midstream and downstream regions are heavily contaminated with human feces and that there are alarming possibilities of waterborne diseases. The concentrations of enteric viruses were significantly higher in the dry season than the wet season (p < 0.05). There was a significant positive correlation between the concentrations of human enteric viruses and the tested indicators for the presence of pathogens (IPP) (p < 0.05), suggesting that these IPP can be used to estimate the presence of enteric viruses in the Bagmati River water

Occurrence and Reduction of Shiga Toxin-Producing Escherichia coli in Wastewaters in the Kathmandu Valley, Nepal

Inadequately treated effluents discharged from wastewater treatment plants (WWTPs) severely affect the environment and the surrounding population. This study analyzed the presence of the Shiga toxin-producing Escherichia coli (STEC) genes, stx1, and stx2, and the E. coli gene, sfmD, in municipal WWTP A (n = 11) and B (n = 11) where the reductions were also evaluated; hospitals (n = 17), sewage treatment plants (STPs) (n = 4) and non-functional WWTPs (not-working WWTPs) (n = 5) in the Kathmandu Valley, Nepal. The sfmD gene was detected in 100% of the samples in WWTPs, hospitals, and not-working WWTPs and 50% of STP samples. The highest detection of stx1 and stx2 was shown in the WWTP influents, followed by WWTP effluents, not-working WWTP wastewater, hospital wastewater, and STP wastewater. Log10 reduction values of sfmD, stx1, and stx2 in WWTP A were 1.7 log10, 1.7 log10, 1.4 log10, whereas those in WWTP B were 0.5 log10, 0.6 log10, 0.5 log10, respectively, suggesting the ineffective treatment of STEC in the wastewater in the Kathmandu Valley. The high concentrations of the stx genes in the wastewaters suggest the increasing presence of aggressive STEC in the Kathmandu Valley, which should be a major public health concern

Zinc modifies the association between nasopharyngeal Streptococcus pneumoniae carriage and risk of acute lower respiratory infection among young children in rural Nepal

Nasopharyngeal (NP) carriage is necessary for Streptococcus pneumoniae (Spn) transmission and invasive infection. This study evaluated the effect of zinc prophylaxis on the association between NP colonization with Spn and acute lower respiratory infection (ALRI) in children aged 1-35 mo living in a rural district in southern Nepal. We compared carriage prevalence of Spn in 550 ALRI cases with that of healthy age- and season-matched controls. This study, conducted from December 2003 to July 2005, was nested in a community-randomized trial designed to evaluate the effect of zinc on morbidity and mortality in 1- to 36-mo-old children. They were randomized to receive either 10-mg tablets of zinc or placebo daily until discharge. Approximately 75% of cases and controls were Spn carriers. There was an interaction between zinc and Spn carriage (P = 0.091). Spn carriage increased the risk of ALRI in the placebo group [adjusted matched odds ratio (AMOR) = 2.57; P = 0.025] but not in the zinc group (AMOR = 0.95; P = 0.890). Among the subset of symptomatic cases and their controls, the odds of ALRI for Spn carriers in the placebo group was 30 times greater (AMOR = 78.09; P = 0.006) than in the zinc group (AMOR = 2.77; P = 0.288). These findings suggest that zinc prophylaxis may protect children against ALRI associated with carriage of Spn and that the effect may differ by infectious etiology. © 2008 American Society for Nutrition