Rabies virus strains circulating in Bhutan: implications for control.

We report a molecular epidemiological study of rabies virus strains circulating in animal populations in Bhutan, and investigate potential origins of these viruses. Twenty-three rabies virus isolates originating from dogs and other domestic animals were characterized by sequencing the partial nucleoprotein (N) gene (395 bp). Phylogenetic analysis was conducted and the Bhutanese isolates were compared with rabies viruses originating from other parts of the world. Phylogenetic analysis showed that Bhutanese isolates were highly similar and were closely related to Indian strains and South Asian Arctic–like–1 viruses. Our study suggests that the rabies viruses spreading in southern parts of Bhutan have originated from a common ancestor, perhaps from the Indian virus strain. Keywords: molecular epidemiology, rabies, Arctic–like virus, BhutanThailand Research Fund (grant No.DBG5180026

Rabies virus strains circulating in Bhutan: implications for control.

postprintWe report a molecular epidemiological study of rabies virus strains circulating in animal populations in Bhutan, and investigate potential origins of these viruses. Twenty-three rabies virus isolates originating from dogs and other domestic animals were characterized by sequencing the partial nucleoprotein (N) gene (395 bp). Phylogenetic analysis was conducted and the Bhutanese isolates were compared with rabies viruses originating from other parts of the world. Phylogenetic analysis showed that Bhutanese isolates were highly similar and were closely related to Indian strains and South Asian Arctic–like–1 viruses. Our study suggests that the rabies viruses spreading in southern parts of Bhutan have originated from a common ancestor, perhaps from the Indian virus strain. Keywords: molecular epidemiology, rabies, Arctic–like virus, BhutanThailand Research Fund (grant No.DBG5180026

Size and demography pattern of the domestic dog population in Bhutan: Implications for dog population management and disease control

Understanding the demography of domestic dogs is essential to plan the dog population management and rabies control program. In this study, we estimated the owned and stray dog population and the proportion of owned dogs that are free-roaming in Bhutan. For this, a cross-sectional household surveys were conducted in six districts (both urban and rural areas) and two border towns in southern Bhutan. The population estimation was done by extrapolation of the mean number of dogs per household and dogs per person, whilst mark-resight survey was conducted to estimate the proportion of owned dogs that were free-roaming. A total of 1,301 (rural:585; urban:716) respondents (one per household) were interviewed of which 173 households (24.4%) in urban areas owned 237 dogs whilst 238 households (40.8%) in rural areas owned 353 dogs. The mean number of dogs per dog owning household was estimated to be 1.44 (urban:1.37 dogs; rural:1.48 dogs) and dogs per household was estimated to be 0.45 (urban:0.33; rural:0.60). The dog: human ratio was 1:16.30 (0.06 dogs per person) in urban areas and 1:8.43 (0.12 dogs per person) in rural areas. The total owned dog population based on the mean number of dogs per household and dogs per person were estimated to be 65,312 and 71,245 in the country, respectively. The male: female ratio of the owned dog was 1.31:1 in urban areas and 2.05:1 in rural areas. Majority of the dogs were local non-descript breeds in both urban (60.8%) and rural (78%) areas, and the most common source was acquisition from friends or family (44.7%). The stray dog population in Bhutan was estimated to be 48,379 (urban:22,772; rural:25,607). Of the total estimated owned dog population in the two border towns, the proportion that were found free-roaming was estimated to be 31%. The different dog population estimation methods were compared and discussed in this paper. This study generated baseline data on the demographic patterns of the owned and stray dogs in Bhutan which will be useful for planning and monitoring dog population management and rabies control program in the country

A cross-sectional survey of population demographics, the prevalence of major disease conditions and reason-specific proportional mortality of domestic cattle in the Kingdom of Bhutan

We describe the population demographics, rudimentary measures of reproductive performance, the prevalence of major disease conditions and reason-specific proportional mortality for cattle owned by villagers in 16 dzongkhags (districts) in Bhutan based on the findings of a cross-sectional study carried out between March 2012 and May 2014. The animal health issues that were of concern for livestock owners are also identified. Study households were selected using a stratified, two-stage cluster design. Districts (dzongkhags) formed the strata. Villages within dzongkhags were the first sampling stage and households within villages the second sampling stage. All cattle within each selected household comprised the study population.Questionnaires were collected from 409 households with 1480 standing cattle. A total of 71.0% (95% CI 67.9%-74.1%) of the standing cattle population were female and the median age of cattle was 5 years (Q25 3 years; Q75 7 years). Exotic breeds of cattle (Jerseys, Brown Swiss, and their crosses) comprised 41.4% of the cattle population with local breeds making up the remainder. Although exotic breeds of cattle had a significantly lower age at first calving (median 4 years) compared to local breeds (median 4.8 years) there was no significant difference in the number of calving events per cow for the two breed groups. Diarrhoea was the most prevalent disease condition with 2.8 (95% CI 1.5-4.6) cases per 100 animals followed by bovine enzootic haematuria with 1.9 (95% CI 1.0-3.3) cases per 100 animals. The most frequently cited cause of death was misadventure (proportional mortality 26.2%, 95% CI 15.7%-39.2%) followed by old age (17.8%, 95% CI 9.5%-29.4%). A lack of access to adequate fodder and pasture was the animal health issue that was cited by interviewees most frequently.We provide no evidence that exotic breeds of cattle have superior reproductive performance compared with local breeds. The major cattle health concern cited by interviewees, lack of access to fodder, is likely to contribute to suboptimal productivity and the relatively high incidence of bovine enzootic haematuria in this population. We propose that a prospective cohort study of Bhutanese cattle is warranted to more fully elucidate factors affecting the productivity and longevity of cattle in Bhutan

Risk factors for foot-and-mouth disease in sedentary livestock herds in selected villages in four regions of Bhutan

AIMS: To identify livestock husbandry practices important for transmission of foot-and-mouth disease (FMD) in the herds and villages of four regions in Bhutan. To consider using this information to enhance the current prevention and control programme, a consideration arising from the failure to control FMD in spite of a control programme in place. METHODS: Between March and May 2009, 383 livestock farmers originating from 80 villages in four districts of Bhutan were interviewed, using a structured questionnaire, about the livestock management practices and incidence of FMD in their herds. Multivariable logistic regression was used to quantify the risk factors that predicted the outcome variable 'farmer-diagnosed FMD in Bhutan'. RESULTS: Sixty-two percent (49/79) of the villages and 87/355 (24%) of herds surveyed had at least one outbreak of FMD within the 5 years preceding the survey. The odds of having FMD in a herd increased substantially (OR=39.2; p0.0001) when cattle mixed with herds from other nearby villages compared with those where mixing did not occur. Those cattle herds mixing with six or more other herds within the same village were 5.3 times (p0.0001) more likely to have had FMD than those mixed with fewer than six herds. Farmers who fed kitchen waste to cattle were 14.1 times (p0.0001), and those who sent their animals for grazing in the forest were 3.1 times (p=0.014), more likely to report FMD in their herds than those who did not. Farmers who kept their cattle always housed in a shed during the day (OR=0.033) or at night (OR=0.29) were less likely to report FMD than those who did not (p0.04). CONCLUSIONS: Mixing of cattle at grazing areas was identified as a risk factor for FMD. This indicates that spread from infected herds and villages, through close contact, could be an important source of disease for non-infected herds in Bhutan. Therefore, quarantining of early cases in affected herds or villages could reduce the spread of disease within and between villages. This study also highlights the potential role of feeding kitchen waste to cattle as a risk factor for FMD. The findings from this study could be considered for strengthening of the FMD control programme in Bhutan

GLOF hazard, exposure, vulnerability, and risk assessment of potentially dangerous glacial lakes in the Bhutan Himalaya

Deglaciation due to atmospheric warming has led to the formation and expansion of numerous glacial lakes, especially in the eastern Himalaya. Many of these glacial lakes are susceptible to glacial lake outburst floods (GLOFs), which can cause far-reaching impacts on downstream infrastructure and livelihoods. This study is a comprehensive assessment of GLOF susceptibility, hazard, exposure, vulnerability, and risk for four potentially dangerous glacial lakes (Bechung Tsho, Raphstreng Tsho, Thorthomi Tsho, and Lugge Tsho) located in the Lunana glacier complex of the Phochu basin in Bhutan. Exposure and risk assessments were based on modelled GLOF hydrodynamics, infrastructure data, population and housing census data. Among the four glacial lakes, Thorthormi Tsho and Lugge Tsho are relatively more susceptible to outburst floods than Raphstreng Tsho and Bechung Tsho. Outflow flood volumes from these lakes range between 6 × 105 and 3 × 108 m3 which can potentially impact over 16,000 people, two hydropower projects, numerous other infrastructures, and agricultural land up to 150 km downstream of the lakes. The GLOF exposed elements are largely in Punakha and Wangdue Phodrang districts, which are located 90 and 100 km downstream of the Lunana glacier complex respectively. Among 17 subdistrict blocks within the basin, one (Lunana) lies in a very high GLOF risk area, while 9 others are in the high GLOF risk zone. The study highlights the importance of multi-source data in improving the knowledge of downstream GLOF risk and serves as a base for improving GLOF risk reduction strategies in high mountain regions

Comparison of mark-resight methods to estimate abundance and rabies vaccination coverage of free-roaming dogs in two urban areas of south Bhutan

In Bhutan, Capture-Neuter-Vaccinate-Release (CNVR) programs have been implemented to manage the dog population and control rabies, but no detailed evaluation has been done to assess their coverage and impact. We compared estimates of the dog population using three analytical methods: Lincoln-Petersen index, the Chapman estimate, and the logit-normal mixed effects model, and a varying number of count periods at different times of the day to recommend a protocol for applying the mark-resight framework to estimate free-roaming dog population abundance. We assessed the coverage of the CNVR program by estimating the proportion of dogs that were ear-notched and visually scored the health and skin condition of free-roaming dogs in Gelephu and Phuentsholing towns in south Bhutan, bordering India, in September-October 2012.The estimated free-roaming dog population in Gelephu using the Lincoln-Petersen index and Chapman estimates ranged from 612 to 672 and 614 to 671, respectively, while the logit-normal mixed effects model estimate based on the combined two count events was 641 (95% CI: 603-682). In Phuentsholing the Lincoln-Petersen index and Chapman estimates ranged from 525 to 583 and 524 to 582, respectively, while the logit-normal mixed effects model estimate based on the combined four count events was 555 (95% CI: 526-587). The total number of dogs counted was significantly associated with the time of day (AM versus PM; P = 0.007), with a 17% improvement in dog sightings during the morning counting events. We recommend to conduct a morning marking followed by one count event the next morning and estimate population size by applying the Lincoln-Peterson corrected Chapman method or conduct two morning count events and apply the logit-normal mixed model to estimate population size.The estimated proportion of vaccinated free-roaming dogs was 56% (95% CI: 52-61%) and 58% (95% CI: 53-62%) in Gelephu and Phuentsholing, respectively. Given coverage in many neighbourhoods was below the recommended threshold of 70%, we recommend conducting an annual "mass dog vaccination only" campaign in southern Bhutan to create an immune buffer in this high rabies-risk area. The male-to-female dog ratio was 1.34:1 in Gelephu and 1.27:1 in Pheuntsholing.Population size estimates using mark-resight surveys has provided useful baseline data for understanding the population dynamics of dogs at the study sites. Mark-resight surveys provide useful information for designing and managing the logistics of dog vaccination or CNVR programs, assessing vaccination coverage, and for evaluating the impact of neutering programs on the size and structure of dog populations over time