Risk factors for visceral leishmaniasis in selected high endemic areas of Morang, Nepal: A case control study

Abstract

Background: Visceral leishmaniasis is a major public health concern in Nepal. During the last few years, several Kala-azar outbreaks have been reported from Terai region including Morang district, Nepal. Objectives: The aim of this study is to determine the risk factors associated with Kala-azar at individual and household levels in selected highly endemic areas of Morang district of eastern Nepal. Methodology: A case control study was conducted in five endemic village development committees of Morang district with 62 cases already treated from B.P. Koirala Institute of Health Sciences and Koshi Zonal Hospital. Two hundred and forty eight controls were selected randomly from the same village at the ratio of 1:4. Data was collected between September and November 2013 using structured questionnaires. Bivariate and multivariate analysis were done and the final model was selected using the backward elimination strategy. Results: This study showed that the majority of cases (29.0%) were from the 13-25 years age group, males are more than females and indigenous caste (74.2%) were affected more than other caste. Living in thatched house (OR 4.57, 95% CI 1.91-10.93), ownership of animal (OR 3.95, 95% CI 1.87-8.37), sleeping on the ground floor (OR 3.90, 95% CI 1.83-8.31),  history of migration to India and proximity to other Kala-azar cases within 50 metres distance of household were significant risk factors for visceral leishmaniasis. The association with socioeconomic status remained significant and there was a clear dose – response effect.  Conclusion: Living in thatched house, ownership of animals, sleeping on the ground floor, history of migration to India, proximity to other Kala-azar cases within 50 metres distance and poverty are the main risk factors associated with visceral leishmaniasis transmission.