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

Lina Ghassan Younis, Axel Kroeger, Anand B. Joshi, Murari Lal Das, Mazin Omer, Vivek Kumar Singh, Chitra Kumar Gurung, Megha Raj Banjara

Author summary

Visceral leishmaniasis (VL) is a fatal disease if not treated in time. It is the disease of the poorest people. Poor housing and sanitation around the house are considered as the risk factors for the occurrence of VL. The main objective of our research was to explore multiple risk factors from different housing and land lot- typologies for VL occurrence and transmission through a case-control study. Some of our results reveal that inside the dwelling the likelihood of having clinical VL was substantially enhanced by providing suitable breeding sites for the insect vectors; as an example: the probability of getting VL disease was about ten times higher when there were sacks (empty or filled) near sleeping areas. Also cracks in walls and floors were found to contribute to vector transmission but also particular wall structures such as bamboo walls, and finishes such as animal manure were shown to be optimal for vector breeding. Furthermore, certain animals and plant types in the immediate environment seem to attract the vectors and to have a substantial effect on VL occurrence. Thus, given the alarming increase of VL in previously nonendemic areas of Nepal, these findings, among others, will allow readers and policymakers to better understand the “hidden” VL transmission factors, and will–hopefully- encourage initiating future studies.