A study performed by researchers at ISGlobal, in collaboration with Bolivian researchers, reports the presence of sand flies (the Leishmania vector) inside and near domiciles in urban zones. The results of the study, published in Acta Tropica, could help to explain the increase in the incidence of cutaneous leishmaniasis in the tropic of Cochabamba, where the age range of the affected population has expanded and the number of cases among women has increased over the last decade.
The geographical distribution of leishmaniasis is closely related to the distribution of its vector. In Bolivia, where cutaneous leishmaniasis is the most common form of the disease, there are 86 species of sand flies of which six have been incriminated as vectors of the disease. In the endemic region of Cochabamba, the disease typically affected young males that work in the forest. However, over the last decade, there has been an increase of cases among children under five years and women.
The goal of the study was to obtain data on the sand flies present outside the national park, where previous studies were conducted, and in more urbanized areas of the region. With the help of light traps, the researchers captured sand flies within and near the houses, and identified two of the captured species as incriminated vectors of the disease. The authors suggest that the adaptation of the parasite's transmission cycle to the domestic habitat may provide an explanation for the increasing trend of cutaneous leishmaniasis in the region, including small children and women. Nevertheless, the authors point out that further investigation is needed to confirm intradomiciliary transmission of the disease.
Ballart C, Vidal G, Picado A, Cortez MR, et al. Intradomiciliary and peridomiciliary captures of sand flies (Diptera: Psychodidae) in the leishmaniasis endemic area of Chapare province, tropic of Cochabamba, Bolivia. Acta Trop. 2015 Nov 28;154:121-124.