Abstract
BACKGROUND: This study investigates the prevalence of leishmaniasis and American trypanosomiasis (Chagas disease) - two neglected vector-borne diseases - in humans and dogs in the Bolivian Chaco region, where high poverty levels increase population vulnerability. Leishmaniasis, which affects millions globally, is widespread in Bolivia, a country reporting some of the highest rates of cutaneous and mucocutaneous cases in Latin America. Chagas disease is endemic across the region, with an estimated 4.5 million individuals affected. METHODS: Blood and serum samples were collected from 189 dogs living in rural communities near the cities of Camiri and Villa Montes. Samples were tested using serological assays and quantitative PCR (qPCR) to detect Leishmania spp. and Trypanosoma cruzi. Additionally, serum samples from 151 school-aged children from both areas were screened for anti-Leishmania antibodies. RESULTS: The seroprevalence of Leishmania in dogs was significantly higher in Villa Montes (46%) compared with Camiri (26%). Moreover, Leishmania DNA was detected by qPCR in 9 out of 125 dogs tested (7.2%). Among children, 13.2% from Villa Montes tested positive for Leishmania antibodies, while no positive cases were found in Camiri. Serological evidence of previous T. cruzi infection was identified in 17.7% of dogs, although all qPCR results for T. cruzi were negative. CONCLUSIONS: These findings highlight the relevance of a One Health approach, as dogs may serve as reservoirs for both parasites, potentially increasing the risk of human transmission. Integrated control measures - including vector management and ongoing surveillance - are essential to reduce transmission and protect public health. Future research should prioritise mapping infection patterns and exploring ecological factors influencing disease dynamics.