Epidemiology of American tegumentary leishmaniasis in domestic dogs in an endemic zone of western Venezuela.

Domestic dogs are not only reservoir hosts of the American zoonotic visceral leishmaniasis (ZVL) but of the American zoonotic tegumentary leishmaniasis (ATL) as well, for different reasons. However it is still controversial to state that dogs are incriminated as ATL reservoir hosts as there is evidence that humans and dogs are likely to be exposed in the same way to sandfly vector. In Venezuela this issue has not been completely addressed, for this reason we selected a location inside Trujillo city to study eco-epidemiological conditions as well as to survey a significant sample of dogs by Montenegro Skin Test (MST). Antigen was prepared according to standard procedure using Leishmania (V) braziliensis promastigotes (80 microg/ml); response was read 48 hours post-inoculation with an induration size > 5 mm being considered as positive. The study place is an endemic mountainous semi-urban area located at 850-950 masl with an average rainfall of 150 mm/year. We evaluated 61 dogs in 46 houses with 168 human beings. Among the human population 27 cases of ATL were reported (16.1%). With the MST we found 19 positive-reaction dogs (31%) (mean MST size of 9.58 mm, 95% CI: 8.41-10.75) in 13 houses (28%). Multivariate analysis did not reveal significant association between domestic MST positive-dog ownership and human ATL cases (RR = 1.48, p = 0.28). Although some studies have indicated that dog ownership and dog infection rates are associated with an increased risk of human disease in different evaluated places, this question has not been completely answered in Venezuelan studied zones, further research is necessary.