Infectividade para a Lutzomyia longipalpis em cães com sorologia positiva para a Leishmania (Leishmania chagasi)

Abstract

Visceral Leishmaniasis (VL) in Brazil is an infection caused by the protozoan parasite Leishmanía (Leíshmania) chagasí. The domestic dog is considered the most important reservoir of the parasite. The main strategy for the control seeks to identify the positive dogs through serological screenings, and subsequent elimination of these. However this current politics adopted as prevention measure and control of VL comes being questioned by not showing satisfactory confirmation in the reduction of the prevalence of VL in the human population. This study had the objective of evaluating the reservoir potential of the dog besides to identify the possible more frequent clinical signs associated to the infectiousness and seropositiveness. Dogs with positive (n=38) and negative (n=11) for the serological ELISA test were studied through xenodiagnosis experiments to determine the infectiousness to phlebotomine vector Lutzomyia longipalpis. Infectiousness for Lu. longipalpis was observed in 36,84% (14) of the dogs from seropositive group. None of the seronegative dogs presented infectiousness to the sand flies. This difference was statisticaly significant. The clinical signs loss of weight and big fingernails showed to be associated with seropositiveness and infectiousness. Besides, dogs that exhibited these conditions infected a significantly larger number of sand flies. On the other hand, was not observed association among the clinical signs of alopecia, utceration and apathy. Younger dogs (<3 anos) infected sand flies with a higher frequency. With relationship to the breed of the animals, the cross-bred dogs race was the most frequent among the seropositives. These results confirm the importance of the dog in the epidemiology of VL as infection source for the sand fly and they indicate that the clinical signs loss of weight, big fingernails and age are a strong indicative of the dogs infectiousness potential