A cross-sectional study of Leishmania spp. infection in clinically healthy dogs with polymerase chain reaction and serology in Greece.

A total of 73 clinically healthy hunting dogs, experiencing an outdoor lifestyle and originating from an area where canine leishmaniasis is endemic, were included in the study. Polymerase chain reaction (PCR) and indirect immunofluorescent antibody test (IFAT) for Leishmania spp. were done on bone marrow and serum samples, respectively, obtained from all 73 dogs, just before the beginning of the sandfly season. PCR was found positive in 46/73 (63%) whereas, IFAT only in 9/73 (12.3%) of the dogs. The prevalence and the incidence of Leishmania infection by PCR were 61.9 and 47.1%, respectively. No association was found between the breed, age, sex, length of hair coat of the dog, urban or rural life and the presence of ample vegetation and water collections in the proximity of their living quarters, and the result of PCR. These findings clearly demonstrate that most of the dogs residing areas where leishmaniasis is endemic become infected but usually remain seronegative. Serological screening of the general canine population in these areas may result in an underestimation of the true prevalence of the infection rate.