Serological evidence of Histoplasma capsulatum infection among dogs with leishmaniasis in Brazil.

Histoplasmosis is a systemic infection caused by the fungus Histoplasma capsulatum. Environmental sources of infection for humans and animals in certain regions and the prevalence of infection in animals are frequently unknown. Because of the clinical and epidemiological similarities between histoplasmosis and leishmaniasis in northeastern Brazil, we decided to investigate the serologic evidence of H. capsulatum in dogs, considering that these animals can act as sentinels for histoplasmosis. A total of 224 serum samples from dogs were tested for antibodies against H. capsulatum through immunodiffusion. A total of 128 (57.14%) samples were positive for leishmaniasis by indirect immunofluorescence assay and four (1.78%) samples were positive for antibodies against H. capsulatum. Immunological evidence of the co-existence of histoplasmosis and leishmaniasis in dogs living in urban areas was observed. Diagnosis and clinical management of these diseases in endemic areas should be improved by veterinarians.