Hematological disorders detected in dogs infected by Hepatozoon canis in a municipality in Mato Grosso do Sul State, Brazil

ABSTRACT A retrospective review of hematological reports of nine dogs detected with Hepatozoon canis infection by microscopic examination of blood smears in a laboratory in the municipality of Dourados, Mato Grosso do Sul, Brazil was conducted. This study aimed to evaluate the hematological profile of these infected dogs, in addition to the occurrence of coinfections with other agents that infect blood cells, since studies concerning canine hepatozoonosis in Brazil are scarce and there are some divergences regarding H. canis infection that still require a resolution. The nine cases of H. canis infection were identified among all dogs examined at the studied laboratory in 2009 and 2010, with an occurrence of 7/1,192 (0.59%; 95% CI 0.15 - 1.02%) positive dogs in the first year and 2/1,313 (0.15%; 95% CI 0.02 - 0.55%) cases in 2010. The analysis of the hematological reports showed an occurrence of coinfection between H. canis and other agents in two (2/9; 22.22%; 95% CI 2.81 - 60.00%) dogs, one with E. canis and another with Babesia spp. (1/9; 11.11%; 95% CI 0.28 - 48.24%). Only the blood test of one dog had no alterations, based on reference values. Anemia was the most frequent hematological alteration (6/9; 66.67%; 95% CI 29.93 - 92.51%). Although the occurrence of H. canis infection was low, significative hematological alterations were observed in most infected dogs. Coinfection with Babesia spp. and E. canis was detected in two dogs and the hematological alterations cannot be attributed exclusively to H. canis in these animals. Longitudinal studies would be of fundamental importance to determine the causality of these alterations. These results highlight the importance of differential diagnosis in dogs when there is clinical suspicion of infection by hemoparasites, since the hematological changes in dogs infected by H. canis are quite variable.