Detection of Hepatozoon spp. in dogs in Shiraz, southern Iran and its effects on the hematological alterations

Canine hepatozoonosis is a tick-transmitted apicomplexan infection caused by two species of Hepatozoon, H. canis, and H. americanum. The present research aimed at detection of Hepatozoon spp. in dogs and its effects on hematological alterations. Blood samples were taken from 108 dogs to assess Hepatozoon spp. Phylogenetic analysis was performed based on the 18S rDNA marker by PCR assay and Giemsa-stained blood smear examination. Of the 108 blood samples of dogs tested in the present study, eight (7.40%, 95% CI: 3.25-14.07%) were positive by the Hepatozoon-specific PCR assay. However, in the microscopic examination, only one sample (0.93%) was positive. All of the sequenced samples were H. canis. The Hepatozoon sequences obtained from PCR amplicons in the canine-positive cases exhibited 100% similarity to each other and 98.47-100% similarity to other relevant sequences in GenBank. These findings represent the first molecular evidence of H. canis in dog populations in South Iran. Furthermore, according to the hematological analysis, significantly higher average numbers of neutrophils and lymphocytes were found in the infected group compared to the non-infected dogs. In this study, no statistically significant connection (P<0.05) was observed between H. canis infection and the examined risk factors.