Molecular Genetics of Hepatozoon canis With a Note on Effect of Parasite on the Complete Blood Count Profile of Canine Hosts

ABSTRACT

Hepatozoon canis is the causative agent of canine hepatozoonosis that results in lethargy and severe anemia during acute infection in dogs. In this investigation, 654 blood samples were collected from apparently healthy dogs in Punjab and Khyber Pakhtunkhwa (KPK) provinces in Pakistan and screened for the presence of H. canis . Phylogenetic diversity of the detected H. canis DNA, infection‐associated risk factors and parasite‐induced alterations in the host's complete blood count were also evaluated. PCR‐based screening confirmed the H. canis infection in 48 out of 654 (7.3%) dog blood samples. The presence of this apicomplexan protozoa was confirmed through Sanger sequencing. Phylogenetic reconstruction using the H. canis 18S rRNA gene showed that the sequences generated in this study clustered closely with isolates previously reported from India, Australia, Iran, Zambia, China, Spain, and Brazil. The risk factor assessment indicated that parasite prevalence differed significantly between the sampling sites but did not vary between the dog breeds, animal sex, and the presence or lack of ecto‐parasitic infestation in dogs. Reduced hematocrit levels were recorded in H. canis infected dogs. In conclusion, H. canis was prevalent among the dogs in surveyed regions of Pakistan, with infection rates varying significantly among sampling districts. Furthermore, infected dogs exhibited reduced hematocrit levels, suggesting that H. canis infection may contribute to hematological alterations even in apparently healthy animals.