Molecular Epidemiology, Characterisation of Hepatozoon canis in Dogs as well as in Ticks and Haemato-biochemical Profile of the Infected Dogs in Chennai

Background: Canine hepatozoonosis is caused by Hepatozoon canis and is transmitted through ingestion of an ixodid tick, Rhipicephalus sanguineus sensu lato containing mature oocysts. Periodical screening of vectors and their host for the presence of pathogen acts as reliable method for understanding the pattern of the disease which thereby reduces the chance of disease and the cost of treatment. Methods: A total of 482 blood samples and 47 pooled tick samples collected from 482 dogs during the study period were screened through conventional and molecular techniques for the presence of H. canis. The haematology and biochemical profile of infected animals were evaluated. Positive PCR products were sequenced, compared with the existing sequences and were analysed phylogenetically. Result: Out of 482 blood samples collected from dogs, only 5 were found to be positive microscopically for H. canis while 32 blood samples and 8 tick samples were found positive by polymerase chain reaction (PCR). Amongst epidemiological attributes, age and gender were found to have no significant relationship for the occurrence of the disease while, breed of the dog had a significant association. Haematology and biochemistry revealed profound anaemia, monocytosis and elevated blood urea nitrogen in dogs with H. canis.