Molecular Survey of Hepatozoon canis Infection in Domestic Dogs from Sardinia, Italy

SIMPLE SUMMARY: This study was planned to investigate the presence of Hepatozoon species in 51 domestic dogs in Sardinia, Italy. The parasites infecting domestic dogs underwent genetic and phylogenetic analyses. The results of PCR tests based on the 18S rRNA gene illustrated that 13.5% (9/51) of the samples were positive for Hepatozoon spp. DNA. From the obtained positive samples, the nucleotide sequences of the 18S rRNA gene were also determined. In the genetic and phylogenetic analyses, all nucleotide sequences exhibited a close similarity to Hepatozoon canis. The widespread presence of this protozoan species among domestic dogs in Sardinia paves the way for a more accurate description of the epidemiology of these protozoans in the study area. ABSTRACT: Tick-borne protozoans of the genus Hepatozoon have been associated with infections of domestic and wild animals over the world. The occurrence of these apicomplexan agents in Sardinia has been poorly explored so far. In this study, the occurrence of Hepatozoon spp. has been investigated in domestic dogs from nine cities of Sardinia, Italy. Blood samples from each dog were collected and tested molecularly for the presence of Hepatozoon and Babesia/Theileria DNAs. Out of fifty-one dogs, nine were positive for Hepatozoon species based on the molecular detection of the parasite in blood samples. The phylogenetic relationships of strains detected here were also established. The PCR for amplification of the 18S rRNA fragment gene of Babesia/Theileria spp. did not give amplicons in any of the analyzed samples. Our results report the first molecular confirmation of Hepatozoon canis in Sardinian pet dogs and contribute to better understand the presence of these protozoans on the island. This study highlights the importance of recognizing and predicting the risk levels for the canine population, thus increasing the development of specific control measures. Also, since the distribution of hepatozoonosis is closely related to that of the definitive tick host, Rhipicephalus sanguineus, more accurate studies on Rhipicephalus ticks will be needed due to increasing the epidemiological knowledge of Hepatozoon species on the island.