Molecular characterization of Hepatozoon spp. in naturally infected dogs in Aydın province

Abstract

Canine hepatozoonosis, a disease caused by the protozoan Hepatozoon canis and Hepatozoon americanum, represents a significant tick-borne disease affecting domestic and wild carnivores. The objective of this study was to detect Hepatozoon species in randomly selected dogs from Aydın by PCR and to elucidate their molecular characterization and phylogenetic differences through sequence analysis. In total, 100 blood samples collected from dogs were analyzed, and the prevalence of Hepatozoon DNA was determined to be 3%, with only three samples testing positive. Partial sequences of the 18S rRNA gene exhibited 100% similarity with corresponding H. canis isolates. Phylogenetic analysis of the 18S rRNA gene region revealed the formation of two primary clusters, one consisting of H. canis isolates and the other comprising different Hepatozoon species. While H. canis isolates formed distinct subclusters, they were all grouped separately from other Hepatozoon species. Furthermore, phylogenetic analysis highlighted the presence of multiple H. canis haplotypes in Türkiye, with intraspecific nucleotide differences ranging from 0.0% to 2.9%. The nucleotide differences among the isolates identified in this study ranged from 0.0% to 1.6%. All sequences obtained in this study have been submitted to GenBank and assigned accession numbers PQ669652, PQ671331 and PQ669658. These findings underscore the need for further investigations into Hepatozoon infections among cats and wild animals in the region. Additionally, the detection of the parasite in vector ticks could offer valuable insights into the genetic diversity and distribution of circulating Hepatozoon species.