Molecular identification of the Hepatozoan canis in Rhipicephalus sanguineus ticks in Tamil Nadu

Abstract

This study investigated the presence of Hepatozoan canis in ixodid ticks Rhipicephalus sanguineus sensu lato, commonly referred to as the ‘‘kennel tick’’ or ‘‘brown dog tick.’’ Three hundred and twenty four semi engorged ticks were collected from a dog shelter and from naturally infected dogs from Chennai, Madurai and Namakkal districts in Tamil Nadu state, India to identify the Hepatozoan canis infections. The ticks were surface sterilized with ethanol and dissected to separate the midgut and ovary and the DNA was extracted, PCR amplification and sequencing was carried out to obtain a 666 bp fragment of the 3´ half of the 18S rDNA sequences. The nucleotide sequences were compared with respective ones available in GenBank using the National Center for Biotechnology Information (NCBI) Basic Local Alignment Sequence Tool (BLAST) search engine (http://blast.ncbi.nlm.nih.gov/blast.cgi). The nucleotide sequence of 18S rRNA gene of H. canis showed 98.10 percent homology with the sequences of other isolates of H. canis available in the gene bank. Among the 324 ticks examined 15, 25 and 20 per cent H. canis DNA was detected in pooled samples of R. sanguineus ticks collected from Chennai, Madurai and Namakkal respectively.