Molecular characterization of Heterodoxus spiniger collected from dogs on St. Kitts in the Caribbean.

Heterodoxus spiniger is a louse commonly found on dogs in tropical and subtropical regions including Africa, America and Asia. However, its distribution on the Caribbean islands and DNA sequence are scarce. In the current study, H. spiniger was collected from two client-owned dogs on St. Kitts in the Caribbean. Total DNAs were individually extracted from male and female adult lice from each dog. Duplex PCR was performed to simultaneously amplify 18S rRNA and mitochondrial cox1 from total DNAs followed by simplex PCR for individual targets using duplex PCR products as templates. PCR amplicons were directly sequenced in both directions. 18S rRNA (2073 bp) and cox1 (1539 bp) were 99.71 % and 99.03 % identical among the six new DNA sequences, respectively. These were the largest datasets for H. spiniger deposited into GenBank so far. Phylogenetic analyses showed that all six 18S rRNA sequences formed a clade along with an additional entry of H. spiniger whereas the three sequences of Trinoton spp. formed a separated clade. Similarly, all six cox1 sequences formed a clade along with additional two, one each from India and Japan. Unexpectedly, the Thai isolate was in a separated clade along with the outgroup of Trinoton querquedulae. These data should be invaluable for studying evolution and epidemiological consequences of this important ectoparasite of domestic dogs.