Molecular Screening and Genetic Identification of Anaplasma platys in Brown Dog Tick (Rhipicephalus sanguineus s. l.) Infested on Stray Dogs in Taiwan

Abstract

Anaplasma platys is a tick-borne zoonotic pathogen of canines. In this study, the presence of A. platys was screened for in brown dog ticks (Rhipicephalus sanguineus s. l.) infesting stray dogs in Taiwan to determine overall prevalence. This study represents the first instance of genetic identification of A. platys in brown dog ticks in Taiwan. In total, we examined 324 brown dog ticks for A. platys infection by nested polymerase chain reaction assay targeting the 16S ribosomal RNA gene. The general prevalence of A. platys infection was 3.1%, with 3.6%, 4.0%, and 2.1% in nymph, female, and male ticks, respectively. Monthly prevalence of infection was observed from May to September. Genetic relatedness was determined by comparing the sequences of the 16S rRNA gene obtained from six Taiwan strains and seventeen other strains, representing six genospecies of Anaplasma spp. and three outgroups (Ehrlichia canis, Rickettsia rickettsia, and Escherichia coli). All Taiwan specimens were shown to genetically belong to the A. platys group, and could be clearly discriminated from other Anaplasma spp. Genetic similarities revealed a 100% identity match with various A. platys documented in GenBank. This study highlights the epidemiological importance of geographical transmission of A. platys among dogs and the possible risk for human infections in Taiwan.