First Molecular Survey and Phylogenetic Identification of a Zoonotic Pathogen, Anaplasma platys, in Hard Ticks Infesting Dogs in Southern Taiwan

Anaplasma platys was recognized as a zoonotic pathogen for canine and human infections. However, there is no confirmed evidence demonstrating the existence of A. platys within hard ticks (Rhipicephalus sanguineus sensu lato) infesting dogs in Southern Taiwan. We conducted a field survey for the detection of Anaplasma infection by screening the R. sanguineus s. l. ticks collected from dogs. Molecular detection was performed via a nested-PCR assay targeting the 16S rRNA gene of Anaplasma. Phylogenetic analyses were performed via neighbor-joining against maximum parsimony methods. The genetic relatedness was analyzed via pairwise distance calculation, using the Kimura 2-parameter model. The A. platys infection was detected in various life stages of R. sanguineus s. l. ticks, with an infection rate of 0.8%, 1.0% and 1.4% in nymphs, males and females, respectively. Monthly prevalence was observed from July to October. The genetic identity of detected Anaplasma strains from Taiwan was phylogenetically affiliated to the A. platys species with a 100% sequence homology verified from different countries. This study reveals the first molecular evidence of a zoonotic pathogen, A. platys, detected in R. sanguineus s. l. ticks from Southern Taiwan. Further investigation focused on the vectorial capacity of R. sanguineus s. l. ticks for transmitting A. platys will be beneficial to reveal the public health importance regarding the potential risk for canine and human infection in Southern Taiwan.