Genotypic Analysis of Piroplasms and Associated Pathogens from Ticks Infesting Cattle in Korea

Tick-borne pathogens (TBPs) impose an important limitation to livestock production worldwide, especially in subtropical and tropical areas. Earlier studies in Korea have examined TBPs residing in ticks and animals; however, information on multiple TBPs in ticks infesting cattle is lacking. This study assessed the prevalence of TBPs in ticks parasitizing cattle. A total of 576 ticks, including 340 adults and 236 nymphs, were collected from cattle in Korea between 2014 and 2018. All ticks collected were identified as Haemaphysalis longicornis based on their morphological and molecular characteristics. Among piroplasms and other tick-associated pathogens, seven TBP genes, namely Theileria orientalis (5.0%), Anaplasma bovis (2.3%), Anaplasma capra (4.7%), Anaplasma phagocytophilum-like Anaplasma spp. (APL) clades A (1.9%) and B (0.5%), Ehrlichia canis (1.6%), and Candidatus Rickettsia longicornii (17.5%), were detected. Bartonella spp. and severe fever with thrombocytopenia syndrome virus were not found. To our knowledge, this is the first study to report the presence of the pathogens T. orientalis major piroplasm surface protein genotypes 3 and 7, A. capra, and APL in ticks from Korea. Cattle ticks may be maintenance hosts for many TBPs, and veterinary and medical clinicians should be aware of their high probability of infection and clinical complexity in humans.