Piroplasm parasites (Apicomplexa: Piroplasmida) in northeastern populations of the invasive Asian longhorned tick, Haemaphysalis longicornis Neumann (Ixodida: Ixodidae), in the United States

Abstract

Piroplasms, which include the agents of cattle fever and human and dog babesiosis, are a diverse group of blood parasites of significant veterinary and medical importance. The invasive Asian longhorned tick, Haemaphysalis longicornis, is a known vector of piroplasms in its native range in east Asia and invasive range in Australasia. In the US state of Virginia, H. longicornis has been associated with Theileria orientalis Ikeda outbreaks that caused cattle mortality. We examined 667 H. longicornis collected in 2021 from three sites in New Brunswick, New Jersey, the US state where established populations of this species were first detected in 2017. We used primers targeting the 18S small subunit rRNA and the cytochrome b oxidase loci and unveiled the presence of DNA from an unidentified Theileria species (in 1 nymph) and Theileria cervi type F (1 adult, 5 nymphs). In addition, we sequenced a 130 bp fragment of the cytochrome oxidase b locus from Odocoileus virginianus, the white-tailed deer, in a partially engorged questing H. longicornis, supporting the association of this tick species with deer. We also detected DNA from an undescribed Babesia sensu stricto ( true Babesia, 2 adults, 2 nymphs) as well as Babesia sp. Coco (1 adult, 1 nymph). Finally, we detected DNA from Babesia microti S837 (1 adult, 4 nymphs). Babesia microti S837 has been sequenced from striped skunks, Mephitis mephitis, and is closely related to the human pathogen B. microti US-type. The five parasites we are associating with H. longicornis represent a diverse assemblage spanning three clades in the piroplasm phylogeny, two undescribed, raising concerns of transmission amplification of veterinary pathogens as well as spillover of pathogens from wildlife to humans.