Origin, distribution, and a metagenomic pathobiome analysis of the invasive Haemaphysalis punctata tick in the eastern United States

The red sheep tick, Haemaphysalis punctata, was recently discovered for the first time in the western hemisphere and in the US on Block Island, Rhode Island. Ticks were collected from the environment and found in archived collections from 2010-2021. The invasion of this tick species presents a potential threat to livestock, wildlife, and human health as the host associations and vector potential of this invasive pest in the US are unknown. In its native range, H. punctata feeds on avian, small mammal, ungulate, and human hosts and are known to vector several pathogens (Babesia spp., Brucella spp., Rickettsia spp., Theileria spp., Tick-borne encephalitis, etc.). To determine the potential country of origin of H. punctata, a phylogenetic analysis of the cox1 gene compared sequences from the Block Island population to several countries from their native range in the Palearctic region. While H. punctata has established itself on Block Island and different life stages were recovered, the population has remained low throughout the study period. No ticks were recovered from small mammals, but larvae were collected from native avian species, suggesting H. punctata may have arrived in the US on migratory birds from Europe. To determine if the US population is harboring pathogens of human concern, the pathobiome using two high throughput sequencing approaches, virus enrichment and shotgun metagenomics, was examined on Block Island archived samples (n=15). These results provide evidence on the country H. punctata invaded from, population abundance and distribution, and the potential threat to human health in the US.