Exotic Tick Species Found in Multiple States

Tick season is upon us, so it may come as no surprise that a research group at Oklahoma State University’s (OSU) Center for Veterinary Health Sciences has confirmed the existence of an exotic species of tick in the United States.

Found on a dog in Arkansas, the parasite has been classified as a nymphal longhorned tick or bush tick, Haemaphysalis longicornis, and was discovered through a national tick surveillance project being conducted by the OSU team, led by Susan Little, DVM, PhD, DACVM (parasitology). The lab confirmed the morphologic identification by sequencing and reported the finding to the US Department of Agriculture.

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“We knew to be on the lookout for this tick given recent reports in New Jersey, Virginia, and West Virginia,” said Dr. Little. “We are very glad we were able to assist on efforts to understand the current distribution of this new species.”

H longicornis originated in East Asia and invasive populations have been established in Australia, New Zealand, and several Pacific Islands—and perhaps now, the eastern United States. Earlier this year, the Journal of Medical Entomology published a report of these ticks infesting sheep in Hunterdon County, New Jersey in summer 2017. All life stages were found on the sheep, which had no history of traveling outside of the country. The New Jersey incident was believed to be the first established population of the species ever documented in the United States.

According to a related report in Entomology Today, H longicornis is a unique species of tick because of its capacity for parthenogenesis—reproduction without fertilization, in which females produce offspring that are nearly clones of themselves. It’s this trait that gives the species the ability to infest areas in a short period of time. In fact, among the 27 adults, 41 nymphs, and 1058 larvae collected in New Jersey, just 1 specimen was male.

H longicornis readily feed on cattle, but they are also known to attach to small ruminants, horses, dogs, cats, people, and several common wildlife species as well.

Surveillance is currently ongoing to learn more about where the species is located within the country and if it may be carrying any disease. The Centers for Disease Control and Prevention reports that in China, H longicornis has been suspected to be the vector of severe fever with thrombocytopenia syndrome virus. None of the ticks collected in New Jersey were found to be carrying disease, according to the New Jersey Division of Fish and Wildlife.

In other parts of the world, most modern tick preventives are effective against this species.