New Aggressive Tick Species Is Spreading Through the United States

A new tick species that is native to Australia, New Zealand, and eastern Asia, has been springing up in several US states this summer, prompting health officials to warn the general public to take the proper protective measures against potential bites.

The tick (Haemaphysalis longicornis), referred to as the “longhorned tick” or the “bush tick,” was first identified in New Jersey in November 2017 on a sheep in Hunterdon County. Recently, the tick has been detected in Union and Middlesex counties of New Jersey as well, according to the New Jersey Department of Agriculture.

However, New Jersey is not the only state to have identified the tick—it has now been reported in 8 US states.

Virginia was the second state to detect the presence of the tick on an orphaned calf on a beef farm in Albemarle County. The National Veterinary Services Laboratory (NVSL) in Ames, Iowa, confirmed its presence on May 14, 2018. Soon after, on May 21, 2018, NVSL confirmed that the tick was also present in West Virginia after 2 samples were collected from cattle on 2 different premises in Hardy County. The farms from where the samples were collected are located on the border of Virginia, only about 100 miles from Albemarle County.

“This tick has been associated with bacterial and viral tick-borne disease in other parts of the world,” Miguella Mark-Carew, director of epidemiology and prevention services for the West Virginia Department of Health and Human Resources, Bureau for Public Health, stressed in a recent statement. “Like deer ticks that transmit Lyme disease, longhorned ticks are very small and can be difficult to find on people and animals. It is important to conduct full-body tick checks when returning from time outdoors in wooded areas.”

The US Departments of Agriculture (USDA) confirmed the presence of the exotic tick in Arkansas on June 5, 2018, where it was found on a dog in Benton County. The tick was collected and submitted through a research project at Oklahoma State University. The tick was confirmed by the NVSL through a photograph and molecular typing. Later that month, on June 25, the tick was discovered in North Carolina on an opossum in Polk County and confirmed by NVSL.

New York was the next state to report the tick species in several locations throughout Westchester County. In collaboration with investigators from Fordham University and the Lyme Disease Diagnostic Center of New York Medical College, the New York State Department of Health identified the ticks, and the Rutgers University Center for Vector Biology and the USDA confirmed.

Pennsylvania reported the tick in Centre County’s Potter Township on an adult male wild white-tailed deer that had been euthanized on July 10 by the Game Commission as it was exhibiting signs consistent with chronic wasting disease. The Southeastern Cooperative Wildlife Disease Study in Athens, Georgia, collected the ticks from the deer, and NVSL confirmed that they were longhorned ticks.

Most recently, the Maryland Department of Natural Resources reported the first sighting of the tick species in the state on a white-tailed deer in Washington County; presence of the tick was confirmed on July 27.

To date, there are no known direct links between the cases seen in the 8 states.

The USDA has warned that the tick poses a serious threat to livestock because heavy infestations can result in stunted growth, decreased production, and animal deaths. The current host list for this tick includes dogs, cows, goats, sheep, white-tailed deer, opossums, raccoons, and horses. The adult longhorned tick is described to be dark brown in color and very difficult to see with the naked eye; however, when fully engorged, it is known to grow to the size of a pea.

“It is an aggressive biter and frequently produces significant infestations on domestic hosts causing great stress, reduced growth and production, and exsanguination,” the North Carolina Cooperative Extension warns. “As the tick can reproduce parthenogenetically (without a male), a single fed female tick can create a local population quickly.”

The tick has been found to be susceptible to common acaricides that are used to control other tick species in the United States, but because it is known to infect several hosts, managing the species and eliminating it from an environment will be challenging.

Individuals should continue to use standard tick avoidance strategies and farmers should work with their veterinarians to check their livestock for ticks and ensure that parasite control plans are in place. If a longhorn tick is suspected, collect the tick for animal health officials to identify.

Picture Source: New York State Department of Health. Caption: Top row: black-legged/deer tick nymphs and adults, Middle row: Poppy seeds, Bottom row: Nymph and adult longhorned ticks