The potentially dangerous longhorned tick is spreading in the US

The smaller cousin to the long-horned tick, the deer tick.
The smaller cousin to the long-horned tick, the deer tick.
Image: Photo courtesy of the US Centers for Disease Control and Prevention
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No one’s sure how the longhorned bloodsucker got to America, nor what havoc it might wind up causing there. But scientists across several US states are sounding the alarm about the proliferation of this invasive tick.

Haemaphysalis longicornis, distinguishable from its brethren by its horns, is native to east and central Asia. It somehow made its way across the ocean and into the US, where it is increasingly showing up on farms. New Jersey was the first state to publicly mention the arrival of the tick, announcing earlier this year (pdf) that it had been discovered on sheep in late 2017. It was the first time in about 50 years that a new kind of tick had been found in the country.

Longhorned ticks have subsequently been spotted in New York, Virginia, West Virginia, Arkansas, North Carolina, and Pennsylvania. In a statement to the public, the Pennsylvania state agriculture department cautioned that the arachnid infests its hosts by gathering in dense clusters. Female longhorned ticks are able to reproduce asexually, and can lay up to 2,000 eggs after feeding on a host.

“Scientists don’t yet know how this species will adapt to the North American climate and animal hosts, but we know it survived New Jersey’s winter and has infested sheep and cattle in this region,” said Pennsylvania state veterinarian, David Wolfgang, in a statement. Other species in the US are recognized as vectors for a range of tick-borne illnesses, and can sometimes cause a host animal to develop anemia.

In east Asia the longhorned tick has been known to spread phlebovirus, a virus that can cause a condition called severe fever with thrombocytopenia syndrome (known as SFTS). That, in turn, can create blood-clotting complications that lead to death (paywall) in about 15% of cases, most in older populations. So far, scientists in the US have not seen the presence of phlebovirus or any other tick-borne diseases in the longhorned ticks they’ve tested from across the Eastern seaboard.

Still, it’s worth being extra cautious. Scientists say the best way to prevent getting bitten by a tick is to wear long sleeves and pants when outdoors, paired with the use of insect repellent containing diethyltoluamide, more commonly referred to as DEET. They also suggest regularly checking pets for ticks.