6 Things You Need to Know About the Asian Longhorned Tick

A new tick species known as Haemaphysalis longicornis, or the Asian longhorned tick, has made its way into the United States, making it the first new invasive tick species found in North America in close to 50 years.

Ticks have become a growing concern for public health officials as tick bites and tick-borne diseases more than tripled in the United States between 2004 and 2016 according to the Centers for Disease Control and Prevention (CDC). There were more than 70,000 cases of diseases spread by ticks in this country in 2016.

The Asian longhorned tick is concerning because it can carry a virus that’s caused illness and even death in people in eastern Asian, says Mark J. Soloski, PhD, professor of medicine at Johns Hopkins Medicine in Baltimore. “Fortunately, there have been no pathogens found to be associated with this particular tick so far in the United States,” he says.

Although this is good news, the potential for the tick to carry diseases that could infect humans and animals here has health officials keeping a close eye. Here are six things that experts know so far about the Asian longhorned tick:

1. In what states have Asian longhorned ticks been spotted?

According to the CDC, the tick has been found in New York, Pennsylvania, Connecticut, New Jersey, Maryland, West Virginia, Virginia, North Carolina, and Arkansas.

A CDC-sponsored study, published in April 2019 in the journal Emerging Infectious Diseases, found that the tick could likely spread and live throughout most regions in the United States because of a “combination of suitable habitat types, a plethora of host species, and high humidity.”

2. Has the tick made people sick in other parts of the world?

In Asia, the tick carries a virus that causes human hemorrhagic fever, which can be life-threatening. In 2013, South Korea had 36 reported cases of severe fever with thrombocytopenia syndrome (SFTS), including 17 deaths from SFTS virus, carried by the Asian longhorn tick. Thrombocytopenia means low levels of platelets, which are necessary to help the blood to clot normally; a major drop in platelets can cause internal bleeding and organ failure. Besides fever, symptoms included gastrointestinal symptoms and fatigue, according to the abstract of a study published in November 2014 in Emerging Infectious Diseases.

In Australia and New Zealand, the ticks feed on livestock and can cause babesiosis and theileriosis, but don’t carry any diseases to humans.

3. Is there a risk the ticks will eventually spread viruses and bacteria here?

A tick bite only makes a person sick if the tick is carrying a pathogen that it picked up from a blood meal on another host, says Dr. Soloski. “For example, in human Lyme disease, the tick that most likely transmitted the disease to a human acquired the bacteria from a prior blood meal from a mouse,” says Soloski. The tick has to get the infection from feeding on another host in order to pass it on to humans via a tick bite, he explains.

So far, no Asian longhorned tick that’s been found and analyzed in the United States has had any pathogens found associated with it, according to Soloski. "It’s possible that the Asian longhorned tick found here won’t carry the same types of pathogens (or any pathogens) as it has in other parts world, but we are paying attention to it," he says.

One reason health officials are concerned is that the SFTS virus that this tick can carry is related to the Heartland virus (they both belong to the genus Phlebovirus), which is found in the Midwest and Southern U.S. states and is transmitted by the lone star tick.

4. How do these ticks differ from other ticks found in the United States?

"Most ticks, such as the deer tick (which can transmit Lyme disease), produce eggs through male and female mating, then the fertilized eggs are generated,” says Soloski. In the case of the Asian longhorned deer tick, it has evolved parthenogenesis, which means it produces fertile eggs without having the need for a male around, he says. “That’s a concern because then these ticks can produce large numbers of eggs in a very short period of time and spread quite quickly,” says Soloski.

According to the CDC, a single female tick can reproduce up to 2,000 eggs at a time without mating. As a result, hundreds to thousands of ticks can be found on a single animal, person, or in the environment. Because of the sheer numbers of ticks that can prey on hosts, this tick can reduce production in dairy cattle by 25 percent.

5. Do the standard precautions for tick prevention work for the Asian longhorned tick?

Studies are ongoing to determine how well tick prevention products currently available in the United States will work against Asian longhorned ticks, says CDC spokesperson Thomas Skinner.

For now, Skinner and Soloski suggest taking typical measures that the CDC recommends to prevent tick bites. Soloski recommends being “tick savvy,” which includes commonsense clothing, tick repellent, and frequent tick checks when spending time outdoors.

6. What should you do if you suspect you or your pet has been bitten by an Asian longhorned tick?

If you find a tick attached to your skin or on your pet, you should safely remove the tick as soon as possible, according to the CDC. Save the tick in rubbing alcohol in a jar or ziplock bag and contact your health department, doctor, or veterinarian.

If you find a tick on yourself or your pet and think it might be an Asian longhorned tick, you should also try to contact your local agricultural extension office and tell them, says Soloski. “That’s one way we get information: It’s called citizen science,” he says.

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