Researchers at Washington University in St. Louis recently identified the first longhorned tick (Haemaphysalis longicornis) found in suburban St. Louis County.
Longhorned ticks are a serious threat to livestock in Australia, New Zealand and countries in eastern Asia. This tick often forms large infestations on one animal, causing great stress and reducing growth and production. A severe infestation can even kill the animal due to blood loss.
Working with partners at the U.S. Department of Agriculture (USDA) and St. Louis County, WashU scientists are continuing to track the spread of longhorned ticks. A recent WashU grant will support longhorned tick investigations in the region.
The longhorned tick recently found in St. Louis County was collected and identified by a WashU undergraduate researcher, Sam Ko, at Tyson Research Center, WashU’s environmental field station, near Eureka, Mo.
“We have only found one longhorned tick in St. Louis County so far, but it’s likely that there are more,” said Solny Adalsteinsson, a senior scientist at Tyson Research Center, who leads the center’s tick and wildlife ecology team.
Officials collected the first longhorned tick in the state in May 2021. There have been few others reported since then; all five confirmed reports before this new one have been in rural counties.
Longhorned ticks are light brown and very small, about the size of a sesame seed. Because these ticks are so small, cows or other livestock can potentially host thousands of longhorned ticks. In other countries, longhorned ticks have been known to transmit diseases that impact livestock and humans.
“The notable thing about a longhorned tick is that it doesn’t need to reproduce sexually. A single female is all that is needed to establish a new population,” Adalsteinsson said.
Expanding tick collection efforts
This spring, WashU researchers are expanding their tick collection efforts to learn more about the longhorned tick’s establishment and ecology in the region — as well as its capacity to transmit local pathogens — with support from a Transcend Initiative Grant award from WashU’s “Here and Next” Seed Grant program to Adalsteinsson; Jacco Boon, a professor of medicine, of molecular microbiology and of pathology & immunology at WashU Medicine; Michael Landis, an assistant professor of biology in Arts & Sciences; and Susan Flowers at Tyson Research Center.
The team also will partner with St. Louis County on its effort to collect and identify ticks through its community science project Tick Watch STL.
“We started accepting tick submissions in April 2024,” said J. Brooke Dedrick, a vector-borne disease prevention specialist with St. Louis County’s Department of Public Health. “Residents can mail us ticks or drop them in drop boxes (located across the county) for us to identify. There is a collection form that tells us where the tick was collected. This information guides us to the area of interest, where we can then conduct active tick surveillance.”
In addition to Adalsteinsson sharing tick collection data with the county, Boon and Whitney Anthonysamy, at University of Health Sciences and Pharmacy (UHSP), will test ticks submitted to Tick Watch STL for viral and bacterial disease-causing pathogens, respectively. Anthonysamy’s work is supported by a Faculty Research Incentive Fund Award from UHSP.
The county also published a public data dashboard for the Tick Watch STL project that includes a tick collection map with detailed information about ticks collected by residents, as well as those from county surveillance efforts. “We want to give residents the tools to make decisions in their best interest and let them know that we are here for them when they have questions or need support,” Dedrick said.
Adalsteinsson and Dedrick note that although February and March are months with lower tick activity, there are still things local residents can do to reduce their tick risks.
“With increased awareness, we hope that we are empowering people to take steps to mitigate tick bites, such as wearing repellant, using permethrin on their clothing, conducting tick checks and performing habitat management,” Dedrick said.
