ST. LOUIS COUNTY, Mo. – A research team with Washington University recently confirmed the presence of an invasive longhorned tick in St. Louis County, marking the first such discovery of the species in the region.

The longhorned tick, known scientifically as Haemaphysalis longicornis, is native to Eastern Asia and was first identified in the United States in 2017. These ticks are light brown and very small, about the size of a sesame seed.

This tick poses a serious threat to livestock in the United States as it can cause large infestations and lead to blood loss in animals. It is also capable of transmitting diseases that impact both animals and humans.

In Missouri, six sightings have now been reported since 2021. The first five were identified in rural Missouri counties, though the latest discovery is the first in a more suburban area of the state, according to a news release from Washington University.

Washington University says it is working with partners at the U.S. Department of Agriculture (USDA) and St. Louis County to track the spread of longhorned ticks.

“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.

Ongoing research efforts include expanding tick collection to study the longhorned tick’s ecology and its potential to transmit local pathogens.

Meanwhile, residents are encouraged to wear repellant, treat their clothing with permethrin and regularly check for ticks after spending time outdoors. St. Louis County also has a tickwatch dashboard to track the presence of ticks locally.