Oklahoma is the 20th state to confirm the presence of Asian longhorned ticks since they were first spotted in New Jersey in 2017. They’re originally from East Asia but have spread to other parts of the world, including Mayes County in Northeastern Oklahoma.

Like other ticks, they can carry diseases that infect people and animals. But unlike other species, Asian longhorned ticks can reproduce asexually, laying thousands of eggs at a time.

The U.S. Department of Agriculture says these pesky buggers can cause distress when they latch onto hosts in large numbers. After a dairy cow becomes a host, its milk production can drop by 25%. The ticks also spread theileria, a disease that can cause severe anemia and even death in cows.

The Oklahoma Department of Agriculture, Food and Forestry has launched an epidemiological investigation to figure out how the ticks arrived in Oklahoma and how widespread they are. The agency asks ranchers to contact their county’s OSU Extension Office for instructions if they find unusual-looking ticks on their livestock.