SPRINGFIELD, Ill. – With the early-May discovery of three Asian longhorned ticks (Haemaphysalis Longicornis) in Randolph County, cattle farmers in southern Illinois and 19 other states are on the lookout for the invasive insect which, during infestations, can inflict livestock losses.

“This tick is a little unique in that it has the ability to reproduce without mating, and the female can lay up to 2,000 eggs at a time. So, there’s always a concern that an area with this tick can become badly infested,” said Dr. Mark Ernst, Illinois State Veterinarian with the Illinois Department of Agriculture (IDOA).

Ernst recommends livestock producers step up their herd inspections to include closer scrutiny of the ears, tail and brisket areas. Because the Asian longhorn tick is extremely small, more time and scrutiny will be required to perform inspections of cattle.

“These ticks can be the size of a sesame seed, really small. When they are engorged with a blood meal, they can get up to the size of a pea,” Ernst said. “Producers need to talk with their veterinarians about a good tick control program.”

The ticks found in Randolph County were discovered as part of the Illinois Department of Public Health’s (IDPH) active tick surveillance program in the area. The first tick was discovered on April 12, with two more confirmed on April 24. The species of the tick was confirmed on May 6 by the National Veterinary Services Laboratory in Ames, Iowa. 

The IDPH, IDOA and the Illinois Department of Natural Resources are now actively monitoring the spread of the Asian longhorn tick in cooperation with the USDA. 

“In some cases of severe H. longicornis infestation, livestock death has been reported,” Ernst said.

The University of Illinois Extension’s Theresa Steckler advises producers to apply EPA-registered insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), para-menthane-diol (PMD) or 2-undecanone to cattle, as directed by product instructions.

The Asian longhorn tick was first confirmed in the U.S. in 2017 in Hunterdon County, N.J., before migrating to other eastern states. The Randolph County reports were the first confirmed cases of the tick variety in Illinois.

According to USDA’s Animal and Plant Health Inspection Service (APHIS):

- Unfed Asian longhorned ticks are light reddish-tan to dark reddish with brown, dark markings.

- Adult females are grey-green with yellowish markings and the size of a pea after feeding. Male ticks are rare.

- Other unfed stages of the tick are very small, about the size of a sesame seed, or even smaller.

APHIS describes the native range of the tick species as including eastern China, Japan, the Russian Far East, and Korea. It has spread to Australia, New Zealand, and several island nations in the western Pacific Region.

In the U.S., Asian longhorned ticks have been collected since 2017 in the following states: Arkansas, Connecticut, Delaware, Georgia, Indiana, Kentucky, Maryland, Massachusetts, Missouri, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Virginia, West Virginia, and now, Illinois.

 It is unclear whether the insect poses a threat to humans. 

“Although the role that this tick will play in the transmission of infections in humans is yet to be determined, the Department of Public Health is working closely with the Department of Agriculture to monitor the presence of the tick and investigate the risk it carries to both humans and livestock,” stated IDPH Director Dr. Sameer Vohra, in an Illinois e-News release.

Illinois producers and others who suspect they have identified Asian longhorned ticks should place the insect(s) in a jar with isopropyl alcohol and contact the IDOA at 217-782-4944.