Asian Longhorned Tick on Cow in Northern Kentucky

A large number of Asian longhorned tick (ALT), Haemaphysalis longicornis, has been confirmed from a dead, emaciated cow in Boone County on July. ALT, native to East Asia, was found in 2017 in the United States, where it infested sheep on a farm in New Jersey. Since its introduction into the U.S., this species has further been detected in Arkansas, Connecticut, Delaware, Kentucky, Maryland, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Virginia, and West Virginia. This is the first exotic species of tick to become established in the U.S. in about 80 years.


ALT feeds on a wide range of birds and mammals, including people, livestock, wildlife, and pets. The most common animals that they have been collected from are dogs, white-tailed deer, humans, raccoons, and cows. In Kentucky, it has been collected from Boone, Floyd, Madison, Martin, and Metcalf counties on cow (twice), bear, human, and elk hosts.

Figure 1. The adult Asian longhorned tick is similar in size to black-legged tick (just over 3 mm in length), but much smaller than lone star or dog ticks. Note the ‘horn’ on the side of the mouthparts (blue arrow). (Photo: Ric Bessin, UK)

Asian Longhorned Tick Basics

ALT is small in size compared to native ticks and is a 3-host tick.  Three-host tick species usually seek a new host to feed with each stage, and then return to the ground to either molt to the next stage or lay eggs. ALT spends 90% of its life off animals. Larvae, commonly called seed ticks, often feed on smaller hosts. The nymph and adult stages feed on larger animals, including humans and cattle. With ALT, all three stages can be found on the same medium-to-large host. Cattle in confined pastures may be infested with all life stages. This tick is parthenogenic; that is, it reproduces without mating and may produce 2,000 or more eggs at a time. A single female tick can create an established population in a new location in just a few weeks, but it takes about 6 months to complete its life cycle. We should expect about one generation per year in Kentucky.

Figure 2. The engorged female (right) can be three to four times the length of a non-engorged female (left).

Potential Issues with ALT in Kentucky

Livestock on pasture are particularly vulnerable to tick infestations. Severe uncontrolled tick infestations in cattle can cause anemia, weakness, blood loss, and possibly death. Production losses including decreased milk production and growth can be substantial.

Monitoring for ALT

Examining animals on a regular basis is critical and the simplest and best way to monitor for ALT and other ticks. Manually remove any attached ticks. Keep in mind that there are several species of ticks that occur on cattle, so you should collect and submit suspicious ticks for identification. When collecting samples for identification, carefully use tweezers to pull off attached ticks in order to collect the mouthparts. Mouthparts are needed for taxonomic identification.


Cattle in high humidity areas or in wooded or tall grass areas are more likely to encounter ALT as dehydration can limit tick populations. Minimize tick habitat in pastures by keeping grasses and weeds trimmed.

Treating livestock with pyrethroid sprays or pour-on insecticide will provide protection for those animals. Whole-animal insecticide treatments can be used for some livestock. Typical tick insecticide treatments, including ear tags, sprays, dips, pour-ons, backrubbers, dust bags, and powders, are effective against ALT. Refer to ENT-11 for a list of options. Discuss any pesticide treatments with your veterinarian or local Extension agent before applying any treatment and ask for recommendations that fit your needs. All pesticides must be used according to the product label.

To protect yourself, you should conduct regular personal tick checks after being outside in tick habitat. Permethrin-treated clothing and DEET, picaridin, or IR3535 can be used as personal repellents. Fipronil-based or similar products can be used for companion animals. Regardless of repellent use, regular self-examination for ticks is recommended when in tick habitat.

Perimeter applications of an insecticide can be applied in areas where ticks may be encountered. Some products are restricted-use requiring pesticide applicator certification. Be sure to follow all label instructions.

By Ric Bessin and Jonathan Larson, Entomology Extension Specialists

Posted in Livestock Pests
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