By Dr. Chris Blevins, equine field service
During the winter we rarely think about ticks. In most cases ticks are only a problem in the warmer seasons of spring, summer and fall. However, horse owners are noticing a lot of ticks on their horses this winter. This “winter tick”, also known as the Ghost Moose Tick, is different than the tick we see in the summer months. The scientific name is Dermacentor albipictus. Its nickname comes from the primary host the moose, however other species of animals (like horses) can become the host. Ticks infesting a moose can cause anemia and even death. In recent years, more than 75,000 ticks have been found infested on one moose.
|Paper trays with hundreds of winter ticks pulled off a horse in Kansas.|
The lifecycle of the winter tick is different than the more common summer species of ticks. The winter tick is a one-host tick, which will live on same host from larvae to adult. The eggs hatch on the ground in mid-summer and set dormant before migrating to taller vegetation in clusters. Once on the taller vegetation, the larvae then latch onto an animal as it walks by. The larvae can become a nymph on the host animal within 10 days. The nymph remain dormant on the host until winter when they become an adult. Adult ticks are easier to see and feed on the blood of the host for the rest of the winter. The adults mate, and females lay eggs on the ground in the early spring time.
Treating horses with these ticks can be tough, like any other tick found on horses. However, some products are good for killing these ticks on cattle and horses. Coumaphos (Co Ral® Fly and Tick spray by Bayer) is one product that has been shown to work. Please work with your veterinarian for the use of this product. It is important to follow veterinary instructions (amount and frequency) to prevent toxicities, other side effects and environmental contamination.
Understanding the lifecycle and ecosystems of the winter tick can also help with management. Winters that are shorter and warmer have been shown to correlate with higher infestations on the host (like the moose).
Please contact your veterinarian and/or the Kansas State University Veterinary Health Center with other questions or concerns about the winter tick.
VHC: 785-532-5700 or www.ksvhc.org/services/equine/
Addison et al. (1988). "Growth and Development of Winter Tick, Dermacentor albipictus, on Moose, Alces alces". The Journal of Parasitology. 74 (4): 670–678.
Dell'Amore, C (2015-06-01). "What's a Ghost Moose? How Ticks Are Killing an Iconic Animal". National Geographic News. Retrieved 2019-03-08.