According to a recent article in The Culpeper Star-Exponent researchers believe the protozoal parasite, named Theileria orientalis (Ikeda genotype), is transmitted through the saliva of the Asian Longhorned tick (Haemaphysalis longicornis), an invasive species, after being attached to its host for two to three days. Experts do not know how the preliminary infected tick arrived in Virginia.
H. longicornis was initially confirmed in Hunterdon County, NJ, on November 9, 2017, on a sheep farm, and a mystery still surrounds its appearance. The species survived the winter and was confirmed again in NJ in April 2018. The Longhorned Tick Now Confirmed: NJ, VA, WV, AR, NC, NY, PA, CT, NH, KY, MD, & TN.
So far, cases of T. orientalis in cattle have been confirmed in at least 21 counties throughout the state of Virginia including Madison, Fauquier, Orange, Greene, and Louisa. Symptoms include jaundice, anemia, lethargy, labored breathing, fever, diarrhea, anorexia, weight loss, and foamy nasal discharge. The disease is believed to cause abortions or stillbirths in pregnant cows, as well as cause a reduction in milk production by lactating cows. By the time cows are symptomatic, it may be too late to save the cow, and death can occur.
No medications exist for treating T. orientalis, and there is no vaccine. There does exist a “semi-effective” drug from New Zealand. It hasn’t been approved in the US and is said to cause issues that keep livestock off the market for up to 18 months.
1. Starexponent.com. New tick-borne disease challenges Virginia cattlemen [Web Article]. Copyright 2020 starexponent.com. https://www.starexponent.com/news/new-tick-borne-disease-challenges-virginia-cattlemen/article_c9d5040c-b4ae-5930-8f13-b036090f45ef.html
2. Bovinevetonline.com. Invasive Tick Carries Foreign Cattle Disease [Web Article]. Copyright 2019 bovinevetonline.com. https://www.bovinevetonline.com/article/invasive-tick-carries-foreign-cattle-disease-0