A new tick plus a new disease equals a double threat to Virginia cattle

A new tick plus a new disease equals a double threat to Virginia cattle
Asian longhorned tick. (Source: (Kevin Lahmers, Virginia Tech))

The cause of the seven cows’ deaths wasn’t immediately clear.

All of the animals died between late summer and fall of 2017 in Albemarle County, the prosperous, semi-agricultural county that surrounds the city of Charlottesville. Another cow on the property, sick but alive, was found with signs of anemia, weakness and respiratory distress.

Fearing the deaths were a sign of a new foreign animal disease, the U.S. Department of Agriculture came to Albemarle to investigate and found that six other cattle on the farm were infected with Theileria (pronounced tie-lee-ree-uh) orientalis, a fairly benign disease known to infect livestock in the U.S. But a later study done at Virginia Tech that looked at the form the Theileria took made a startling discovery: rather than the more common strain scientists were accustomed to seeing in North America, the disease infecting the Albemarle cattle was a virulent form known as the Ikeda subtype.

Ikeda had never before been detected in the Western Hemisphere. And investigators weren’t happy to see it. Studies from New Zealand have found that about 5% of cattle infected with this subtype die; those that survive often grow more slowly, produce less milk and are more likely to miscarry their calves. In Australia, this results in an estimated $20 million worth of cattle losses annually; in Korea and Japan, that number may be as high as $100 million.

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