Chronic wasting disease turned up on farmed white-tailed deer in three Michigan counties this week, two of them for the first time. [1]

The Michigan Department of Agriculture and Rural Development confirmed the fatal, prion-based neurologic disease in Calhoun, Kent and Mackinac counties. Kent County has recorded CWD before, in both farmed and free-ranging deer. Calhoun, in southwestern Michigan, and Mackinac, on the Upper Peninsula, had never detected it on a deer farm until now. [1] Routine surveillance caught the Calhoun and Kent cases first; the Calhoun finding led investigators to the Mackinac detection. The infected deer were 2.5, 3, and 4 years old.

"These detections highlight why it is so vital to perform regular surveillance testing," State Veterinarian Nora Wineland said in a release. "Early detection allows for a prompt response, which helps limit the exposure of additional animals to this disease." [1] CWD spreads between cervids through infected saliva, urine and feces, environmental contamination, and from does to offspring during pregnancy. It has no known effect on humans, but health agencies advise against eating meat from infected or sick animals and recommend testing cervids harvested in CWD-endemic areas.

The detections make Michigan the site of two distinct animal-disease surveillance stories this week — CWD on deer farms and, separately, the nation's largest Cyclospora cluster, tied to Michigan-area lettuce and now above 17,000 cases nationally. [1]

-- DARA OSEI, London