MINNEAPOLIS (AP) — Cattle in Minnesota are keeling over and dying — a phenomenon that health officials warn has been caused by rabid skunks infecting animals and driving up rabies cases in parts of the state.

Minnesota Board of Animal Health data made public Friday by the Minneapolis Star Tribune reports 32 cases of rabies across the state this year. Last year, there were 20 cases over the same period. The spike is concentrated in southwest and central Minnesota, driven by rabid skunks.

“This is a significant increase compared to other years,” Minnesota Department of Health epidemiologist Carrie Klumb told the newspaper. “This is not a normal year.”

At least 24 people exposed to rabid animals this year have been advised to get rabies shots, Klumb added.

In a typical year, the state will see three to five rabid skunks, Klumb said. But the state has already surpassed that figure this year, with 12 infections recorded as of August. Over the last decade, the state has averaged one case per year of rabid cattle, but there have been six infections so far in 2024. All six died.

Rabid skunks can become fearless and aggressive, biting much larger animals such as livestock, according to the state animal health board.

Minnesota experienced an unseasonably mild winter, which may be leading to more rabid skunks, said Erik Jopp, assistant director of the Minnesota Board of Animal Health. During warmer winters, the animals can remain active instead of hiding from the elements, he added.

Officials advise Minnesota residents to avoid skunks this summer and consider vaccinating their pets and livestock if they haven’t already.