The Denver Post reports that anthrax has been confirmed in at least one of 50 head of cattle found dead on a ranch in northeast Colorado — the first anthrax case in the state in 31 years.

Authorities have quarantined the affected ranch and notified nearby ranchers of the threat, Colorado state veterinarian Keith Roehr told the newspaper.  He said no cattle left the ranch northeast of Sterling prior to the quarantine and no infected cattle entered the food chain.

State health authorities said they are working quickly to keep the bacterial disease from spreading beyond the ranch. From The Post story:

"Our focus is on the potential for human exposure," said Dr. Tony Cappello, district public health administrator for the Northeast Colorado Health Department.

His investigation includes interviewing anyone who came in contact with the infected herd.

"Anthrax is not spread from person-to-person, and exposure is limited only to those who had contact with the affected cattle or the immediate area," Cappello said.

Roehr, the state veterinarian, said anthrax can develop naturally in soils during a drought.