California: Dairy Workers Test Positive for Tuberculosis

Sixteen dairy workers in Tulare, Calif., have tested positive for TB, but county health officials say it's not known whether they contracted the bacteria from an infected herd or another source.

Results of a skin test showed the workers contracted the bacteria but none has an active form of TB, said Dr. Michael MacLean, Tulare County health officer. MacLean said it was difficult to determine whether the workers contracted the bacteria from drinking unpasteurized milk from an infected herd or from their home country. All had lived in Mexico, where TB is common. The tests also do not distinguish whether this was human TB or bovine TB, which has infected cows in Tulare County.

While people can contract TB from drinking unpasteurized milk, MacLean said the chances are small. About 10 percent of those infected with the bacteria will develop symptoms in their lifetime. Six family members who also drank unpasteurized milk were tested and did not show signs of the bacteria, MacLean said. The infected workers will be treated with antibiotics.

State agriculture officials are awaiting test results for 200 cows sold from an infected Tulare County dairy. The cows have been traced to 44 dairies in the county. Farm employees and the processor that buys milk from the dairy have been notified. Bovine TB was last found in the state in 1991. People can contract the disease by working closely with infected cows, drinking raw milk or eating uncooked meat from infected cows. Nearly all milk sold in California is pasteurized, and meat is inspected before being sold.

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