Bird flu spreads across US among poultry and dairy farms

Sixteen human cases of avian influenza have been reported in the United States this year, including last two employees who tested positive in California. Fifteen of these cases occurred in workers from contaminated poultry or dairy farms. Health authorities say the risk of bird flu to the public is low.

The sick workers had only conjunctivitis and no respiratory symptoms, said Nirav Shah, principal deputy director of the CDC.

More than 250 dairy herds in 14 states have tested positive for avian influenza this year, including 56 in California, according to the USDA.

The CDC is still investigating whether any health care workers may have been exposed to bird flu after a person in Missouri tested positive, Shah said.

Possible outbreak

Tests the agency is conducting on seven blood samples from health care workers exposed to the sick person to determine whether they were previously exposed to the virus could take another two weeks, he said.

The strain of avian flu found on two farms in California is the same as on dairy farms in other states, and the affected farms are under quarantine, said Eric Deeble, USDA deputy assistant secretary for marketing and regulatory programs.

Colorado, which was a hot spot for avian flu on dairy farms in the spring, now has just one positive herd, indicating the success of the state’s mandatory milk testing, Deeble said.

Pasteurization destroys the virus.

Pasteurized dairy products remain safe for consumption, Steve Grube, chief medical officer at the Food and Drug Administration’s Center for Food Safety and Applied Nutrition, said on a conference call.

The FDA announced it will begin a study of raw cow’s milk at some dairies to better understand the prevalence of avian influenza virus in the milk supplied.