How did cows catch it?

Bird flu was likely originally transmitted to cows by wild migrating birds, according to a USDA memo published April 16. The agency adds there is now evidence of cow-to-cow spread in some recent cases.

The virus may have also spread from dairy cattle to nearby poultry and barn cats on some farms, too, but the exact pathways are not yet known. In the latest cases, the sickened cows have survived but other animals, including cats and poultry, have died.

Compared to birds, cows are experiencing mild symptoms: low energy, fever, dehydration and reduced appetite, plus thick, discolored milk and a decrease in production, the USDA says.

The raw milk of infected cows has been found to contain high concentrations of H5N1 and USDA has warned dairy workers to avoid any exposure to unpasteurized milk. To tamp down the spread, the agency has recommended “particular attention” to disinfecting milking equipment, as well as pens and other surfaces.

In the meantime, the USDA and the FDA both say that pasteurization has proven to kill viruses and bacteria, and there is no risk of infection from drinking commercial milk. And so far, the limited number of cases, plus cows’ relatively quick recovery from infection means there’s no threat to the country’s milk supply, for now.

Raw milk from sick cattle, however, has tested positive for the virus, and the CDC has urged people not to consume raw, unpasteurized milk. Dairy advocacy groups, like the Dairy Alliance, which represents farmers in Georgia and other Southeastern states, are echoing that sentiment.

“With raw milk, it’s always a risk, regardless of this virus,” said Geri Berdak, CEO of the Dairy Alliance, which counts roughly 75 farms in Georgia among its members. “There are absolutely no safety concerns with pasteurized milk.”