CDC Confirms 4th Human Case of H5N1 Avian Flu as More Dairy Herds in Colorado Hit

By Stephanie Soucheray

The Centers for Disease Control and Prevention (CDC) confirmed the fourth human case of highly pathogenic avian flu in the United States this year and the first in Colorado, as the state reported more infected dairy cows. Previous human cases were in Texas (one) and Michigan (two).

In a press release emailed to journalists, the CDC said the Colorado patient is a dairy worker who was being monitored because of work exposure to H5N1 virus-infected cattle. 

"The person reported eye symptoms only, received oseltamivir [Tamiflu] treatment, and has recovered," the CDC said. "Based on the information available at this time, this infection does not change CDC's current H5N1 bird flu human health risk assessment for the U.S. general public, which the agency considers to be low."

The first two agricultural workers infected in the United States, in Texas and Michigan this spring, also reported eye symptoms. 

Two more herds in Colorado affected

The US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) has added two more H5N1 avian flu dairy herd outbreaks to its confirmed list, both in Colorado, raising its total to 139 affected herds from 12 states.

Colorado has had the most affected herds in the past 30 days, with 23 herds affected, APHIS said. 

APHIS also reported H5N1 in 2 more domestic cats since our last report, 1 each in Michigan and Colorado, raising the total to 30 infected cats.

A WOAH (World Organization for Animal Health) notification on the Colorado cat, which is from Adams County, says the cat was exhibiting acute respiratory signs but wasn't associated with any known H5N1-affected cattle or poultry premises.

As more dairy herds have been infected with highly pathogenic avian flu, researchers from the Food and Drug Administration have continued to sample commercial pasteurized milk and conduct experiments that reassure consumers that the pasteurization process used in the United States inactivates H5N1. It is not yet known if drinking raw milk from an infected cow could pass H5N1 to humans, but mouse studies suggest it is possible.

Half of Americans do not understand pasteurization process 

A new survey from the Annenberg Public Policy Center, however, shows that less than half of US adults know that drinking raw (unpasteurized) milk is riskier than drinking pasteurized milk. The survey included 1,031 adults polled from June 7 to June 10. While only 4% of Americans report regularly consuming raw milk products, selling such products is legal in 30 states.

One in five Americans (20%) said they are not sure if pasteurization can kill harmful bacteria and viruses. And 4% of those polls said pasteurization is simply not effective in doing so.

In the poll, over half of the respondents (54%) think that drinking raw milk is either safer (9%) or just as safe (15%) or are unsure (30%) whether it is more or less safe than drinking pasteurized milk. Pasteurization does not lower the nutritional value of milk, but 16% polled believe that it does destroy nutrients, and 41% aren't sure. 

Outside of H5N1, raw milk is estimated to cause 840 times more illnesses and 45 times more hospitalizations than pasteurized products, according to the Annenberg Center.

"It is important that anyone planning to consume raw milk be aware that doing so can make you sick and that pasteurization reduces the risk of milk-borne illnesses," said Patrick E. Jamieson, director of the Annenberg Health and Risk Communication Institute at the Annenberg Public Policy Center (APPC) at the University of Pennsylvania.