Expert describes devastating effects of bird flu as traces of virus are found in fifth of US milk

One in five retail samples of commercial milk has traces of bird flu, the Food and Drug Administration (FDA) said this week.

The avian flu was first detected in Texas herds in March — and it has since been found in more than three dozen herds in eight states, according to the US Department of Agriculture.

“The agency continues to analyze this information; however, the initial results show about 1 in 5 of the retail samples tested are...positive...with a greater proportion of positive results coming from milk in areas with infected herds,” the FDA said.

With the rise in bird flu and its presence on six continents, the “worst case” for livestock is near, according to Maurice Pitesky, a specialist at the University of California, Davis School of Veterinary Medicine.

“[The virus] has demonstrated an ability to move into dairy cows, and while doesn't cause mortality it causes a decrease in milk production, which has economic impacts,” Mr Pitesky told The Independent. “This ultimately will affect the ability to produce fluid milk and all the things that are associated with it.”

This virus could have significant ecological and economic consequences.

“There’s a wildlife scenario that’s also devastating,” Mr Pitesky said. “The virus is affecting sea lions and elephant seals and Albatross and all these other things that are that are their populations are being devastated.”

The only known recent case of H5N1, the specific strain detected, was in a US dairy worker, according to the Centers for Disease Control (CDC). The worker is only the second known person in the US to test positive for the virus.

More dairy workers will continue to face occupational hazards as the virus spreads, Mr Pitesky said.

“Farmworkers are working in these environments with lots of dairy cows that are affected,” he told The Independent. “They're the frontline of surveillance and also the frontline of people that are that are potentially most susceptible to getting sick.”

Now, dairy cattle moving between states have to be tested for the virus to control the growing outbreak. Every lactating cow must now be tested and receive a negative result before moving across state lines. The herds known to carry the virus are located in Idaho, Kansas, Michigan, New Mexico, North Carolina, Ohio, Texas and South Dakota.

Health agencies and experts are emphasising that dairy products are still safe to consume.

“To date, the retail milk studies have shown no results that would change our assessment that the commercial milk supply is safe,” the FDA said.

To stay safe, consumers should drink pasteurised milk, according to both the CDC and experts, which deactivates the virus.

“This is the millionth reason to drink pasteurized milk,” Mr Pitesky told The Independent. “I'd be very concerned for folks that drink raw milk, I think that's a real risk.”

The symptoms of bird flu in humans range from no symptoms to severe symptoms, according to the CDC. These symptoms can include fever, fatigue, and difficulty breathing. Less common symptoms include diarrhoea, nausea, vomiting, or seizures, the CDC said. Human-to-human transmission is also rare.

Egg producers are also on high alert after chickens tested positive for the virus in Texas and Michigan. Officials have killed millions of birds and the FDA maintains the risk of human infection is still low.