Apr 2, 2024 - Health

What to know about bird flu

A public health sign warns people about bird flu in May 2022 in Brighton, United Kingdom. Photo: Andrew Aitchison/In pictures via Getty Images

Bird flu is spreading among dairy cows in at least three U.S. states, and one person in Texas has been infected with the virus, health officials said.

The big picture: More than 80 countries have reported bird flu outbreaks in in poultry and wild birds in the past two years, according to the World Health Organization. Ten countries across three continents have reported virus outbreaks in mammals.

  • Outbreaks, which spread rapidly and can cause significant illness and death among poultry, can have major agricultural and economic implications and in rase instances can be transmitted to humans.
  • Cal-Maine Foods, the biggest egg producer in the U.S., said on April 2 that it halted production at a Texas facility after some of its chickens tested positive, leading to the culling of about 3.6% of the company's total flock.

What is bird flu?

Bird flu is a disease caused by infection with avian influenza Type A viruses, per the Centers for Disease Control and Prevention.

  • The viruses are very contagious among birds, and can sicken and kill certain domesticated bird species, including chickens, ducks and turkeys.

How does bird flu spread?

It spreads globally among susceptible birds through contact as an infected bird sheds the virus in its saliva, nasal secretions and feces, according to the CDC.

  • Infections can also occur via contact with contaminated surfaces.

Which animals are most susceptible?

The viruses normally spread among birds, according to the World Health Organization.

Yes, but: An increasing number of aviation flu cases among mammals, including cattle, "raises concern that the virus might adapt to infect humans more easily," the WHO says.

  • Last month, the American Veterinary Medical Association said a goat in Minnesota had become the first domestic ruminant to test positive for bird flu in the U.S.

What threat does bird flu pose to humans?

While human infection is possible, its occurrence is rare.

  • People with close or prolonged, unprotected exposures to infected birds or other animals or to contaminated environments face greater risk of infection.

Threat level: A person in Texas was being treated for the H5N1 strain of the flu after exposure to dairy cattle presumed to be infected with the virus, health officials said Monday.

  • The infection doesn't affect the CDC's current health risk assessment for the public, which is considered low.
  • This case is only the second human case of H5N1 in the U.S., CDC data shows. The first was reported in Colorado in 2022 after the patient was exposed to poultry.

Do outbreaks impact cow milk supply?

The bird flu was recently detected in unpasteurized milk samples and swabs from dairy herds in Texas, Kansas and Michigan.

  • But federal authorities said there is "no concern" about the safety of the U.S. milk supply.
  • Still, the FDA recommends that people avoid unpasteurized (raw) milk and cheese products.

Worth noting: The bird flu outbreak has contributed to rising egg prices.

Go deeper: Person in Texas contracted bird flu after exposure to infected cows

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