US records first case of highly contagious H5N1 bird flu

The case comes amid concerns that a continuing outbreak among US birds could lead to more human infections.

The first known human case of H5N1 bird flu in the United States has been detected in a person in Colorado, according to the Centers for Disease Control and Prevention (CDC).

The person tested positive after being involved in the culling of poultry presumed to have had H5N1 bird flu, the CDC said in a statement. The infection comes amid a wider outbreak of the particular strain of bird flu in the US.

The agency said that the case was only the second human infection globally with the specific group of H5 viruses, with the first detected in the United Kingdom.

“This case does not change the human risk assessment for the general public, which CDC considers to below,” the agency said.

The agency began monitoring people believed to be exposed to the virus in 2021. It has been detected in commercial and backyard birds in 29 states in the US and in wild birds in 34 states.

The outbreak has resulted in the culling of millions of chickens and turkeys across the US.

Health experts have voiced concern that the continued spread of the virus could lead to mutations that more easily spread to humans.

A previous outbreak of the H5 virus in the US occurred in 2015, but no cases were detected in humans, according to the CDC. Several countries detected outbreaks of H5N1 in poultry last year.

The infected patient-reported fatigue for a few days as the only symptom and has since recovered, the CDC said, adding that the person was being isolated and treated with the influenza antiviral drug oseltamivir.

“CDC has tracked the health of more than 2,500 people with exposures to H5N1 virus-infected birds and this is the only case that has been found to date. Other people involved in the culling operation in Colorado have tested negative for H5 virus infection, but they are being retested out of an abundance of caution,” the CDC said.