In the USA, another person tested positive for bird flu after coming into contact with cows. This is the second infection in a human in connection with the current outbreak in several states in dairy cows, the CDC announced. The infected person is an employee of a dairy farm in the US state of Michigan where the virus was detected in cows.

The infected person had symptoms in his eyes similar to conjunctivitis, and an eye swab yielded a positive test result, the health authority said. The new infection does not change the fact that the risk of bird flu to humans in the USA is assessed as low. 

The H5N1 virus was first discovered in dairy cows in the USA at the end of March. According to the US Department of Agriculture, the cows were probably infected by wild birds. At the beginning of April, the US authorities reported a positive case in a person in the state of Texas. The person had previously had contact with dairy cows in which the highly pathogenic H5N1 virus was suspected.

The US authorities believe that this was probably the first human infection via a cow. As early as 2022, the authorities in the state of Colorado registered a bird flu infection in a person. At that time, the patient had previously been in direct contact with poultry and was probably infected through that. 

Largest wave of bird flu ever documented

Bird flu or avian influenza – like flu in humans – is caused by influenza A viruses, but through various other subtypes. The largest wave of bird flu ever documented is currently raging across almost the entire world and also affecting Europe. The pathogen primarily affects birds, but has also been found in many mammals, including cats, bears and seals.

Human infections only occur sporadically. Symptoms range from eye or respiratory infections to serious illnesses such as pneumonia, which can lead to death, according to the CDC. Health experts warn of the danger that the virus adapts to humans and can then be transmitted from person to person.