A man in Mexico has become the first known human case of contracting the H5N2 bird flu strain, which had never before been identified in a human. The man, who was bedridden with underlying health conditions including chronic kidney failure, diabetes and high blood pressure, developed a fever, shortness of breath and diarrhea on April 17. Mexican health officials alerted the World Health Organization (WHO) to the case after his death on April 24. Initial tests showed an unidentified type of flu that subsequent weeks of lab testing confirmed was H5N2.
The WHO stated that there is a low risk to people in Mexico, and no further human cases have been discovered so far despite testing people who came in contact with the deceased at home and in the hospital. However, authorities are closely monitoring birds near a shallow lake on the outskirts of Mexico City as there had been three poultry outbreaks of H5N2 in nearby parts of Mexico in March.
H5N2 is not the same strain that has infected multiple dairy cow herds in the US, which is called H5N1. While other bird flu varieties have killed people across the world in previous years, including 18 people in China during an outbreak of H5N6 in 2021, there are numerous types of bird flu and they can sometimes pass from animals to humans.
The man's underlying health issues likely made him more susceptible to the virus. Bird flu viruses normally circulate in birds but occasionally can jump to other species, including humans. People catch the viruses from direct contact with infected animals or contaminated environments.
Depending on the original host, type A flu strains can be classified as bird flu, swine flu or other types of animal influenza viruses. Bird flu infections in humans can cause mild to severe upper respiratory tract infections and can be fatal. Eye infections like conjunctivitis, gut symptoms and brain swelling are also possible.
The WHO is closely monitoring H5N2 and other strains of bird flu for any signs that they are evolving to spread easily from person to person. Experts are concerned as more mammal species contract bird flu viruses.
