H5N2 avian flu: first human case of strain identified in Mexico, according to WHO

CNN
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Even as the United States grapples with an outbreak of H5N1 flu in dairy cattle, the World Health Organization announced the first known human infection with a different strain, H5N2, in a person in Mexico who died from complications of his infection.

These two strains of influenza A virus primarily affected farmed and wild birds, infecting flocks around the world. About 900 human cases of H5N1 have been reported since 1996, and about half of those infected have died. On Wednesday, the WHO announced that it had confirmed the first case of human infection with the H5N2 virus in a 59-year-old Mexican resident.

The source of this person's infection is unknown, although the WHO noted that H5N2 viruses had been reported in poultry in Mexico.

Since any new human infections with influenza A can have a significant impact on public health, they should be reported to WHO. The organization stated that, based on current knowledge, the risk to the general public from H5N2 is low, since other H5 subtypes are known to infect humans, but it has only been shown to none of them cause lasting human-to-human spread.

The person, who had multiple underlying health conditions, had been bedridden for three weeks for other reasons before developing new symptoms. By mid-April, they developed fever, shortness of breath, diarrhea, nausea and weakness. On April 24, they consulted a doctor and were hospitalized at the National Institute of Respiratory Diseases in Mexico City. The person died from complications that day.

On May 8, a sample sent for specialized testing indicated that it was positive for H5N2, and the result was later confirmed by another laboratory.

Of the 17 hospitalized people who were in contact with the patient, no other cases have been identified. Twelve additional contacts were identified near the person's home, and seven of them had symptoms, but testing of samples from these cases did not identify Covid-19 or any type of flu . Scientists are currently testing blood samples to see if they can find antibodies that could indicate previous infections.

In March, an outbreak of H5N2 was reported at a backyard poultry farm in a state neighboring where the person lived. According to the WHO, it has not been possible to establish whether this case is linked to recent outbreaks in poultry.

Influenza viruses normally circulate in birds, but can sometimes be transmitted to other species, including humans. People contract viruses through direct contact with infected animals or contaminated environments.

Depending on the host of origin, type A influenza strains can be classified as avian flu, swine flu, or other types of animal flu viruses.

Avian influenza infections in humans can cause mild to severe upper respiratory infections and can be fatal. Eye infections such as conjunctivitis, intestinal symptoms and brain swelling are also possible.