First human death from bird flu subtype is recorded in Mexico, officials say

The first deadly human case of a subtype of bird flu has been confirmed in Mexico, the World Health Organization announced Wednesday.

On May 23, Mexican health authorities reported the death to the WHO, marking the first human death from the avian influenza A(H5N2) virus, according to a WHO news release.

A 59-year-old Mexican resident had developed a fever, shortness of breath, nausea, diarrhea and malaise by April 17, officials said. The unnamed individual was hospitalized in Mexico City on April 24 and died that same day. Notably, the person had underlying medical conditions and had been bedridden for three weeks for other ailments before the new symptoms appeared, family members told health officials.

The source of lethal exposure is unknown, but the virus had previously been detected in poultry in Mexico. According to the WHO, the current risk to the general population is low based on a recent assessment.

“Available epidemiological and virological evidence suggests that A(H5) viruses from previous events have not acquired the ability to sustain transmission between humans, thus the current likelihood of sustained human-to-human spread is low,” the WHO said.

No other individuals infected with this strain of bird flu were found during the WHO’s investigation. Twenty-nine people who came in contact with the infected person, either in the hospital or in the person’s neighborhood, tested negative for the flu and for COVID-19.

The bird flu subtype was initially detected in March in a backyard poultry farm in Michoacán, the state bordering the one where the infected person lived, according to officials.

Health authorities are continuing to monitor people who had contact with the infected person, watching for flu outbreaks in neighboring municipalities and urging environmental and animal health officials to watch for infections in poultry and wild birds near where the patient lived.

According to the WHO, people have caught bird flu through direct contact with infected birds or “contaminated environments.” The infections may cause upper respiratory tract infections that can be fatal, as well as conjunctivitis, gastrointestinal symptoms, encephalitis and encephalopathy, the WHO says.

At this point, there are no approved vaccines for humans to protect against bird flu, although some candidates are in development.