First Human Fatality From Bird Flu Strain Reported By WHO: Patient in Mexico Dies

A Mexico resident has died from what officials say is the world's first death caused by a bird flu strain not previously detected in humans, the World Health Organization (WHO) announced on Wednesday.

The 59-year-old passed away on April 24 after experiencing fever, shortness of breath, diarrhea, nausea, and general discomfort for a week, according to the WHO. The individual, whose identity has not been disclosed, had multiple underlying health conditions before the onset of acute symptoms.

The patient had been bedridden in Mexico City for three weeks before succumbing to complications from the infection.

Laboratory results confirmed that this was the first human death due to the avian influenza subtype A(H5N2), as well as the first human H5 virus infection reported in Mexico, according to the WHO. The source of the individual's exposure to the virus is unknown, as the patient had no prior contact with poultry or other animals.

In Mexico, cases of the A(H5N2) strain of bird flu have been identified in poultry.

In the United States, at least three human cases of bird flu have been linked to work on dairy farms, but these were caused by a different subtype of the virus (H5N1), health officials noted.

The risk to the general population is minimal

The H5N2 strain is distinct from other avian influenza cases that have led to a multi-state outbreak in cattle since late last year.

WHO officials have stated that the current risk to the general population is low based on available information.

"This case does not change the current WHO recommendations on public health measures and surveillance of influenza," the organization wrote. According to the WHO, scientists will conduct an epidemiologic investigation in any case of a "confirmed or suspected human infection caused by a novel influenza A virus with pandemic potential," including bird flu. These experts will also analyze unusual events that could indicate person-to-person transmission of the virus and collect clinical samples.

What Is Bird FLU?

Bird flu, or avian flu, is a contagious infection that spreads among wild birds and can infect domestic poultry and other animal species. While the virus does not often spread to humans, sporadic infections have been reported. There are several strains, all belonging to influenza A-type viruses. The most common subtypes that may affect humans are A (H5N1), A (H7N9), and A (H9N2), according to the Cleveland Clinic.

In humans, symptoms can resemble typical flu but may progress to more serious respiratory issues.

In birds, avian flu is highly contagious, with cases ranging from mild to highly deadly. Infected birds shed the virus in their saliva, nasal secretions, and feces, allowing other birds to contract the virus through direct contact with these fluids or contaminated surfaces. The CDC has documented three cases of human bird flu infections in 2024: two in Michigan dairy farm workers and one in a dairy farm worker from Texas.