First Human Death from H5N2 Bird Flu Confirmed in Mexico by WHO
The World Health Organization (WHO) announced the first known human death from the H5N2 strain of bird flu in Mexico. This is the world's first laboratory-confirmed human infection with the H5N2 virus, affecting a 59-year-old man from the State of Mexico.
The victim had no history of contact with poultry or other animals, making the exact source of the infection unknown. The WHO's statement notes that infection in humans with a new subtype of this virus could potentially have a significant impact on public health. However, the risk to the population is considered 'low' for now.
The individual had multiple underlying medical conditions and was bedridden for three weeks with symptoms such as fever, difficulty breathing, diarrhea, nausea, and general malaise. On April 24, he sought medical attention and was hospitalized at the Ismael Cosío Villegas National Institute of Respiratory Diseases in Mexico City. He passed away the same day due to complications.
On May 23, the Mexican health authorities informed WHO about the confirmed human infection. A specialized test conducted on May 8 initially indicated H5N2, which was subsequently confirmed by an additional laboratory. Despite the man's lack of direct contact with poultry, outbreaks of the H5N2 virus were reported in backyard poultry farms in neighboring regions, including Michoacán and Texcoco.
The WHO has confirmed that of the 17 individuals who came into contact with the patient at the hospital, none were found to be infected. Similarly, no additional cases were detected among 12 additional contacts near the man's residence, although seven displayed symptoms. Tests for Covid-19 and other types of flu conducted on these cases returned negative results.
According to the WHO, previous outbreaks of H5N2 and other strains of avian influenza like H5N1, H5N6, and H5N8 have affected both wild and farmed birds globally. While rare, animal-to-human transmission is possible through direct contact with infected animals or contaminated environments. Fortunately, there is currently no evidence to suggest that H5N2 has acquired the capacity for sustained human-to-human transmission.
- Influenza viruses typically circulate among birds but can occasionally infect other species. Past outbreaks have shown that different strains like H5N1 have severe effects on human health, causing both mild and severe upper respiratory tract infections. They may also lead to more serious conditions like conjunctivitis, intestinal symptoms, or brain inflammation.
- In the United States, an outbreak of the H5N1 strain in dairy cows has been ongoing. Although there have been several human cases reported, there is no evidence linking these infections to the animal outbreak, and no human-to-human transmission has been confirmed.
- In March 2023, outbreaks of the H5N2 strain were detected in backyard poultry farms in Michoacán, which borders the State of Mexico. Another two cases were identified in Texcoco and Temascalapa in the same state. The WHO has not established a direct connection between these animal outbreaks and the human case.
- The presence of H5N2 in Mexico has been known since 2022, and it has also been reported in animals in other countries. The National Agri-Food Health, Safety and Quality Service (Senasica) in Mexico had declared the country free from H5N2 bird flu as of April 5, stating that the virus had not been present in commercial production since June 1995.
