08 Jun 2024

Avian Influenza H5N2: first confirmed human death in Mexico

The World Health Organization (WHO) has recently confirmed the first human death related to avian influenza H5N2 in Mexico. This significant development raises concerns about public health and highlights the need for vigilance.

David Corredor

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The World Health Organization (WHO) has recently confirmed the first human death related to avian influenza H5N2 in Mexico. This significant development raises concerns about public health and highlights the need for vigilance. Let’s explore the details of this case.

Details of human death case

Patient profile
- The victim was a 59-year-old man who resided in the State of Mexico.
- He had no known exposure to poultry or other animals, according to the WHO.
- The patient had underlying health conditions and had been bedridden for three weeks before developing acute symptoms.
Symptoms and hospitalization
- On April 17, the patient developed symptoms including fever, difficulty breathing, diarrhea, nausea, and general malaise.
- He was admitted to the National Institute of Respiratory Diseases Ismael Cosío Villegas (INER) in Mexico City.
- Unfortunately, he succumbed to complications related to his illness on the same day.
Investigation and contagion risk
- The WHO conducted an epidemiological investigation and tested 17 identified contacts of the patient.
- No traces of influenza were found in any of these contacts.
- The origin of transmission remains unknown, as the patient had no direct exposure to birds.
Global significance
- This case marks the first laboratory-confirmed human infection with the influenza A (H5N2) virus worldwide.
- While cases of this variant have been reported in Mexican poultry, the source of transmission to humans remains a mystery.

Differences with H5N1 avian influenza

Avian influenza is a disease caused by viruses of the Orthomyxoviridae family (H5N1, H5N3, H5N8, etc.), which usually infect wild birds and poultry, such as chickens.

One of the best known is the A virus (H5N1), first detected in China in 1996. Since then it has caused worrying outbreaks in birds around the world. And over the past few years, outbreaks have also been recorded in mammals, such as cats, lions, seals or dolphins, which revealed that the virus was mutating to adapt to new hosts.

Although avian influenza mainly affects birds, it can be transmitted to humans, especially to poultry workers or other people in contact with infected birds or contaminated surfaces. In other words, the virus does not enter the organism through the consumption of birds, but through their handling.

As for human cases, and still speaking of influenza A (H5N1), from 2003 to April 1, 2024, a total of 889 cases and 463 deaths (case fatality rate of 52%) have been reported worldwide in 23 countries.

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Low risk of contagion

The WHO emphasizes that the risk of contagion from this virus to the general population is currently low. However, any human infection caused by a new subtype of the influenza A virus warrants close monitoring.

Conclusion

As health authorities continue to investigate, it is crucial to remain vigilant and take necessary precautions. The emergence of avian influenza H5N2 in humans underscores the importance of global surveillance and rapid response to potential health threats.

Sources: Available upon request.

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