TAG: GS 3: SCIENCE AND TECHNOLOGY
THE CONTEXT: The World Health Organization (WHO) has confirmed the first-ever human death caused by the H5N2 strain of avian influenza.
EXPLANATION:
- This case marks a significant development in the understanding and monitoring of avian influenza’s impact on human health.
- The victim was a 59-year-old resident of the State of Mexico with underlying health conditions.
- The individual, who had no known history of exposure to poultry or other animals, was hospitalized in Mexico City on April 24, 2024.
- The patient exhibited symptoms such as fever, shortness of breath, diarrhea, nausea, and general discomfort.
- Despite medical intervention, the patient passed away in April. Laboratory tests confirmed that the cause of death was due to the H5N2 virus.
Public Health Response
- The WHO and Mexican health authorities are treating this case with high priority due to its potential public health implications under the International Health Regulations (IHR), 2005.
- Despite this, WHO has assessed that the virus poses a low risk to the general population.
- Health officials have identified and tested 17 close contacts of the deceased.
- Among these, one individual reported a runny nose between April 28 and 29, but tests for influenza and SARS-CoV-2 were negative.
- Additionally, twelve other contacts (seven symptomatic and five asymptomatic) from the patient’s vicinity were tested, all of which returned negative results for influenza A, B, and SARS-CoV-2.
- The results of serology or blood serum tests are still pending.
Outbreaks in Poultry
- Prior to this human case, there were multiple outbreaks of the H5N2 strain in poultry within Mexico:
- March 2024: An outbreak in a backyard poultry farm in Michoacán, which borders the State of Mexico.
- Late March 2024: An outbreak in Texcoco, State of Mexico.
- April 2024: Another outbreak in Temascalapa, State of Mexico.
- Authorities have not been able to link the human case directly to these poultry outbreaks.
Background of Avian Influenza in the Region
- In addition to the H5N2 strain, Mexico has experienced other avian influenza outbreaks:
- March 2024: The H5N1 strain was found in dairy cattle across nine states, leading to some human infections among those who had close contact with the animals.
- May 2024: Australia reported its first human infection with the H5N1 strain, with no evidence of human-to-human transmission.
- 2021: An outbreak of the H5N6 strain led to the deaths of 18 herons in China, according to the United States Centers for Disease Control and Prevention (CDC).
H5N2 Bird flu:
- H5N2 is a subtype of the Avian Influenza A virus.
- Influenza A viruses are categorised by subtypes based on the proteins on their surfaces.
- There are 18 different hemagglutinin (H) and 11 different neuraminidase (N) subtypes, including H5N2.
- Hemagglutinin is a glycoprotein found on the surface of influenza viruses and neuraminidase is an enzyme found on the surface of the viruses that enable them to be released from the host cell.
- H5N2 has been first reported in poultry in Mexico.
