Context:
Since 2020, a highly pathogenic strain of bird flu, H5N1, has been rapidly spreading across the world, presenting an existential threat to birds and wildlife. As of December 2023, the virus has been detected in birds in over 80 countries, highlighting its widespread impact. In January 2024, the Executive Director of Health at the Wildlife Conservation Society revealed that H5N1 has not only infected over 150 wild and domestic avian species worldwide but also impacted dozens of mammalian species.
Relevance:
GS II: Health
Dimensions of the Article:
- Bird Flu and H5N1: An Overview
Bird Flu and H5N1: An Overview
Bird Flu (Avian Influenza)
- Definition: Bird flu, or avian flu, is an infectious viral disease primarily affecting poultry and certain wild bird species.
- Variability: Multiple strains of the bird flu virus exist, circulating among over 100 bird species without significant harm.
Cause of Concern:
- Transmission to Poultry: Occasionally, the virus transitions from wild birds to densely populated poultry farms, where it evolves rapidly, causing severe illness and death among birds.
H5N1 Bird Flu
- H5N1 is a subtype of the influenza A virus, causing severe respiratory disease known as avian influenza in birds.
Classification:
- Influenza A viruses are categorized by subtypes based on their surface proteins.
- H5N1 refers to the hemagglutinin (H) subtype 5 and neuraminidase (N) subtype 1.
Human Transmission:
- While human cases of H5N1 are rare, the mortality rate is alarmingly high at about 60%.
- Human-to-human transmission is uncommon.
Origin and Circulation:
Origins: The current strain of H5N1 evolved from a 1996 outbreak on a goose farm in Guangdong, China.
Global Spread:
- First appeared in Europe in 2020.
- Rapidly spread to Africa and Asia.
- Reached North America by late 2021.
- Emerged in South America in fall 2022.
- Reached mainland Antarctica in February 2024.
Reasons for Large-Scale Spread:
Climate Change:
- Rising global temperatures may alter bird behavior, facilitating virus spread.
Sea Surface Temperatures:
- Warmer sea temperatures affecting marine ecosystems could indirectly impact bird health and virus transmission.
Human Infection:
Transmission:
- Humans typically contract H5N1 through close contact with infected birds or contaminated environments.
- Human-to-human transmission is rare.
Cause of Concern:
Severity:
- H5N1 infection in humans can lead to severe illness with a high mortality rate.
Potential Mutation:
- If the H5N1 virus were to mutate and become easily transmissible among humans while maintaining its virulence, it could pose a significant public health risk.
-Source: The Hindu
