Why in news?

Three tigers and a leopard at a Nagpur rescue center have died from avian influenza (H5N1), a rare instance of the virus affecting rescued wildlife in India.

In response, the Union government has issued an advisory, urging zoos nationwide to remain vigilant, follow the action plan for prevention and containment, and monitor for symptoms in captive animals or nearby areas. The advisory highlights the highly contagious and zoonotic nature of the disease.

What’s in today’s article?

• H5N1
• Zoos put on alert

Avian influenza (H5N1)

• Overview of Bird Flu
  • Bird flu, or avian flu, is an infectious viral illness primarily affecting poultry and wild birds.
  • Various strains of the virus have circulated among at least 100 bird species, with wild waterfowl like ducks and geese often serving as carriers without severe harm.
• About
  • H5N1 is a type of influenza virus that causes a highly infectious, severe respiratory disease in birds called avian influenza (or "bird flu").
  • Basically, it is a subtype of the influenza A virus.
    • Influenza A viruses are classified by subtypes based on the properties of their surface proteins.
  • Human cases of H5N1 avian influenza occur occasionally, but it is difficult to transmit the infection from person to person.
    • When people become infected, the mortality rate is about 60%.
• Evolution and Global Spread of H5N1
• The highly pathogenic H5N1 virus originated from a goose farm outbreak in Guangdong, China, in 1996.
• A new version of the virus emerged in Europe in 2020 and rapidly spread to Africa, Asia, North America (2021), South America (2022), and mainland Antarctica (2024), causing widespread illness and death among birds.
• Impact on Farm and Wild Birds
  • Farm Birds: H5N1 spreads quickly in overcrowded poultry farms, leading to significant outbreaks and fatalities.
  • Wild Birds: The virus has caused severe mortality among wild bird populations, including:
    • Great Skuas in Scotland (2021)
    • Barnacle Geese in Solway Firth (2021/22)
    • Thousands of ducks, swans, gulls, and birds of prey like Peregrine Falcons and Golden Eagles across Europe.
  • Endangered species like the California condor have been significantly affected, with 21 deaths reported in 2023, constituting nearly 6% of the population.
• Spread Among Mammals
  • H5N1 has begun infecting mammals, raising concerns about viral reassortment and increased virulence:
    • Terrestrial Mammals: Cases reported among foxes, pumas, skunks, and bears in North America.
    • Farmed Mammals: Minks in Spain and Finland have been infected, increasing the risk of cross-species transmission.
    • Marine Mammals: Massive die-offs have been observed, including:
    • Over 20,000 sea lions in Chile and Peru.
    • Thousands of seals in the US.
  • 95% mortality among Southern elephant seal pups along the Patagonia coastline (2023), marking the first major elephant seal mortality in half a century.
• Human Risk
  • Although humans rarely contract bird flu, infections typically occur through contact with sick birds at poultry farms, where viral loads are high.

Zoos put on alert

• India's First Case of Avian Influenza in Animals
  • Maharashtra reported India's first case of avian influenza (H5N1) among animals.
    • Three tigers and one leopard have succumbed to the virus at a Nagpur rescue center in late December 2024.
  • This marks the first instance of bird flu crossing the species barrier in India.
• Government Response and Guidelines
  • The Union Animal Husbandry Ministry issued a circular urging all States to quarantine infected or symptomatic tigers and other feline species to prevent transmission to humans and other animals.
  • The ministry plans to release detailed guidelines within a week.
• Investigation and Containment Efforts
  • Post-mortem samples from the affected animals tested positive for avian influenza at the National Institute of High Security Animal Diseases (NIHSAD), Bhopal.
    • Authorities suspect contaminated chicken meat could be the source of the infection.
  • A National Joint Outbreak Response Team has been deployed to implement containment measures, while human contacts are being screened as a precaution.
• Enhanced Biosecurity Protocols
  • The Ministry directed:
    • Temporary closure of affected establishments to the public.
    • Strengthening biosecurity measures and restricting personnel movement between infected and healthy areas.
    • Thorough disinfection of affected areas and collection of samples for strain identification.
• Protection for Zoo Staff
• Zoo staff are required to use personal protective equipment (PPE), including gloves, masks, and suits.
• Regular health screenings and hygiene education for zoo personnel have also been mandated.
• Call for a One-Health Approach
  • The Ministry emphasized a "One-Health" approach, integrating efforts across human health, animal health, and wildlife sectors to comprehensively address the issue.
  • Immediate attention is needed to mitigate risks to both animal and human health.