About Bird Flu (Avian Influenza)

Context:

The recent surge in bird flu outbreaks among mammals has alarmed international agencies, including the Food and Agriculture Organization (FAO), the World Health Organization (WHO), and the World Organisation for Animal Health(WOAH, founded as OIE).

Relevance:

GS II: Health

Dimensions of the Article:

1. Bird Flu (Avian Influenza)
2. Status of Bird Flu in India
3. Influenza Virus Types

Bird Flu (Avian Influenza)

• Bird flu, also known as Avian influenza, is a disease caused by infection with avian influenza Type A viruses.
• It primarily affects birds but can occasionally infect mammals through spillover.
• The most common type of bird flu virus is H5N1, which emerged in 1996/1997 and has caused significant outbreaks since then.

Bird Flu Outbreaks

• Since 2020, H5N1 avian influenza outbreaks have been reported in numerous countries across Africa, Asia, Europe, and the Americas
• These outbreaks have resulted in the death or culling of over 131 million domestic poultry in affected farms and villages. In 2023, additional outbreaks have been reported in 14 countries.

Spillover to Mammals

• In recent years, cases of avian flu in mammals have been observed in approximately 10 countries.
• Mammals affected include farmed mink, seals, sea lions, and cats.
• There is concern that infected mammals could serve as hosts for the mixing of influenza viruses, potentially leading to the emergence of new, more harmful viruses.

Risk to Humans

• While bird flu primarily affects birds and mammals, there have been only a few mild cases reported in humans who had close contact with infected birds.
• The World Health Organization (WHO) closely monitors these cases to assess the risk to human health.

Status of Bird Flu in India

• On September 3, 2019, the World Organization for Animal Health declared India free from Avian Influenza (H5N1).
• However, outbreaks of avian influenza H5N1 and H5N8 were reported in poultry in 15 states in India in December 2020 and early 2021.

Measures to Control Spread

To address the risks associated with bird flu outbreaks, international agencies such as FAO, WHO, and WOAH recommended the following measures:

• Sharing Genetic Data: Countries were urged to share genetic data of viruses from humans and animals in publicly accessible databases.
• Enhancing Biosecurity and Hygiene: Implementation of biosecurity measures and good hygiene practices in farms and poultry value chains.
• Rapid Detection and Response: Ensuring prompt detection, reporting, and response to animal outbreaks to prevent further spread.
• Strengthening Surveillance: Enhancing influenza surveillance in both animals and humans to monitor and track the disease.
• Thorough Investigations: Conducting comprehensive epidemiological and virological investigations around animal outbreaks and human infections.
• Collaboration: Promoting collaboration and coordination between the animal and human health sectors to effectively manage the disease.

Influenza Virus Types

• The influenza virus can be classified into four types, namely influenza A, B, C, and D.
• Influenza A and B are the two types that cause epidemic seasonal infections every year.
• Influenza C primarily occurs in humans, but it has also been reported in dogs and pigs.
• Influenza D is mainly found in cattle and is not known to cause illness in humans.

Avian Influenza Type A Viruses

• The type A influenza viruses are classified based on two proteins on their surface, namely Hemagglutinin (HA) and Neuraminidase (NA).
• There are around 18 subtypes of HA and 11 subtypes of NA.
• Several combinations of these two proteins are possible, such as H5N1, H7N2, H9N6, H17N10, H18N11, etc.
• All subtypes of influenza A viruses can infect birds, except subtypes H17N10 and H18N11, which have only been found in bats.

-Source: The Hindu