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H5N1

21st February, 2024

H5N1

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Picture Courtesy: https://www.walesonline.co.uk/news/uk-news/unprecedented-bird-flu-outbreak-leads-24896156

Context: A bird flu outbreak caused by the H5N1 variant of the avian influenza virus was reported in Andhra Pradesh’s Nellore district.

Details

  • In response to the outbreak, hundreds of birds and eggs were culled. Restrictions were imposed, including a three-day ban on chicken sales within a 10-kilometer radius of the epicentre and a three-month ban within a 1-km radius.
  • Officials believe migratory birds in Pulicat Lake in nearby Tirupati district likely transmitted the virus to poultry. Migratory wild aquatic birds, particularly waterfowl, are known natural reservoirs for influenza A viruses.
  • A recent study in the journal Emerging Infectious Diseases highlighted the avian influenza A virus subtype H5N1's panzootic phase between 2020 and 2023, affecting various mammal species. The virus originally infected birds in 2003 and has since crossed over to numerous mammal species.
  • The study underscored the risk of mammalian adaptation and its potential impact on human health. Since 2020, the virus has infected over 48 mammal species, raising conservation concerns.
  • While there is currently no evidence of human-to-human transmission, mutations in the H5N1 virus could increase the risk of a pandemic. The report highlights specific mutations found in minks and wild and domestic pigs that should be closely monitored due to potential risks to human health.

About H5N1

Type

Subtype of the Influenza A virus

Cause

Highly pathogenic avian influenza (HPAI)

Affected Species

Primarily birds (wild and domestic), but can also infect mammals and humans

Transmission

Primarily through direct contact with infected birds or their secretions; limited human-to-human transmission

Symptoms in Birds

Sudden death, respiratory distress, lack of appetite, neurological signs

Symptoms in Humans

Fever, cough, sore throat, muscle aches, diarrhoea, pneumonia, neurological changes

Mortality Rate

High in birds (up to 100%), around 60% in humans

Current Global Situation

Widespread in wild birds, sporadic outbreaks in poultry, rare human cases

Public Health Risk

Currently considered low, but continuous surveillance is crucial due to the potential for mutation

Prevention in Birds

Biosecurity measures, vaccination programs, culling of infected flocks

Prevention in Humans

Avoid close contact with infected birds, wear protective gear when handling poultry, practice good hygiene

Treatment in Humans

Antiviral medications, supportive care

Vaccine

Vaccines are used to protect poultry flocks, but no licensed vaccine for humans exists yet

Future Concerns

Potential for mutation or reassortment leading to increased human-to-human transmission

Must Read Articles:

BIRD FLU: https://www.iasgyan.in/daily-current-affairs/bird-flu-30

PRACTICE QUESTION

Q. One-Health is an important approach to managing H5N1. What aspect of One-Health is NOT directly relevant to H5N1 control?

A) Understanding the ecological factors influencing virus transmission in birds.

B) Strengthening veterinary and human public health systems globally.

C) Promoting responsible antibiotic use in animal agriculture.

D) Developing effective vaccines and treatments for both humans and animals.

Answer:  

Explanation:

One-Health is an approach that recognizes the interconnectedness of human, animal, and environmental health, aiming to address health issues holistically. While responsible antibiotic use in animal agriculture is certainly important for addressing antibiotic resistance and overall public health, it is not directly related to controlling the transmission and spread of the H5N1 avian influenza virus.

Understanding the ecological factors influencing virus transmission in birds (option A), strengthening veterinary and human public health systems globally (option B), and developing effective vaccines and treatments for both humans and animals (option D) are all directly relevant to controlling H5N1 as they focus on understanding the virus, improving surveillance and response capabilities, and developing preventive measures such as vaccines and treatments.