Context:
Recent reports of H5N1 (subtype of avian influenza) being transmitted between mammals have raised concerns about its potential to cause a human pandemic.
Relevance:
GS II: Health
Dimensions of the Article:
- What is H5N1 Avian Influenza?
- Avian Influenza in India
- Influenza Virus Types
What is H5N1 Avian Influenza?
- Avian influenza or bird flu refers to the disease caused by infection with avian influenza Type A viruses.
- H5N1 avian influenza is a highly infectious and often deadly strain of the influenza virus that primarily affects birds, but can also infect humans.
- Virus can infect mammals from birds, a phenomenon called spillover, and rarely can spread between mammals.
- The virus is primarily found in birds such as chickens, ducks, and geese, and can be transmitted to humans who come into close contact with infected birds, either live or dead, or their secretions and excretions.
- Symptoms of H5N1 in humans are similar to those of other types of influenza, and may include fever, cough, sore throat, headache, muscle aches, and pneumonia. In severe cases, H5N1 can cause respiratory failure and death.
Transmission:
- Transmission of the virus from human to human is rare, but it is possible.
- Most cases of H5N1 infection in humans have occurred in individuals who had close contact with infected birds.
- There have been a few cases of limited human-to-human transmission, but this has not yet led to sustained human-to-human transmission.
Treatment:
- There is no specific treatment for H5N1 avian influenza, but antiviral medications such as oseltamivir and zanamivir may be used to treat the symptoms of the virus.
- A vaccine is available for use in birds, but there is no vaccine currently available for humans.
Avian Influenza in India:
- In 2019, India was declared free from the H5N1 strain of Avian Influenza, and this was reported to the World Organization for Animal Health.
- However, in December 2020 and early 2021, several outbreaks of Avian Influenza were reported in 15 states in India.
- These outbreaks involved the H5N1 and H5N8 strains of the virus.
Concern:
- The primary concern with H5N1 avian influenza is its potential to cause a global pandemic if it were to mutate and become more easily transmissible between humans.
- The virus has a high mortality rate in humans, with more than half of those infected dying from the disease.
- As such, H5N1 remains a significant public health concern and a focus of ongoing research and monitoring.
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
