Context:
Article in The Hindu about the story of recreation of H1N1 influenza virus which cased the deadliest pandemic (Spanish Flu of 1918) in history
About Spanish Flu (1918):
- The 1918 influenza pandemic was the most severe pandemic in recent history.
- Causative agent: H1N1 virus with genes of avian origin.
- 500 million people or 1/3rd of the world’s population became infected
- Estimated deaths: at least 50 million worldwide (for comparison, WHO estimate of Covid-19 deaths till August 2023 is around 7 million)
- High mortality in healthy people, including those in the 20-40 year age group, was a unique feature of this pandemic.
About the news:
- Researchers successfully reconstructed the influenza virus that caused the 1918-19 flu pandemic in 2005 –
- it provided new information about the properties that contributed to its exceptional virulence.
- helped health officials to devise appropriate strategies for early diagnosis, treatment, and prevention, should a similar pandemic virus emerge.
- informs the development of general principles with which we can better design antiviral drugs and other interventions against all influenza viruses with enhanced virulence.
- Are current antivirals and vaccines effective against the 1918 H1N1 virus?
- There are vaccines which are effective against similar influenza A(H1N1) viruses and is expected to be effective against the 1918 H1N1 virus.
Influenza viruses are almost always circulating among humans. The nature of the virus means that every year, the virus’s genetic material undergoes some minor changes, rendering it a little different from the virus of the previous year. So scientists have to guess which changes are likely to survive the next year, and design or update their vaccines accordingly.
About H and N in influenza virus:
- Researchers designate influenza strains using the types of two genes that the virus contains – haemagglutinin (H) and neuraminidase (N).
- There are 18 subtypes of haemagglutinin, labelled H1-H18, and 11 types of neuraminidase, N1-N11, in nature. An influenza virus contains one of each and is classified accordingly.
- 1918 Spanish flu – H1N1
- 1957 Asian flu – H2N2
- 1968 Hong Kong flu – H3N2
The 1918 Spanish flu and the 2009 swine flu were both caused by H1N1 – but they varied in disease severity due to the presence of changes on the H1 and N1 genes.
Source: The Hindu – 1, 2
Previous year question
H1N1 virus is sometimes mentioned in the news with reference to which one of the following diseases?
[UPSC Civil Services Exam – 2015 Prelims]
(a) AIDS
(b) Bird flu
(c) Dengue
(d) Swine flu
