H1N1 virus is sometimes mentioned in the news with reference to which one of the following diseases?
Answer & explanation
Answer: (d) Swine flu
H1N1 is a subtype of influenza A virus. WHO's April 2009 outbreak notice described the new strain as 'Swine Influenza A/H1N1', and the disease is popularly called swine flu. The other three diseases are caused by different pathogens.
- ✓ (d) WHO's April 2009 outbreak notice described the human cases in Mexico and the USA as Swine Influenza A/H1N1. The disease is therefore known as swine flu.
- ✗ (b) Bird flu (avian influenza) is mainly linked to A(H5N1), and also to A(H7N9) and other H5 subtypes, not H1N1. This is the most tempting wrong option because both are influenza A viruses.
- ✗ (a) AIDS is caused by HIV, a retrovirus, not an influenza virus.
- ✗ (c) Dengue is spread by mosquitoes and is caused by the dengue virus, which is unrelated to influenza viruses.
Remember · H1N1 = swine flu (2009 pandemic strain). H5N1 and H7N9 = bird flu. Influenza subtypes are named by the H (haemagglutinin) and N (neuraminidase) proteins.
Sources
- WHO Disease Outbreak News, 24 April 2009: Swine influenza ↗ “The Swine Influenza A/H1N1 viruses characterized in this outbreak have not been previously detected in pigs or humans.”
- WHO Fact sheet: Influenza (avian and other zoonotic) ↗ “In 1997, human infections with A(H5N1), A/Goose/Guangdong/1/1996 (Gs/Gd/96) lineage, viruses were reported during an outbreak in poultry in the Hong Kong special Administrative Region, China.”
Question: UPSC Civil Services (Preliminary) 2015, General Studies Paper I. Explanation: Minimalist IAS, checked 25 Oct 2026 (how we verify). ·
