Influenza A virus subtype H1N1

Influenza A virus subtype H1N1 (A/H1N1) is a type of influenza A virus (IAV). Some human-adapted strains of H1N1 are endemic in humans and are one cause of seasonal influenza (flu). 

Other strains of H1N1 are endemic in pigs (swine influenza) and in birds (avian influenza). 

Types of IAV are a combination of the antigenic H and N proteins in the viral envelope.

Major outbreaks of H1N1 strains in humans include the 1918 Spanish flu pandemic, the 1977 Russian flu pandemic and the 2009 swine flu pandemic, all of which were caused by strains of A(H1N1) virus which had genetic reassortment.

References

Category:Pulmonology
A virus subtype H1N1