H3N2

Flu

Flu Flu vaccine Avian flu H5N1 flu Phylogenetics

H3N2 is a subtype of the species avian influenza virus (bird flu virus). H3N2 has mutated into various strains including the Hong Kong Flu strain (now extinct) and the annual flu.

The annual flu (also called "seasonal flu" or "human flu") kills an estimated 36,000 people in the United States each year. The annual flu vaccine is made by combining vaccines for the new versions of H1N1 and H3N2 viruses that nature produces each year. The dominant strain of annual flu in January 2006 is H3N2. Measured resistance to the standard antiviral drugs amantadine and rimantadine in H3N2 has increased from 1% in 1994 to 12% in 2003 to 91% in 2005. ^[1] "[C]ontemporary human H3N2 influenza viruses are now endemic in pigs in southern China and can reassort with avian H5N1 viruses in this intermediate host." ^[2]

Hong Kong Flu

The Hong Kong Flu strain of H3N2 evolved from H2N2 by antigenic shift and caused the Hong Kong Flu pandemic of 1968 and 1969 that killed up to 750,000. ^[3] "An early-onset, severe form of influenza A (H3N2) made headlines when it claimed the lives of several children in the United States in late 2003." ^[4]

The Hong Kong Flu was a pandemic outbreak of influenza that began in Hong Kong in 1968 and spread to the United States of America that year. The outbreak ended the following year, in 1969.

The Hong Kong flu was the A type of influenza, specifically the first known outbreak of the H3N2 strain (a notation that refers to the configuration of the hemagglutinin and neuraminidase proteins in the virus).

Because of its similarity to the 1957 Asian Flu (which was the H2N2 strain, differing from the Hong Kong flu only in the chemical arrangement of the hemagglutinin protein as a result of antigenic shift) and possibly the subsequent accumulation of related antibodies in the affected population, the Hong Kong flu resulted in much fewer casualties than most pandemics. Casualty estimates vary: between 750,000 and two million people died of the virus worldwide (34,000 people in the United States) during the two years (1968-1969) that it was active. It was therefore the least lethal pandemic in the 20th century.

Further reading

• Graphic showing H3N2 mutations, amino acid by amino acid, among 207 isolates completely sequenced by the Influenza Genome Sequencing Project.
• Influenza A (H3N2) Outbreak, Nepal
• Hot topic - Fujian-like strain A influenza
• Monitoring Antibodies for Swine Influenza H3N2 Virus
• Human influenza A(H3N2) activity remains widespread in many countries - update 7
• Human influenza A/H3N2 activity increases in many countries in central and eastern Europe - update 8
• Influenza A H3N2

Sources

1. ↑ Reason New York Times
2. ↑ NAP online book
3. ↑ (Detailed chart of its evolution here.)
4. ↑ NAP online book

New Scientist: Bird Flu

The content of this page is retrieved from http://en.wikipedia.org/wiki/Hong_Kong_Flu under GFDL