What is influenza A(H1N1)?

How do people become infected with influenza A(H1N1)?

Outbreaks in humans are now occurring from human-to-human transmission. When infected people cough or sneeze, infected droplets get on their hands, drop onto surfaces, or are dispersed into the air. Another person can breathe in contaminated air, or touch infected hands or surfaces, and be exposed. To prevent spread, people should cover their mouth and nose with a tissue when coughing, and wash their hands regularly.

What are the signs and symptoms of infection?

Early signs of influenza A(H1N1) are flu-like, including fever, cough, headache, muscle and joint pain, sore throat and runny nose, and sometimes vomiting or diarrhoea.

Why are we so worried about this pandemic possibility when thousands die every year from seasonal epidemics?

Seasonal epidemics occur every year and we are able to treat the virus with seasonal vaccines. A pandemic is a worldwide epidemic. It is a new virus and one to which the populations will have no immunity.

The 2009 swine flu outbreak in humans is due to a new strain of influenza A virus subtype H1N1 that contains genes closely related to swine influenza. The origin of this new strain is unknown. However, the World Organization for Animal Health (OIE) reports that this strain has not been isolated in pigs. This strain can be transmitted from human to human, and causes the normal symptoms of influenza.

Pigs can become infected with human influenza, and this appears to have happened during the 1918 flu pandemic and the 2009 swine flu outbreak.