Influenza A (H1N1) FAQ
Foreign tourists wearing protective masks stand in the main Zocalo plaza in downtown Mexico City, Monday. (AP Photo/Enric Marti) It is a respiratory disease of pigs caused by type A strains of the influenza virus. It regularly causes high flu outbreaks in pigs but with low death rates. There are four main sub-types of the virus, but the most recent isolated influenza viruses from pigs have been H1N1 viruses.
How does it spread?
