Update as of 26 April 2013
Note that this document supersedes the previous version. Updates will be posted as new information becomes available.
1. What is the avian influ...
4. Why is this virus infecting humans now?
We do not know the answer to this question yet, because we do not know the source of exposure for these human infections. However, analysis of the genes of these viruses suggests that although the viruses have evolved in birds, they may infect mammals more easily than other avian viruses.
7. How are people becoming infected with the avian influenza A(H7N9) virus?
At this point it is not known how persons are becoming infected. Some of the confirmed cases had contact with animals or with environments where animals are housed. The virus has now been found in chickens, ducks, and captive-bred pigeons at live bird markets near locations where cases have been reported. The possibility of an animal source of the infection is being investigated, as is the possibility of person-to-person transmission.
12. Is the source of infection poultry and live poultry markets?
Although some evidence points to live poultry as a source of infection, it cannot yet be confirmed that live poultry is the primary or the only source of infection. Neither is there enough evidence to exclude other possible animal or environmental sources of infection.
16. Is the general population at risk from the avian influenza A(H7N9) virus?
We do not yet know enough about these infections to determine whether there is a significant risk of community person to person spread. This possibility is the subject of epidemiological investigations that are now taking place.
19. Does this influenza virus pose a pandemic threat?
An animal influenza virus that develops the ability to infect people could theoretically carry a risk of causing a pandemic. However, whether the avian influenza A(H7N9) virus could actually cause a pandemic is unknown. Other animal influenza viruses that have been found to infect people occasionally have not gone on to cause a pandemic...
