Three Human Cases of Avian Influenza A (H7N9) Reported in China

Photo credit: Dr. Gonzalo Bearman

Here is an alert from the World Health Organization on 3 H7N9 avian influenza cases ("bird flu") discovered in China. Two cases were reported in Shanghai with another case reported in Anhui province. Patients presented with respiratory infections that progressed to severe pneumonia between February and March 2013; 2 of these patients have died.

Investigation into these cases is ongoing; to date, there has been no evidence that person to person transmission has occurred.

Avian influenza A viruses do not typically infect people, although cases have been reported. When human infection occurs, it is usually in people who have been in close proximity to infected poultry. To date, human to human transmission of avian influenza has been rare.

There is always concern with influenza that viruses circulating in animals (such as birds) will "jump" to humans, combine with human strains and create new influenza strains that we, collectively, have little or no immunity to. This phenomenon led to the 1918-1919 global influenza pandemic that killed between 20 and 40 million people. This is why we must continue to be vigilant in monitoring for cases of human infection with animal influenza strains, such as H7N9 avian influenza.