Severe Illness from a Novel Avian Influenza Virus in China

In the past two decades, influenza A viruses carrying avian virus genes have shown the ability to spread directly to humans, without swine or other mammal intermediaries. Morbidity and mortality among individuals infected with these viruses have often been very high, and in some instances, person-to person spread seems to have occurred.

As of May 8, 2013, China has reported 131 confirmed influenza A (H7N9) infections and 32 deaths in humans from 10 provinces/municipalities. Nearly all cases have been sporadic, with no epidemiologic link to one another. For the 82 patients with information available, 77% had exposure to live poultry; however, at least three family clusters — each involving two or three confirmed cases — might have involved hu…