Update on Human H7N9 Avian Influenza Cases in China

VCU Global Health & Health Disparities Program (GH2DP)
group entering Honduras during the H1N1 pandemic, 2009

Here is the latest update from the WHO on human H7N9 avian influenza cases in China; as of April 5 16 patients have laboratory-confirmed infection (up from just 3 a few days ago) and 6 have died. Contacts of the people who are infected are being closely watched for signs and symptoms of respiratory infection; to date no clear evidence of person to person transmission has been found.

Although it not clear yet where people acquired H7N9, the virus has been detected in pigeons in a major Chinese agricultural market, leading to the mass execution of 20,000 birds.

Here is an April 4th health advisory on H7N9 from the CDC and an April 5 'telebriefing' with the CDC's director Dr. Tom Frieden. Here is detailed, specific travel advice from the CDC for people going to China (emphasizing such things as avoiding live bird and poultry markets, practicing good hand hygiene, et cetera).

Much is unknown about the epidemiology and transmissibility of the H7N9 virus; to date it does not look efficient in terms of person to person transmission, which is the public health community's greatest concern. One thing is certain: these new human cases of "bird flu" illustrate how quickly novel infectious disease threats can emerge, and we must be vigilant and act quickly as a global community to identify, contain and development treatments for these diseases when they appear.

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.