An international team of researchers reported in the journal Nature that the H7N9 influenza virus's genetic diversity is increasing in poultry populations in China. Since 2013, 571 cases have been reported in humans as of February, according to the World Health Organization.
Scientists Ron Fouchier and Ab Osterhaus are manipulating the genome of the H7N9 avian influenza virus in an effort to create a strain that is easily transmissible among humans. They say developing such a strain would be a major advancement in learning how to prevent and treat the already deadly influenza virus, which has killed 45 of the 136 people who have been infected. However, opponents think the work is risky. Steven Salzberg, a professor at the Johns Hopkins University School of Medicine, said, "The notion of 'gain of function' research on pathogens is very, very dangerous."
H7N9, the avian influenza virus that has infected some 133 people in China since March, killing 43 of them, has the potential to cause serious illness and even a pandemic, according to newly published research by University of Wisconsin-Madison researcher Yoshihiro Kawaoka, the same scientist who rendered H5N1 transmissible among ferrets, sparking global controversy. Kawaoka identified factors that make H7N9 a serious public health threat: It can cause infection in the lower respiratory tract in addition to the upper respiratory tract; one sample was transmitted via air between ferrets; and infected chickens usually don't suffer serious health problems.
The U.S. government, in recognition of the possible threat presented by H7N9 bird flu, has authorized the emergency use of unapproved diagnostic kits that can detect flu genes using a polymerase chain reaction test. The move is intended to hasten the delivery of antiviral drugs and limit the transmission of the virus while vaccines are developed. The next emergency authorization may be for adjuvants, immune-stimulating chemicals that would be put in vaccines.
The CDC has received the first H7N9 virus isolate from China for use in continuing preparedness measures, including the development of a vaccine and a serologic assay. The CDC also will use the isolate to assess the agency's diagnostic test kit. The agency will grow the virus and share it with appropriate laboratories.