HARBIN, China, April 28 (UPI) -- Scientists searching for the source of the H7N9 influenza virus causing human infections in China said it appeared to originate in Shanghai poultry markets.
Professor Chen Hualan and colleagues at the National Avian Influenza Reference Laboratory, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute and Chinese Academy of Agricultural Sciences investigated the origins of the novel H7N9 influenza virus.
A total of 970 samples were collected from live poultry markets and poultry farms located in Shanghai and Anhui Province. Samples analyzed included drinking water, feces, contaminated soil and other swabs, Hualan said.
Of these samples, 20 were positive for the presence of H7N9 influenza viruses -- all of the positive samples originated from live poultry markets in Shanghai. Of these 20 positive samples, 10 were isolated from chickens, three from pigeons and seven were from environmental samples.
The complete genome of three H7N9 isolates, from a chicken, pigeon and environmental sample, was sequenced and deposited into the GISAIDdatabase.
Genetic analysis of these isolates revealed high homology -- the same organ in different animals -- across all eight gene segments. Analysis of these novel H7N9 influenza virus isolates showed that that the six internal genes were derived from avian H9N2 viruses, but the ancestor of their HA and NA genes was unknown, Hualan said.
The findings were published in the Chinese Science Bulletin.