Researchers Trace Evolution Of H7N9, Find Other Similar Viral Strains
“Researchers have traced the evolution of the [H7N9] avian flu currently spreading in China, and have found evidence that it developed in parallel with a similar bird flu, H7N7, which can infect mammals,” Nature reports. “Although there is no evidence that this H7N7 strain will infect humans, the authors of a study published today in Nature say that their finding reinforces the idea that H7 avian viruses are constantly mixing and exchanging genetic material — a process known as reassortment — in Asian poultry markets,” the journal writes (Mole, 8/21). However, “[l]ab tests showed H7N7 was able to cause severe pneumonia in ferrets, which are usually used as proxies for humans in flu research,” Xinhua notes (8/21).
H7N9 “evolved from migratory birds via waterfowl to poultry and into people,” Reuters notes, adding, “The study — an analysis of the evolutionary history of the H7N9 bird flu that has so far killed 44 people — identified several other H7 flu viruses circulating in birds that the researchers said ‘may pose threats beyond the current outbreak’” (Kelland, 8/21). “The current pandemic threat extends beyond the H7N9 virus,” the researchers wrote, adding, “To control H7N9 and related viruses ultimately, it is necessary to reconsider the management of LPMs (live poultry markets) in urban areas,” according to the Los Angeles Times’ “Science Now” blog (Kaplan, 8/21). In related news, Cambodia has reported 17 cases of H5N1 in humans so far this year, according to a joint statement by the WHO and Cambodian Health Ministry, another Xinhua article reports (8/21).