Researchers at the Chinese Center for Disease Control and Prevention in Beijing have offered details about three of at least nine known deaths associated with H7N9 bird flu.
In a report on the virus published online by the New England Journal of Medicine, the team described genetic and clinical characteristics of the new influenza strain, the first H7N9 known to infect humans. The viruses detected in the three patients all originated in birds, and contain genetic elements similar to known H7N9, H9N2, and H7N3 viruses.
The similarities between avian flus and the new virus may support the possibility that people catch the new H7N9 from birds and not from other people, the researchers wrote. At the same time, the team found changes in the H7N9 viral genes that have made past flus more virulent in people.
All of the victims in the three fatal cases described -- an 87-year-old man, a 27-year-old-man, and a 35-year-old woman -- suffered a high fever and cough, and as their disease progressed, they developed acute respiratory distress syndrome, in which fluid builds up in the air sacs of the lungs, preventing oxygen uptake in the body. The eldest H7N9 patient died after 13 days; the other two patients, after only about a week. All three received antiviral medications about a week after they fell ill.