Chickens and ducks aren’t getting sick from a new strain of bird flu this flu season, but they’re giving it to people and some have died. People have killed infected birds to prevent its spread, but the virus still lurks. The new avian-flu variant killed 45 in China in the spring of 2013, provoking fear of a global contagion if it mutates. Live-bird markets were temporarily closed and farms were quarantined in response. That stopped human cases for two months. Two infections in October showed the virus circulating. Now a domestic helper living in Hong Kong has the disease, probably as a result of buying and slaughtering a chicken she bought in the neighboring Chinese city of Shenzhen. Scientists worry that poultry fattened for Chinese New Year feasts could spread avian influenza.
Since February, 137 cases of H7N9 avian flu have been reported to the World Health Organization, most of them in eastern China in April. Some patients are still hospitalized after catching the germ, which can cause suffocation and organ failure. H7N9 isn’t nearly as infectious as the H1N1 swine flu strain that set off the 2009 influenza pandemic, the first in 41 years, but it appears to be a lot more deadly. Precisely how people get infected isn’t known, but poultry are implicated because most people are affected after exposure to fowl or to environments that might be contaminated with bird flu virus, like markets. There’s no evidence of sustained human-to-human spread. Dozens of farm workers have antibodies against H7N9, suggesting many were infected without getting sick.