Hard to detect, China bird flu virus may be more widespread

Bird flu infection rates on Chinese poultry farms may be far higher than previously thought, because the strain of the deadly virus that has killed more than 100 people this winter is hard to detect in chickens and geese, animal health experts say. Poultry that have contracted the H7N9 strain of the avian flu virus show little or no sign of symptoms. That means any infection is only likely to be detected if farmers or health authorities carry out random tests on a flock, the experts said. But in humans, it can be deadly. That’s different to other strains, such as the highly pathogenic H5N6 that struck South Korean farms in December, prompting the government to call in the army to help cull some 26 million birds. But that strain didn’t kill any people. There have been multiple outbreaks of bird flu around the world in recent months, with at least half a...