Six deaths announced in the past six days from a new strain of bird flu in China has led authorities to kill all of the pigeons being sold for meat at a Shanghai market.
The virus, H7N9, has infected at least 14 people so far, most likely through direct contact with birds. No person-to-person transmission has been detected, but health officials and scientists are closely monitoring the virus for similarities to past outbreaks.
This particular strain may be trickier to detect because it can infect birds without any noticeable effect on their health, The Associated Press reports.
“In the past usually you would see chickens dying before any infections occurred in humans, but this time we’ve seen that many species of poultry actually have no apparent problems, so that makes it difficult because you lose this natural warning sign,” David Hui, an infectious diseases expert at the Chinese University of Hong Kong, told The Associated Press.
The virus may have undergone a recent mutation that makes it easier to pass on to other animals, scientists have said. Health officials put those who work closely with birds on alert. Some of the 14 people infected were sicked weeks ago, but weren’t diagnosed with H7N9 until recently.
Although pigeons have been identified as the carriers so far, it’s likely that other types of poultry are also carrying the virus, Hui said.