By Kate Kelland
LONDON – Chinese scientists have confirmed for the first time that a new strain of bird flu that has killed 23 people in China has been transmitted to humans from chickens.
In a study published online in the Lancet medical journal, the scientists echoed previous statements from the World Health Organization (WHO) and Chinese officials that there is as yet no evidence of human-to-human transmission of this virus.
The H7N9 strain has infected 109 people in China since it was first detected in March. The WHO warned on Wednesday that this strain is “one of the most lethal” flu viruses and is transmitted more easily than the H5N1 strain of bird flu, which has killed hundreds around the world since 2003.
Kwok-Yung Yuen of the University of Hong Kong, who led the study, said its findings that chickens in poultry markets were a source of human infections meant that controlling the disease in these places and in these birds should be a priority.
“Aggressive intervention to block further animal-to-person transmission in live poultry markets, as has previously been done in Hong Kong, should be considered,” he told the Lancet.
He added that temporary closure of live bird markets and comprehensive programmes of surveillance, culling, biosecurity and segregation of different poultry species may also be needed “to halt evolution of the virus into a pandemic agent”.
“The evidence … suggests it is a pure poultry-to-human transmission and that controlling (infections in people) will therefore depend on controlling the epidemic in poultry,” he said.
Yuen’s findings do not mean all cases of human H7N9 infection come from chickens, or from poultry, but they do confirm chickens as one source.
The WHO has said 40 percent of people infected with H7N9 appear to have had no contact with poultry.
Other so called “reservoirs” of the flu virus may be circulating in other types of birds or mammals, and investigators in China are working hard to try find out.
Source: Poultry Science Association