WHO: H7N9 bird flu in China appears under control

Chickens are sold at a market in Shanghai, China on Thursday, April 4, 2013. (AP)

The outbreak in China of a new strain of bird flu, called H7N9, appears to have been brought under control, World Health Organization experts said Tuesday.

Chinese authorities told reporters gathered for the WHO’s annual World Health Assembly that it appears that stringent restrictions at open-air bird markets helped rein in the outbreak.

But the virus, which has killed 36 people, has not disappeared, and health authorities around the world must remain on the lookout for new infections, the experts said.

Bernard Vallat, head of the United Nations’ OIE (World Organisation for Animal Health), told reporters there have been no human cases of the virus since May 8.

“That is a good indication and means measures are being taken seriously," he said. “Now when the virus is found at market, all birds are killed. That is important too.”

Still, Keiji Fukuda, WHO assistant director-general for health security, noted that flu viruses don’t spread as easily in the summer as they do in the winter and health authorities cannot yet lower their guard.

"The immediate outbreak has been controlled, but it is also unlikely that the virus has simply disappeared. We believe we need go another autumn/winter/spring season to know," he told the reporters.

Most of the 130 Chinese who became infected with H7N9 picked up the virus from birds, but Fukuda warned there is still a possibility the virus could develop the ability to spread easily from person to person, which would likely cause a widespread influenza pandemic.

"We also have high concern over the potential -- I stress, the ‘potential’ -- to gain the ability to sustain transmissibility," he said

China’s Health Minister Li Bin said the outbreak showed no evidence of sustained human-to-human transmission and lab tests suggest there has been no genetic mutation of the virus that would give it the ability to spread easily from person to person.

She also said her country’s experience showed it’s possible to control H7N9.

Li said local Chinese authorities were able to shut down live poultry markets "temporarily or permanently” in 10 provinces, which brought outbreaks under control. The country also enacted standards regarding the transportation of poultry, which reduced spread among birds.

Also Tuesday, the chief veterinary officer at the UN's Food and Agriculture Organization, Juan Lubroth, said the "economic impacts of H7N9 have been astounding.”

He said China's agriculture ministry estimates that over US$6.5 billion was lost in the country’s agriculture sector because the outbreak.

Since emerging in March, H7N9 infected 130 people in mainland China. Of those, 36 died, 35 patients remain in hospital, and the rest have since recovered and been discharged.

One infection was also discovered in Taiwan, for a total of 131 cases. That patient appeared to contract the virus while visiting China.

Most of those infected appeared to pick up the virus at live poultry markets, particularly through infected ducks and chickens, lab tests revealed.

Fukuda told reporters back in April that humans seem to catch H7N9 from birds relatively easily – more easily than they contract H5N1 bird flu, the strain that started killing people a decade ago.