WHO warns of H7N9 pandemic

This is because H7N9 is unique as it does not make chickens sick but is deadly in humans. Sick birds could usually provide early warning for imminent outbreaks, Chan told The Standard.

This comes as Macau reported its first human case of H7N9 yesterday.

"The biggest challenge for the world is the next influenza pandemic," Chan said.

The last flu pandemic was the human swine flu H1N1 which originated in Mexico in 2009, but was considered milder than most pandemics.

Chan, who was the first to notify the WHO of a new bird flu H5N1 when she was Hong Kong's director of health in 1997, said that of the various bird flu viruses, she has paid attention the most to H7N9.

"H7N9 is unique as compared to H5N1. Why? Because when it affects the poultry population, it does not kill the bird. So we lost one early warning signal. We only see human morbidity and mortality," she said.

"In other words this is not causing disease in birds, it is only causing disease when it jumps to humans. So we need to watch it. We have been blindsided (by H7N9) as we don't have early warning signs in animals as we do in H5N1."

Chan said the world could not get complacent with flu as the viruses are "highly unpredictable and always full of surprises, starting from H5N1, H1N1 to H7N9, H5N6."

The H7N9 victim, a 58-year-old stall owner at Sociedade do Mercado Abastecedor de Macau Nam Yue, a wholesale poultry market in Macau, has not shown symptoms but has been quarantined along with his wife at Centro Hospitalar Conde de Sao Januario.

Macau has culled 10,000 live poultry and the wholesale market has been closed for sterilization. A three- day ban was imposed on live poultry trade.

This followed the discovery of H7N9 in the batch of 500 samples taken from imported silky fowls from the mainland on Tuesday.

Investigation by the Health Bureau of Macao said the man handled the cages containing the infected chickens.

He was sent to hospital and his test results came back positive for H7N9 at night.

The male truck driver who delivered the batch of chicken had returned to the mainland and Macau health officials said they have notified mainland counterparts.

"At this point in time, we see a wide spread of these viruses in both northern and southern countries in different continents," Chan said. "They are still primarily affecting the bird population.

"It has not gained sustained human- to-human transmission. We still see sporadic human cases due to close contact with poultry," Chan said.

On Tuesday, Hong Kong's Centre for Health Protection said five men in the mainland were in serious condition from H7N9.

One man, 59, is from Fujian while the four others are from Jiangsu, aged 32 to 64. All have poultry market exposure.

A spokesman for the center said bird flu virus activity increases in winter in the mainland.

"The public should avoid contact with poultry, birds and their droppings and should not visit live poultry markets and farms to prevent avian influenza, particularly during travel in the Christmas and New Year holidays," the spokesman said.

Mainland health authorities have reported 783 human cases of H7N9 since 2013

http://www.thestandard.com.hk/section-news.php?id=177527