HONG KONG • The Hong Kong authorities culled 4,500 birds at a wholesale market yesterday, two days after a suspension in trade of live poultry following a positive test for the H7N9 virus.

Staff in full-body protective gear killed chickens, pigeons and other birds at a temporary wholesale poultry market by stuffing them into a bin filled with carbon dioxide.

Trade in live poultry was suspended after the authorities said last Saturday that the avian flu virus was found in a faecal sample collected from a chicken at a market in Tuen Mun, a neighbourhood in the west of Hong Kong.

Hong Kong is particularly alert to the spread of viruses after an outbreak of severe acute respiratory syndrome swept through the city in 2003, killing 299 people and infecting around 1,800. Bird flu scares in the past two years have seen mass culls of up to 20,000 birds in Hong Kong. A spokesman for the Agriculture, Fisheries and Conservation Department said the latest cull included chickens and pigeons.

Chicken vendor Chan Shun Kuen said it was too early to estimate losses as the government had yet to announce when trade will resume, but she supported the move.

"Safety comes first," Ms Chan said. "Now we are starting from scratch and making sure everything is clean and hygienic. I support the government's decision."

H7N9 is a particular worry for the authorities as it does not kill infected chickens or cause them to develop symptoms, which allows it to spread undetected until contact is made with humans. The majority of human cases of H7N9 infection have been associated with direct or indirect contact with infected live or dead poultry, according to the World Health Organisation.

The first known human case of the H7N9 strain was reported in mainland China in March 2013, the World Health Organisation says. The virus spread to Hong Kong nine months later and killed three people.

REUTERS, AGENCE FRANCE-PRESSE