An eighth person in China has died after being infected with the new H7N9 strain of bird flu, according to state media that also reported the number of people infected has remained at at least 24.

The latest death was reported Tuesday in Jiangsu province, north of Shanghai, authorities told Xinhua. Authorities confirmed a man had been infected with H7N9.

Jiangsu had the second-most reported cases in the country as of Monday, with eight people infected. In Shanghai, 11 people were exposed, and five of them died.

The source of infection and mode of transmission are currently unknown, according to the World Health Organization, which is investigating animal to human, and human to human transmission, but there is no evidence that the virus is spreading from person to person.

The WHO may send international experts to China to help investigate.

H7N9 is believed to circulate in poultry stocks without affecting birds, making it harder for experts to identify and eliminate outbreaks in birds.

Shanghai and the capital cities of neighbouring Zhejiang and Jiangsu, which have all reported H7N9 cases, have halted the sale of live poultry. Shanghai also slaughtered all fowl at a market where the virus was detected in pigeons being sold for meat.

90,000 pigeons will be vaccinated

Meanwhile, a pigeon association is halting its bird races and advising members to cage their pets for up to two months. The precautions are meant to help prevent infection with the bird flu virus.

The Hangzhou Carrier Pigeon Association will vaccinate up to 90,000 pigeons to protect against bird flu types. No vaccine exists for H7N9 yet.

Raising carrier pigeons is a popular hobby in China, but the birds have become a source of worry after live birds in Shanghai were found infected with H7N9.

With files from The Associated Press