An environment sample taken from southeast China has tested positive for the H7N9 avian flu virus, the Ministry of Agriculture said on Thursday.

The sample was taken from a local poultry market in Fujian Province, bringing the total number of samples tested H7N9-positive to 52 in the country, the ministry said.

According to gene sequence analysis by the national bird flu reference lab, the virus strain detected in the sample is similar to that found in a sample of pigeon collected from a Shanghai marketplace that tested positive for the virus on April 4, the ministry said.

It has ordered the local government to properly dispose of the sample and increase monitoring and prevention work.

The virus has killed 33 people thus far since it was first detected in Shanghai in March.