The government of Changsha, Hunan Province, said Monday that no trace of infectious diseases had been discovered in the carcasses of pigs found in the Liuyang river that passes through the city, calling on residents to keep calm.

More than 70 dead pigs were found drifting in the water under the Liuyang river bridge in the city Saturday, followed by another 20 spotted on Monday morning, Liang Feicai, a press officer for the city government, confirmed to the Global Times Monday.

"Most were already decayed and the city authorities have removed, sterilized and buried all of them," said Liang. He added that the pigs' cause of death remains unknown as the local health department has examined samples but so far has not discovered traces of infectious diseases.

"Most had no ear tags so we cannot trace them, but it's highly probable that these pigs came from upstream areas. They were probably already dead before being thrown into the water," said Liang.

"Similar things have happened several times before, and our environmental department is monitoring the water quality so residents should stay calm," said Liang.

The city government has demanded farmers not throw carcasses into the river but bury them deeply.

The province has a major pig raising industry, with 79 million pigs raised in the province at any one time.

"The number of dead pigs found floating in Changsha is much smaller than the thousands from the Huangpu River in Shanghai," said Liang.

Dead pigs are not the only animal issue hitting headlines of late. The fatal strain of avian flu, H7N9, has been discovered in three provinces and a municipality with 24 people infected and seven killed as of late Monday.

Poultry businesses have been hence limited or suspended domestically as Xinhua News Agency reported Monday that officials in Jiangsu, Zhejiang and Shanghai had suspended businesses selling poultry and birds and ordered a general disinfection.