Shanghai: The number of floating dead pigs found in a river in the Chinese metropolis has increased to 5,916, officials said Tuesday.
Workers have been busy collecting the pigs' corpses since Friday from the Huangpu river, Xinhua reported.
Municipal officials said the corpses will be disposed of safely.
On Tuesday, at least 20 dead pigs were collected, most of which had already started to decompose.
"It's common to find one or two dead pigs in the water, but too many corpses have been found this time," said a worker who has been collecting the dead pigs since Friday.
Tags pinned to the pigs' ears for tracing purposes indicate that they may have come from the upper reaches of the Huangpu in Jiaxing city in east Zhejiang province.
The tags, however, indicate only the animals' birthplace.
Laboratory tests found porcine circovirus, a virus that can spread among pigs but not among humans, in one water sample taken from the Huangpu.
All other tests showed no signs of irregular contaminants or disease, officials said.
The river is a major source of drinking water for Shanghai, a metropolis with 23 million people.
A local water supply company said the city's water quality has not been affected and is safe for human consumption.