File Photo: Xinhua

A total of 493 residents in Shouxian county, East China's Anhui Province suffered from fever, vomiting, abdominal pain and diarrhea with a preliminary investigation finding that it was caused by Shigella infection.

Since Thursday, hundreds of local residents have experienced the above-mentioned symptoms and local authorities have established a work group to carry out personnel treatment, the local government said on  its Weibo account on Sunday. 

Local hospitals took in 289 people and the patients' conditions have generally improved, with some patients being cured and discharged, said the post. 

A preliminary investigation showed the outbreak was caused by Shigella infection, the local authorities said. To prevent the waterborne infection, a water plant in the county was closed on Friday and the relevant disposal work is being  carried out.