State media and local authorities have confirmed that more than 150 Chinese villagers, many of them children, may have been infected with hepatitis C by a clinic that reused old needles.
Nineteen people who received treatment at the privately-run clinic in central China have tested positive for the disease, which the World Health Organisation says can lead to cirrhosis of the liver and liver cancer.
Another 98 are suspected to have been infected in Henan province, where the clinic is located, the state-run Beijing Times reported.
The paper quoted local officials as saying the clinic regularly reused needles, but that they were still trying to establish whether it was to blame for the outbreak.
A statement from health authorities in neighbouring Anhui province said 43 patients who attended the clinic had been screened for the disease, and that the outbreak was "probably due to unsafe injections".
Hepatitis C is transmitted through contact with the blood of an infected person.
The WHO says more than 350,000 people die from hepatitis C-related liver diseases globally each year.