An unknown disease has stricken 20 villagers and killed nine of them in southwest China's Sichuan Province over the past four weeks, the provincial health department confirmed Saturday.

A team of experts from the Ministry of Health and Ministry of Agriculture are in Sichuan to provide medical aid and conduct epidemiological investigation.

Between June 24 and July 21, three hospitals in the city of Ziyang received 20 patients with similar symptoms. They all started with a high fever, fatigue, nausea and vomiting and became comatose later with bruises under the skin.

By July 21, nine patients had died and one had recovered and been discharged from hospital. Ten more were still being treated, six of whom in critical condition, the provincial health department said.

The patients, 19 men and a woman, are all farmers aged between 30 and 70. They are from 15 villages in Yanjiang and Jianyang and they all butchered sick pigs or sheep before coming down with the strange disease, a preliminary investigation has found.

But the detected cases are not interrelated and no infection has been found in any close contact of the patients, the investigators said.

Medical workers are carrying out laboratory work hoping to determine the exact cause of the disease, though experts suspect exposure to the sick, as well as the dead, animals is mainly to blame.

The local government has ordered all-out efforts to treat the patients and banned killing of sick pigs and sheep. It also instructed that animals killed by diseases are disinfected carefully and buried deep, and that farmers should avoid direct contact with sick or dead animals.

(Xinhua News Agency July 24, 2005)