Ninety-three teachers and students have been quarantined in a high school in south China's Guangxi Zhuang Autonomous Region, as 69 students of the school have contracted acute hepatitis A over the past 20 more days, local health official said on Sunday.

At press time, 56 of the 69 students are still hospitalized.

Yu Yang, deputy director of the Pingnan County Health Bureau, said Siwang Township reported 77 acute hepatitis A cases from July 21 to Aug. 9, 69 of whom are students of the Siwang Township No. 2 High School. As of Sunday, 13 of the 77 patients have recoverd and been discharged from hospital.

Yu did not disclose any other new cases of the disease.

Pingnan county health authorities conduct health check on all the teachers and students of school and their family members to block the spread of the disease.

The school has 1,800 teachers and students, 1,557 of whom have undergone tests, which proved 188 to be anti-HAV-IGM positive. Currently, 93 people were quarantined at school.

Medical practitioners of Pingnan county have injected human immune glob n to curb contract of the disease and lighten the symptoms of the patients.

Cause of the outbreak is unknown, said Zhang Jianquan, head of the Pingnan County Health Bureau.

Zhang said bad drinking water quality may be blamed for the outbreak.

Local epidemic prevention station's tests show that all the water quality in the five wells which provide drinking water for the school is far from meeting the standards for safe drinking water set by the government.

Currently, 380 students of the school, who are now spending the summer vacation with their parents in Guangdong and Fujian provinces, have not undergone health check, said Li Desheng, headmaster of the school.

Whether this group of students have contracted hepatitis A is unknown, Li said.

(Xinhua News Agency August 14, 2006)