Shigella sonnei bacteria were found in the feces of patients who are among hundreds treated for food poisoning in northern China, local health authorities said Wednesday.
According to the county government of Zhengding, Hebei Province, more than 300 school children have been hospitalized since Tuesday afternoon, but none face life-threatening disease.
According to doctors, patient blood test reports showed high white blood cell levels, indicating infection.
Experts said the discovery confirmed that the students were suffering from gastrointestinal diseases caused by Shigella sonnei bacteria.
"Shigella sonnei bacteria can breed in food and water at an optimum temperature, which can easily cause bacillary dysentery," said experts, adding that severe cases of shigellosis can be so serious that patients, particularly young children and the elderly, need to be hospitalized.
An investigation into the cause of the outbreak is under way.
A total of 121 people died of food poisoning in China in 2015, 10 percent more than the previous year, said the National Health and Family Planning Commission
The number of people who suffered from food poisoning last year was 5,926, up 4.7 percent, in a total of 169 cases.
Microbiological food poisoning was the cause of most illness, while poisonous material, including mushrooms, was the cause of most deaths.