A total of 115 children from the Guji Kindergarten, in Changsha township of Kaixian county, have been taken to three hospitals for treatment and observation, reported Xinhua citing sources with the county's public health emergency response centre.
Their blood and urine samples were sent to Chongqing city and Beijing for tests.
Health officials carried out a check of all the nearly 300 children in the privately-owned kindergarten after some of them showed the symptoms Wednesday.
Local health experts from as well as the National Health and Family Planning Commission have begun a coordinated investigation into the cause of the disease outbreak.
Meanwhile, hospitalised children were in stable condition, except the two of them who were in a relatively serious but not life-threatening condition, sources said.