At least 905 children have called in sick to schools in a suspected case of mass food poisoning in Japan 's Shizuoka Prefecture , forcing the local government to cancel classes at 15 elementary schools to prevent the outbreak from spreading . The children from Hamamatsu , a coastal city about 125 miles southwest of Tokyo , suffered vomiting and diarrhea , officials said Thursday , while 41 teachers and staff showed the same symptoms . Authorities suspect the outbreak was caused by norovirus , a common source of foodborne illness . The highly contagious virus was `` detected in about half of the stool samples taken from sick pupils , '' said Horihiro Ishizaka , a Hamamatsu city public relations official . The city 's hygiene office is testing school lunches eaten by the students to confirm the cause of the outbreak , Ishizuka said . Local news reports said the schools used an ingredient from one shared supplier . The city has closed most of the affected schools and canceled classes at others through Friday in wake of the incident , which comes less than a month after 1,400 people across Japan fell ill after eating frozen foods that may have been tainted with pesticides .
1,400 of children fall ill with symptoms of food poisoning in Japan , Hamamatsu . Authorities suspect norovirus caused the outbreak . Health officials are testing school lunches to determine the origin of the illness . The case follows a food poisoning scare that left Hundreds people ill in less than a month .