KAMLOOPS, B.C.—Staff at an elementary school in Kamloops, B.C., were faced with a gym full of crying children after about 135 were stung by a swarm of wasps during their Terry Fox run today.

Diana Skoglund, communications manager for School District 73, says the Dufferin Elementary students were stung after running over a ground wasp nest.

The cross-country running team uses the trail every day but staff believe the high volume of kids today disturbed the nest.

Skoglund says parents and emergency responders were called immediately and all of the children were gathered in the gym to be treated with ice packs and sting remedy.

None of the kids with known anaphylaxis had extreme reactions, but two who had not been identified with anaphylaxis had strong reactions and were taken to hospital for observation.

Skoglund says many of the children went home with their parents, but many others returned to class after lunch.