A soiled bedding sentinel system with rack sentinels and mom sentinels is described. Rack sentinels get soiled bedding from the other cages in the rack. the room sentinels get soiled bedding from the rack sentinels Only room sentinels are regularlytested. The method is economically effective and labor saving and has on two occasions proved efficient when mouse corona virus has appeared in an animal depanment at the Karolinska Institute

Hedenqvist, Patricia