“…In order to obtain this type of sanitary status, it is essential that animals be husbanded and kept in settings that are protected by strict sanitary barriers and frequently monitored, since many rodent infections are subclinical. 10 housing and environMental enrichMent Several aspects relative to the husbandry and housing of species are neglected. Group housing is important, but can give rise to aggression, hence causing pain, injury or death.…”