Abstract
Wild house mice (Mus musculus) persistently infected with high titres of lymphocytic choriomeningitis virus (tolerant infection) are the source of human inapparent and overt infections, the latter sometimes being of a serious nature. Infections have also occurred in laboratory staff studying the virus and in others handling biological materials contaminated with it. The literature is reviewed.
Great Britain is one of the countries in which pockets of infected wild house mice exist, and these can be a source of infection for laboratory mouse colonies within which congenital transmission through tolerantly infected females would be the main method of spread. Overt signs of the infection may not be detected in mice, and absence of the infection would be certain only if 100% of the litters from which future breeding stock are to be selected were monitored for infectivity and maintained in isolation from unmonitored mice. A suitable monitoring technique is described.
It must be the aim of all breeders of mice to eliminate the possibility of their colonies being a potential hazard to human health. The life-long high infectivity of tolerantly infected mice provides a long-term source of infection for those who handle them and for other biological materials in which the virus can persist without recognition.