Natural infection of laboratory mice might therefore temporarily interfere with immune competence. Reovirus type 3. Reovirus type 3 is the most pathogenic reovirus of laboratory rodents. The primary importance of reovirus type 3 is as a contaminant of transplantable tumors and cell lines. Reovirus type 3 is a dsRNA virus in the family Reoviridae .
Transmission is thought to be primarily via direct contact.
However, Barthold et al. demonstrated that transmission of virus to cagemates or mothers of infected infants did not occur, indicating low contagiousness. The preponderance of the literature on the effects of reovirus type 3 reports on experimental infections. The effects of natural infections as well as relevant findings from experimental infections are reviewed here. Natural infection with reovirus-3 is nearly always asymptomatic. Experimentally inoculated mice have a wider scope of organ involvement.