Summary
Contamination of tumor cell lines of hamster origin with lymphocytic choriomeningitis virus may be assumed to be widespread. These contaminated lines can cause the infection of hamster and other rodent populations used for tumor research. Such infections may spread the virus to humans in contact with the animals and may invalidate the experimental results. Human infections range from a subclinical course to one with signs of severe encephalomeningitis; the etiology may be missed if the physician is not aware of the patient's contact with possibly infected animals. Serological assay of adequate numbers of the laboratory rodent population for lymphocytic choriomeningitis virus is essential to proper surveillance. Elimination of the rodent infection requires primarily the destruction of contaminated and exposed animals, fumigation of the work area, and monitoring of new cell lines to prevent reinfection.