A murine model of Streptococcus suis type 2 meningitis in the pig.

When young or adult mice were infected experimentally with isolates of Streptococcus suis type 2 of known pathogenicity for pigs, the organisms produced disease, young mice being more susceptible than adults. An isolate of S suis type 2 less pathogenic for pigs also appeared less pathogenic in mice. The organism could be reisolated from infected mice for up to 42 days. Inoculum size was one factor influencing the likelihood of an individual mouse developing meningitis following intravenous inoculation. Transmission of the organism from inoculated to in-contact mice occurred in young mice after intravenous or oral administration. These studies indicate that the behaviour of S suis type 2 in mice resembles its behaviour in pigs.