MUTUAL VIRAL AND BACTERIAL-INFECTIONS AFTER HOUSING RATS OF VARIOUS BREEDERS WITHIN AN EXPERIMENTAL UNIT

Fifteen athymic rat strains from 11 breeding colonies were housed with in an experimental facility for an immunological study. Health status records supplied with 14 of the strains listed infections by Kilham's rat virus (KRV), Clostridium piliforme (Bacillus piliformis) and Paste urella pneumotropica for 2, 2 and 1 colonies respectively. In sera tak en previous to the study from euthymic rats of 10 strains, antibodies to KRV were detected in 3 strains, to Pneumonia virus of mice (PVM), R at corona virus (RCV) and Sendai virus in one strain each and to P. pn eumotropica in 2 strains. Only 2 of the KRV infections had been report ed by the supplier. During the study rats of all 10 strains developed antibodies to 2-4 of viral antigens. Eight out of 10 rat strains seroc onverted to 1-5 of the antigens C. piliforme (B. piliformis), Bordetel la bronchiseptica, Haemophilus spp., P. pneumotropica and Streptobacil lus moniliformis. Two rat strains housed in filtertop cages did not de velop antibodies to bacterial antigens. The potential detrimental effe cts of intercurrent infections on the outcome of the comparative immun ological study are discussed.