Rabbit serum samples from eleven different research facilities were evaluated for the presence of immunoglobulin G against Pasteurella multocida by using an enzyme-linked immunosorbent assay (ELISA). Each facility which submitted serum samples also provided a brief history of each rabbit colony tested. Rabbits from colonies reported to have endemic P. multocida or of undetermined status had 83 (58.9%) of 141 rabbits that were positive. Colonies reported to be free from P. multocida had 110 (92.4%) of 119 rabbits that were negative by ELISA. The ELISA test described here showed a high degree of agreement (92-94%) with two other P. multocida ELISAs at different diagnostic facilities. This study confirms that an ELISA testing for serum antibodies against the P. multocida is a reliable diagnostic tool to screen colonies for P. multocida.

Fecal specimens from several laboratory animal species were tested for rotavirus antigen by Rotazyme II, a commercially available enzyme-linked immunosorbent assay (ELISA) that is widely used in human diagnostic studies. Fecal samples from rabbits, hamsters, guinea pigs, dogs, and cats tested negative; whereas those from rats and mice yielded a high proportion of positive results. Rats had the highest rate with 82% of the samples being positive. However, the presence of rotavirus in positive rodent samples could not be confirmed by virus isolation, electron microscopy or blocking ELISA using anti-EDIM mouse rotavirus serum. Several lines of evidence indicated that these positive reactions were false positives, apparently due to a non-specifically reacting substance in the diet of rats and mice. All the positive fecal samples were from rats and mice that had been fed nonautoclaved diet. Samples from rodents fed autoclaved diet were consistently negative in the Rotazyme test. When rats fed autoclaved diet were subsequently fed nonautoclaved diet, their stool converted from negative to positive within 6 hours. Conversely, rats with positive stool samples converted to negative within 15 hours when fed autoclaved diet. Similar results were found with mice. Positive fecal specimens and nonautoclaved rodent diet both contained a substance that apparently attached nonspecifically to the antibody coated beads used in the ELISA and reacted directly with the substrate in the absence of the conjugate. This substance was heat labile and trypsin sensitive, suggesting that it was a protein.

A high proportion of positive results was found in fecal specimens from mice and rats tested by Rotazyme II enzyme-linked immunosorbent assay, but the presence of virus could not be confirmed. Positive specimens and nonautoclaved rodent diet contained a substance that apparently attached nonspecifically to the antibody-coated beads used in the test and reacted directly with the substrate. Pretreatment of the beads with 0.1% bovine serum albumin eliminated this nonspecific activity.

Three years of quarantine data involving the prevalence of Feline Leukemia Virus (FeLV) in laboratory cats (Felis catus) was evaluated. Testing was performed using a commercially available ELISA system. Annual prevalence of infection ranged from 5.4 to 10.7% of the 937 cats tested. Results obtained with the enzyme linked immunosorbent assay (ELISA) system compared well with tests performed using an immunofluorescent antibody assay system (IFA). Seasonal periodicity was noted with higher infection rates among animals received in April. Holding period at the supplier and gender did not influence disease prevalence. The availability of a simple test system, the unacceptability of FeLV infected cats for research, the danger of transmission and a higher prevalence of infection than earlier reports indicated that supplier and user evaluation of research cats for FeLV would be prudent.

Response of rodents to experimentally induced subcutaneous infection was examined to determine whether laboratory rats used in invasive procedures have a superior ability to withstand wound infection than do hamsters and mice. Rats, hamsters, and mice were injected subcutaneously with 10(9), 10(7), and 10(5) colony-forming units of Staphylococcus aureus. Quantitative counts of viable S aureus from the injection site, bacteriologic cultures of heart blood, and histologic examinations of the subcutaneous tissues were performed. Multiple linear regression of the quantitative data and equality of regression lines among groups were determined. Results indicated that the ability to eliminate bacteria varied between species and depended on the dose injected within each species. Compared with hamsters and mice at all doses, rats eliminated bacteria faster and had the mildest and most rapidly organized inflammatory response after inoculation. Experimental bacteremia developed in 3.7% of all animals evaluated, with no species-specific pattern. The rat was more resistant to localized wound infection with S aureus than were hamsters and mice.