Studies on the transmission of Pasteurellaceae in experimental rats
Effekt van hygienische maatregelen op de verspreiding van Pasteurellaceae infekties bij ratten in experimenten
Boot R, Elberts DJ, Jansen van 't Land C, Koedam MA, Steen BVL, Thuis HCW, Timmerman A, Veenema JL
RIVM Report 949102002
Studies using experimental animals are usually performed under hygienic regimens aimed to prevent infection by microorganisms that might influence the outcome of the studies. Insight into the factors contributing to the spread of various pathogenic microorganisms is however limited. The study on the effect of preventive measures on the spread of Pasteurellaceae infections in groups of rats was performed in 2 blocks of the new experimental animal facility. It was concluded that a rigorous regimen of changing clothes upon leaving and entering animal rooms clearly limits the transmission of infections between rats in different rooms. As a result within a block small microbiological units are created ('barriers within a barrier'). The study also revealed the existence of hitherto unknown sources of Pasteurellaceae contamination. In some of the Pasteurellaceae infected groups of rats it showed that the infection was limited to rats in some cages only. The reduction of the microbiological unit onto the level of the animal room and the uneven spread of infection within an animal room leads to a substantial increase in the number of sentinel animals that will be needed for proper monitoring of animal experiments.