Microbiological monitoring in individually ventilated cage systems.

Housing rodents in IVC racks has many advantages over conventional cages but also presents unique challenges related to health monitoring. The authors review the issues to consider in design of a sentinel program using IVC systems.

Efficacy of three microbiological monitoring methods in a ventilated cage rack.

The use of individually ventilated caging (IVC) to house mice presents new challenges for effective microbiological monitoring. Methods that exploit the characteristics of IVC have been developed, but to the authors' knowledge, their efficacy has not been systematically investigated. Air exhausted from the IVC rack can be monitored, using sentinels housed in cages that receive rack exhaust air as their supply air, or using filters placed on the exhaust air port.

Confirmed persistent mouse hepatitis virus infection and transmission by mice with a targeted null mutation of tumor necrosis factor to sentinel mice, using short-term exposure.

Mouse hepatitis virus (MHV) infection in immunocompetent mice is typically self limiting, and transmission is short lived. With the recent surge in the development of genetically engineered mutant mice with alterations in immune system components, however, MHV clearance may be disrupted. We report confirmed persistent transmission of MHV from tumor necrosis factor (TNF) knockout mice, B6.

Rodent quality assurance testing: use of sentinel animal systems.

The ability to produce unique strains of genetically engineered mice has revolutionized biomedical research, but has also complicated the maintenance of "clean" facilities through an increase in the movement of animals between facilities and the production of immunodeficient strains. The authors discuss the use of sentinel and quarantine programs to minimize disease transmission between laboratory mice.