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Since its publication in 1996, the Guide for the Care and Use of Laboratory Animals (National Research Council, Washington DC, National Academy Press) has become a primary source of information for institutional animal care and use committees (IACUCs) and research facility managers. In the ensuing years, recommendations relating to laboratory animal care have evolved in response to new scientific information and use of new technology such as ventilated caging. In this article, recent publications are examined to determine the potential impact of new scientific evidence on current practices for the housing and care of laboratory rodents. The discussion points out recent advances in technology and new knowledge of the conditions for the housing of various laboratory rodents, including cage space, single versus group housing, ventilated caging systems, thermoregulation, bedding materials, and enrichment. This new information is provided to aid IACUCs and facility managers in making decisions regarding the housing and care of laboratory rodents.

Susceptibility to oxygen toxicity was studied in three inbred and two hybrid strains of mice. Because in vitro studies have shown that the cytochrome P-450 enzymes can produce oxygen radicals and H202, we tested the hypothesis that inducibility of these enzymes might play a role in oxygen toxicity. Mice responsive to hepatic microsomal enzyme induction by aromatic hydrocarbons [C3H/HeJ, C3H/HeN, C3H/HeJ x DBA/2J (designated C3D2F1/J), C3H/HeN x DBA/2J (designated C3D2F1/N)] were more sensitive to the toxic effects of 100% oxygen exposure than were genetically unresponsive mice (DBA/2J). DBA/2J mice survived significantly longer exposure periods with less lung damage. Lung and liver cytochrome P-450 levels increased 2-to 3-fold in C3H and F1 mice during 100% oxygen exposure (maximum levels at 72-96 hr) and subsequently fell prior to death. No increases were seen in cytochrome P-450 levels in DBA/2J mice. Meta-

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A subhuman primate model was developed for study of the pathogenesis of infection with Coxiella burnetii. Cynomolgus monkeys (Macaca fascicularis) that were exposed to 10(5) mouse median infectious intraperitoneal doses of C. burnetii in a small-particle aerosol developed clinical signs of illness and pathologic changes characteristic of Q fever infection in humans. All monkeys had radiologic evidence of pneumonia by day 9. Antibodies to C. burnetii were detectable by the indirect fluorescent antibody test by day 7. These data indicate that the cynomolgus monkey is a suitable model for study of the pathogenesis of Q fever infection and may prove valuable in the evaluation of C. burnetii vaccines.