| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1989: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1988: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
Pneumocystis carinii is an important opportunistic pulmonary pathogen which causes fatal pneumonia in immunocompromised hosts such as cortisone-treated rats and mice or nude mice. While a few outbreaks of the disease in nude mouse colonies have been reported in Japan and the U.S., the spread in facilities for animal experiments has not been clarified yet. To monitor the incidence in mouse rooms in medical colleges, we sent a total of 462 nude mice to 45 animal facilities as a unit of 3-10 animals per room. Then, the animals were kept for a period of 6 months, and examined parasitologically and histologically. Out of 435 animals in 43 facilities, the organisms were detected in 89 animals (20.5 %) in 12 facilities (27.8 %). The surveyed rooms were divided into 3 groups and each infection rate was calculated as follows; SPF rooms in which SPF mice purchased from commercial breeders were kept (3 out of 35 rooms, 8.6 %), CV rooms for conventional animals (7 out of 12 rooms, 58.3 %), and SPF rooms in which animals were bred by users (7 out of 22 rooms, 31.8 %). High infection rates in CV rooms coincided with the result of cortisone induced experiment, which revealed a prevalence of the disease in the conventional rats and mice. SPF rooms with breeding showed a rather high infection rate to SPF rooms without breeding. This means that a much stricter rearing system or manual is probably necessary to protect from invasion in the breeding colonies in comparison with the rooms for short term animal experiments. Although the causal effect of infection was not determined clearly in this study, a strict barrier system seems to be effective for protection.
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