A survey for Pneumocystis carinii in laboratory animal facilities

卡氏肺囊虫是一种重要的机会性肺病原体，可引起免疫功能低下的宿主，如可的松治疗的大鼠、小鼠或裸鼠的致命肺炎。虽然在日本和美国也出现了在裸鼠群中出现的病例，但在动物实验设施中是否出现了扩散还没有得到明确的结果。为了监测医学院校小鼠室的发病率，我们将462只裸鼠送到45个动物设施，每个房间3-10只。然后饲养6个月，进行寄生虫学和组织学检查。在43个设施的435只动物中，在12个设施（27.8%）的89只动物（20.5%）中检出了微生物。将调查房间分为3组，每组感染率计算如下：饲养从商业育种商购买的SPF小鼠的SPF房间（35个房间中有3个，8.6%），饲养常规动物的CV房间（12个房间中有7个，58.3%），饲养用户饲养动物的SPF房间（22个房间中有7个，31.8%）。CV房间的高感染率与可的松诱导实验的结果相吻合，该实验显示该疾病在常规大鼠和小鼠中普遍存在。有繁殖的SPF房间比没有繁殖的SPF房间感染率高。这意味着与短期动物实验的房间相比，可能需要更严格的饲养系统或手册来保护繁殖群体免受入侵。虽然在本研究中没有明确确定感染的因果关系，但严格的屏障系统似乎是有效的保护。

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.