Holt P S, Mitchell B W, Gast R K
U.S. Department of Agriculture, Agricultural Research Service, Southeast Poultry Research Laboratory, Athens, GA 30605, USA.
Avian Dis. 1998 Jan-Mar;42(1):45-52.
Salmonella enteritidis is currently thought to be transmitted principally through contact with infected individuals and ingestion of fecally contaminated materials. The present study was undertaken to determine if S. enteritidis could be spread in chickens by the airborne route and if induced molting could affect this mode of transmission. To test for airborne transmission, hens were placed in two rows of cages, the rows separated from each other by 1 m. One row of hens was challenged with S. enteritidis, whereas the other row remained unchallenged but exposed to the room air. Ventilation delivered within the room provided an even air distribution within the area and minimized directional air flow toward any set of cages. In Expt. 1, 4 of 12 and 9 to 12 exposed molted hens became infected with S. enteritidis after 3 and 8 days of exposure, respectively, compared with 1 of 12 and 0 of 12 unmolted hens sampled on the same days. Similar S. enteritidis levels were detected circulating in the air in the two rooms housing the hens. Expts. 2 and 3 examined airborne transmission in molted hens only. In Expt. 2, 2 of 12 exposed hens became infected with S. enteritidis at 3 days postchallenge, and this increased to 12 of 12.1 wk later. In Expt. 3, exposed hens were again housed in cages 1 m from challenged hens but were placed in every other cage to prevent transmission through contact with hens in adjacent cages. At day 3 post challenge, 0 of 12 exposed hens were culture positive for S. enteritidis, and this increased to only 3 of 10 positive hens at day 10. Large numbers of S. enteritidis shed by the molted challenged hens were recovered from the floors beneath the cages. These results indicated that, contrary to the generally held beliefs regarding organism spread, airborne transmission of S. enteritidis can occur and induced molting can provide the impetus for this event. As was observed previously, rapid dissemination of the organism to other members of the flock resulted through bird-to-bird contact.
目前认为肠炎沙门氏菌主要通过与受感染个体接触以及摄入受粪便污染的物质进行传播。本研究旨在确定肠炎沙门氏菌是否可通过空气传播途径在鸡群中传播，以及强制换羽是否会影响这种传播方式。为检测空气传播情况，母鸡被放置在两排笼子中，两排笼子之间相隔1米。一排母鸡用肠炎沙门氏菌进行攻毒，而另一排母鸡未受攻毒但暴露于室内空气中。室内提供的通风使该区域内空气分布均匀，并使朝向任何一组笼子的定向气流最小化。在实验1中，12只暴露的换羽母鸡中有4只在暴露3天后感染了肠炎沙门氏菌，9至12只在暴露8天后感染，而同一天采样的12只未换羽母鸡中分别有1只和0只感染。在饲养母鸡的两个房间的空气中检测到相似水平的肠炎沙门氏菌在循环。实验2和3仅研究了换羽母鸡的空气传播情况。在实验2中，12只暴露的母鸡中有2只在攻毒后3天感染了肠炎沙门氏菌，1周后这一数字增加到12只中的12只。在实验3中，暴露的母鸡再次被安置在距离攻毒母鸡1米的笼子中，但每隔一个笼子放置一只，以防止通过与相邻笼子中的母鸡接触而传播。在攻毒后第3天，12只暴露的母鸡中0只肠炎沙门氏菌培养呈阳性，到第10天这一数字仅增加到10只阳性母鸡中的3只。从换羽攻毒母鸡身上脱落的大量肠炎沙门氏菌在笼子下方的地面上被发现。这些结果表明，与关于病原体传播的普遍看法相反，肠炎沙门氏菌可通过空气传播，并且强制换羽可为这一传播过程提供动力。如先前观察到的，病原体通过鸡与鸡之间的接触迅速传播到鸡群中的其他个体。
