Dhillon A S, Roy Parimal, Lauerman Lloyd, Schaberg Dennis, Weber Sylvia, Bandli Daina, Wier Fonda
Department of Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Puyallup, WA 98371-4998, USA.
Avian Dis. 2004 Sep;48(3):675-80. doi: 10.1637/7113.
A new facility was designed to hold 1.8 million birds in 10 houses; chickens were placed in five of the houses, and the remaining five houses were under construction when this outbreak occurred. An increase in mortality was reported in five houses; however, mortality in house 7 was quite high. Well-fleshed birds were suddenly found dead without a significant drop in egg production. The middle and distal intestines were distended with gas, congested, thin walled, atonic, and bluish or pale in color with sloughed mucosa in some places. Necrotic enteritis was diagnosed as the cause of increased mortality. The ingesta in the crop occasionally contained flies. The 4-wk mortality in house 7 was 6.55% with a loss of 10,898 chickens. The 4-wk mortality rate in the other houses ranged from 0.54% to 1.98%. The houses affected with necrotic enteritis were treated for coccidiosis with amprolium because low numbers of the oocysts were present in the intestinal specimens of some of the chickens. Household bleach was added to the water at a dilution of one part bleach to 1040 parts water to control bacterial contamination. The fly (Musca domestica) population was out of control. Clostridium perfringens was isolated from the alcohol-washed macerated flies caught from houses 4 and 7. Dead flies were often seen in the feed troughs. The chickens may possibly have had C. perfringens infection as a result of consumption of dead flies or their secretions/excretions. The alcohol-washed, macerated, clarified fly extract from the affected houses caused death in 11 inoculated mice and paralysis in one mouse. Similarly, illness and mortality were present in four mice inoculated with clarified intestinal contents. The bacterium isolated on anaerobic culture was identified as C. perfringens by polymerase chain reaction. The disease was brought under control after straw was added and mixed in with the litter. As a result, the litter temperature increased, causing a decrease in the fly population. This study suggests that flies in the poultry houses acted as mechanical transmitters of C. perfringens and that the development of necrotic enteritis was by ingestion of bacteria present in the flies and their secretions/excretions.
新建了一个设施，设计容纳10栋鸡舍中的180万只鸡；疫情发生时，鸡被安置在其中5栋鸡舍，其余5栋正在建设中。据报告，5栋鸡舍的死亡率有所上升；然而，7号鸡舍的死亡率相当高。发现膘情良好的鸡突然死亡，产蛋量却没有明显下降。中肠和远端肠管胀气、充血、壁薄、无张力，颜色呈蓝色或苍白，有些地方黏膜脱落。坏死性肠炎被诊断为死亡率上升的原因。嗉囊内的食糜偶尔会有苍蝇。7号鸡舍4周龄时的死亡率为6.55%，损失了10898只鸡。其他鸡舍4周龄时的死亡率在0.54%至1.98%之间。对受坏死性肠炎影响的鸡舍用氨丙啉治疗球虫病，因为部分鸡的肠道标本中发现少量卵囊。家用漂白剂以1:1040的比例稀释后加入水中，以控制细菌污染。苍蝇（家蝇）数量失控。从4号和7号鸡舍捕获的经酒精冲洗、捣碎的苍蝇中分离出产气荚膜梭菌。饲料槽里经常能看到死苍蝇。鸡可能因食用死苍蝇或其分泌物/排泄物而感染产气荚膜梭菌。从受影响鸡舍提取的经酒精冲洗、捣碎、澄清的苍蝇提取物导致11只接种小鼠死亡，1只小鼠瘫痪。同样，接种澄清肠道内容物的4只小鼠出现疾病和死亡。通过聚合酶链反应将厌氧培养分离出的细菌鉴定为产气荚膜梭菌。添加稻草并与垫料混合后，疾病得到控制。结果，垫料温度升高，苍蝇数量减少。这项研究表明，鸡舍中的苍蝇是产气荚膜梭菌的机械传播者，坏死性肠炎的发生是由于摄入了苍蝇及其分泌物/排泄物中的细菌。
