Department of Disease control & Epidemiology, National Veterinary Institute, SE-751 89 Uppsala, Sweden.
Acta Vet Scand. 2010 Feb 1;52(1):7. doi: 10.1186/1751-0147-52-7.
After 27 years with no detected cases, an outbreak of anthrax occurred in a beef cattle herd in the south of Sweden. The outbreak was unusual as it occurred in winter, in animals not exposed to meat-and-bone meal, in a non-endemic country. The affected herd consisted of 90 animals, including calves and young stock. The animals were kept in a barn on deep straw bedding and fed only roughage. Seven animals died during 10 days, with no typical previous clinical signs except fever. The carcasses were reportedly normal in appearance, particularly as regards rigor mortis, bleeding and coagulation of the blood. Subsequently, three more animals died and anthrax was suspected at necropsy and confirmed by culture and PCR on blood samples. The isolated strain was susceptible to tetracycline, ciprofloxacin and ampicillin. Subtyping by MLVA showed the strain to cluster with isolates in the A lineage of Bacillus anthracis. Environmental samples from the holding were all negative except for two soil samples taken from a spot where infected carcasses had been kept until they were picked up for transport. The most likely source of the infection was concluded to be contaminated roughage, although this could not be substantiated by laboratory analysis. The suspected feed was mixed with soil and dust and originated from fields where flooding occurred the previous year, followed by a dry summer with a very low water level in the river allowing for the harvesting on soil usually not exposed. In the early 1900s, animal carcasses are said to have been dumped in this river during anthrax outbreaks and it is most likely that some anthrax spores could remain in the area. The case indicates that untypical cases in non-endemic areas may be missed to a larger extent than previously thought. Field tests allowing a preliminary risk assessment of animal carcasses would be helpful for increased sensitivity of detection and prevention of further exposure to the causative agent.
27 年来瑞典南部一直没有发现炭疽病例，但后来在该国爆发了一起炭疽疫情。这次疫情较为罕见，因为它发生在冬季，感染的动物没有接触骨粉和肉骨粉，而且该国并非炭疽疫区。受感染的牛群包括 90 头牲畜，其中有小牛和幼畜。这些动物被养在有深稻草垫料的畜棚里，只喂粗饲料。在 10 天内，有 7 头动物死亡，除了发热外，没有出现典型的先前临床症状。据报道，这些尸体的外观正常，尤其是在尸僵、出血和血液凝固方面。随后，又有 3 头动物死亡，剖检时怀疑为炭疽病，并通过血液样本培养和 PCR 确认。分离株对四环素、环丙沙星和氨苄西林敏感。通过 MLVA 进行的亚型分析显示，该菌株与炭疽杆菌 A 谱系的分离株聚类。除了从感染的尸体被运走之前存放的地点采集的两个土壤样本外，畜舍的所有环境样本均为阴性。感染的最可能来源被认为是受污染的粗饲料，尽管实验室分析无法证实这一点。受污染的粗饲料与土壤和灰尘混合在一起，来自于前一年发生洪水的田地，随后是一个干旱的夏季，河水水位非常低，以至于可以在通常不会暴露的土壤上进行收割。据说，在 20 世纪初，动物尸体在炭疽爆发期间被倾倒在这条河中，因此该地区很可能仍有一些炭疽孢子存在。该病例表明，在非疫区，非典型病例可能比以前认为的更容易被忽视。现场检测可以对动物尸体进行初步风险评估，有助于提高检测的敏感性，并防止进一步接触病原体。
