Lewerin et al. Acta Veterinaria Scandinavica 2010, 52:7 http://www.actavetscand.com/content/52/1/7 Case Presentation The herd The affected herd consisted of 45 beef cows of mixed breed and their offspring, including calves and young stock. In total there were about 90 animals on the hold- ing. The calving period was mainly in autumn. The ani- mals were kept on pasture during the warmer part of the year and in a barn on deep straw bedding during winter. No supplementary feeding was given on pasture and during winter the animals were fed only roughage in the form of poor quality silage. No minerals were fed. During winter, the animals had access to a small pad- dock just outside the barn during daytime. Clinical history The animals were brought indoors in mid-October in 2008. They were vaccinated against bluetongue sero- type 8 with an inactivated vaccine within the official Swedish vaccination campaign [14] on the 25th of November. On the 29th of November one animal (ani- mal 1) died without any observed previous symptoms. The owner of the herd called his veterinarian to ask whether it could be a side effect of the vaccination but as this was rejected, he sent the carcass for routine destruction. The carcass was reported by the owner to be normal in appearance, with ordinary rigor mortis, no abnormal bleeding or abnormal appearance of any blood that was observed, and the carcass collector had the same recollection. On the 4th of December another animal (animal 2) died and two more (animals 3 and 4) were listless and feverish and the owner called his veterinarian. The ani- mals were found to have fever, a high pulse and increased, rattling, breathing sounds and were treated with danofloxacin and meloxicam. The carcass was sent for necropsy. It was a Thursday, and the veterinarian made sure that the transport would deliver the carcass to the regional laboratory the next day and that it would be necropsied immediately so as to ensure a good qual- ity of the investigation. However, the carcass did not arrive to the regional laboratory until the following Monday (8th of December). On Thursday evening (the 4th of December) another animal (animal 5) died and the owner cut it open and brought the liver, spleen, lungs and heart into the local veterinary clinic for exam- ination. During the night, the two animals that had been treated the previous day (animals 3 and 4) also died. On the 5th of December, the owner contacted his veterinar- ian who at this time also learned that the carcass sent for necropsy (animal 2) had not arrived in the labora- tory. She then contacted the National Veterinary Insti- tute (SVA) for advice. During this consultation, anthrax was discussed as a possible diagnosis but was regarded as less likely due to the feeding history and the lack of Page 3 of 8 typical signs (as reported by the owner, the carcass col- lectors and observed by the veterinarian herself) in the carcasses. Other possible causes that were discussed were pasteurellosis, clostridiosis, poisoning and mineral depletion. It was decided to take samples for histology and microbiology from the next animal that died if it could not be sent directly for necropsy. In the evening a calf died (animal 6), but the owner did not report it at the time and only sent it for destruction. On the 7th of December the owner culled one animal (animal 7) that was, he thought, on the verge of dying, and took out samples of spleen, lung and liver and sent them to SVA for culture and histology. However, the receiving laboratory did not realise that the animal had been culled and not died by itself and thus assumed that a diagnosis of septicaemia would have been readily made by bacterial culture. On the 8th of December the missing carcass (animal 2) arrived in the regional laboratory. Due to decomposition of the carcass a full necropsy could not be performed but a swab sample was taken from the spleen and sent to SVA for culture. On the night between the 9th and the 10th of Decem- ber another animal died (animal 8) and a separate trans- port was arranged to take the carcass directly to the regional laboratory for necropsy. When the vehicle arrived to the farm two more animals (animals 9 and 10) had died and were also taken to the laboratory. When the carcasses arrived in the laboratory and the first one was opened, the appearance (massive internal bleeding and non-coagulated blood) made the investi- gating veterinarians suspect anthrax and take actions accordingly. SVA was contacted and the other two car- casses were left unopened. It was decided to send blood samples from all three animals by courier to SVA and the samples arrived on the following morning (11th of December). After the diagnosis of anthrax was confirmed on the 12th of December, environmental samples were taken on the farm. These included various dust samples from stored roughage and straw for bedding and from feeding troughs as well as soil samples from areas just outside the barn where infected carcasses had been left on the ground until they were picked up for transport. The dust samples were collected both by hand (10-20 sam- ples from various storage areas) and with a small vacuum cleaner (some 20 samples from packed rough- age and feeding troughs). Soil samples were collected manually (5 samples from 2 spots). All people potentially exposed to bacteria and/or spores were given postprophylactic treatment with anti- biotics. The remaining animals were treated with long- acting antibiotics, to reduce the risk of further