Anthrax outbreak in a Swedish beef cattle herd - 1st case in 27 years: Case report

Abstract

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.

Soil ingestion, nutrition and the seasonality of anthrax in herbivores of Etosha National Park

“…Anthrax outbreaks occur world-wide and are of concern for animal conservation (Leendertz et al 2004, Muoria et al 2007), wildlife management (Clegg et al 2007, Wafula et al 2008, agriculture (Mongoh et al 2008, Durrheim et al 2009, Lewerin et al 2010) and public health (Siamudaala et al 2006). Anthrax is caused by the bacterium Bacillus anthracis which can infect a wide range of animal species, but mortalities are most commonly observed in herbivorous mammals.…”

In silico and in vitro evaluation of PCR-based assays for the detection ofBacillus anthracischromosomal signature sequences

“…These assays target the markers BA5345, 21,65 PL3, 47 and BA5357, 46 respectively. Three of these assays are based on hydrolysis probe ("TaqMan assay"); the fourth uses SYBR Green chemistry.…”

Bayesian Networks for Evaluation of Evidence from Forensic Entomology

“…However, the outbreaks in Sweden in the early 21st century were associated with imported bone meal, which has been associated with the A lineage of Bacillus anthracis. 12 Thus, the probability of observing a particular anthrax strain would be different under the prosecutors' and defendants' hypotheses, and knowing the genotype (eg, lineage) of the anthrax in the dead cows would modify the likelihood ratio of the 2 hypotheses. The ability to combine circumstantial evidence from very different types of investigations, such as forensic entomology, witness statements, and type matching, makes the Bayesian networks a promising tool for investigating CBRN incidents.…”