Epidemiological analysis of the 2015–2017 African swine fever outbreaks in Estonia

Publication date: Available online 9 October 2018Source: Preventive Veterinary MedicineAuthor(s): Imbi Nurmoja, Kerli Mõtus, Maarja Kristian, Tarmo Niine, Katja Schulz, Klaus Depner, Arvo ViltropAbstractAfrican swine fever (ASF) was first detected in the Estonian wild boar population in September 2014, while the first domestic pig farm was affected in July 2015. In the present study, we aimed to analyse, retrospectively, the epidemiology of the disease in all 26 outbreaks in domestic pig herds that occurred in Estonia during the period 2015–2017. Formal interviews were conducted to estimate the high-risk period for every farm, and to identify the possible origin of the ASF virus and the mode of virus introduction. Furthermore, the clinical manifestation of the disease as well as the course of the disease within the farm were investigated. Survival analysis was used to calculate herd incidence and to estimate outbreak risk. A hierarchical Bayesian space–time model was used to analyse the associations between outbreaks and ASF occurrence in wild boar. The spatial and temporal distribution of outbreaks was analysed to characterise the ASF epidemic in the Estonian domestic pig population from 2015 to 2017.The estimated high-risk period varied from seven to 20 days with a median of 11 days. On most of the affected farms, the first clinical signs were mild and not specific to ASF despite the high virulence of the circulating virus. Morbidity and mortality were often limited to...
Source: Preventive Veterinary Medicine - Category: Veterinary Research Source Type: research