Evaluation of the English bovine brucellosis surveillance system considering probability of disease introduction and non-random sampling

Publication date: Available online 12 February 2020Source: Preventive Veterinary MedicineAuthor(s): Alessandro Foddai, Tobias Floyd, John McGiven, Katherine Grace, Sarah EvansAbstractThe English surveillance system for bovine brucellosis was evaluated. The confidence in detecting at least one infected herd in the local population (surveillance system sensitivity or SSe), and the confidence in freedom from disease (PFree) adjusted (PFreeAdj) for the probability of disease introduction from abroad by imported animals (PIntro), were estimated for quarterly surveillance periods of 2016; because dairy herds were tested quarterly on bulk tank milk (BTM) with an antibody indirect ELISA. A stochastic model was developed and six surveillance components (representing also the local population strata), were evaluated. All English herds and their relative risk (RRs) of infection within each stratum were considered. The importance of each component was assessed using actual national data, which reflected non-random sampling. The contribution of the abortions testing was assessed with particular focus, because a decline in statutory submissions was observed in recent years. Beef herds without submissions (B-NoTest herds) at the laboratories were still considered as a population stratum, where infected cattle could be imported. Additionally, it was evaluated the importance of different hypothetical design between-herds prevalence (Ph) values, at which the country could be classified as “i...
Source: Preventive Veterinary Medicine - Category: Veterinary Research Source Type: research