Risk factors for the persistence of bovine brucellosis in Sicily from 2008 to 2010.

Bovine brucellosis is a worldwide zoonotic disease, responsible for economic and reproductive losses in farmed animals. Despite the application of control and eradication measures, after several years the brucellosis situation still remains problematic in Sicily, one of the regions with the highest prevalence of infection in Italy. The objective of this paper is to evaluate the possible risk factors influencing the presence of bovine brucellosis in Sicily. Data on existing cattle herds in Sicily and on their structure in 2008, 2009 and 2010 were extracted from the national database (NDb) of holdings and animals. Several possible brucellosis risk factors were considered, in particular herd-related factors and the performances of the control activities carried out by the veterinary services and recorded into national animal health information system (SANAN). Statistical analysis (χ(2) and Mann-Whitney tests) and spatial cluster analysis using a simple spatial Bernoulli model were performed. The multivariable logistic regression was also performed using SPSS for Windows. The spatial distribution of infected herds shows two main clusters of infection, in Messina and in Siracusa provinces. The results of the statistical analysis performed show that the infection is associated to the largest herds (P<0.0001) and to beef and mixed herds (P<0.0001). A significant association can be observed between the infected status in 2010 and presence of positive animals in 2008 or in 2009 (P<0.0001). This article shows the importance of detailed and reliable epidemiological data through information systems, allowing a continuous monitoring of the health status of animal populations and also the evaluation and re-planning of veterinary activities.