Brucella suis biovar 2 isolations from cattle in Poland.

Bovine brucellosis is an infectious disease caused by bacteria of the Brucella genus, primarily by B. abortus, less frequently by B. melitensis, and occasionally by B. suis. In the European Union, brucellosis in cattle has been eradicated in most of the Member States, which are recognized as 'officially free from bovine brucellosis'. Nevertheless, cattle herds continue to be serologically monitored for the potential re-emergence of the disease. The aim of the presented study was to show the results of bacteriological investigations of cattle slaughtered in Poland in years 2002-2011 on account of positive serological reactions for brucellosis. Specimens (sera and tissues) from 176 cows were examined. Sera from the animals were tested using RBT(rose bengal test), SAT (serum agglutination test), CFT (complement fixation test), 2-ME (2-mercaptoethanol test), Coombs (Coombs antiglobulin test) and ELISA (enzyme linked immunosorbant assay). Tissue samples were cultured for Brucella, according to official protocols. All sera were RBT and SAT-positive, 170 of them were CFT- positive, whereas 6 other samples were CFT negative while positive in Coombs and ELISA. In bacteriological examination, B. abortus was not isolated. On the other hand, B. suis biovar 2 was isolated from 5 cows, which had never been reported previously in Poland. Three cows came from the same herd. Conventional, as well as, molecular investigations based on PCR methods, confirmed that the bacteria isolated bacteria belong to the B. suis biovar 2. In Poland, as in many other European countries, wildlife (wild boars and hares) constitutes a huge reservoir of the said biovar. The results of the presented research indicate that B. suis biovar 2 can easily infect cattle, and undoubtedly plays a role in the epidemiology and control of bovine brucellosis.