First evidence of Brucella ovis infection in Republic of Croatia.

We researched the spread of Brucella ovis (B. ovis) infection in sheep during 2002 and 2003 in Croatia. A total of 30,635 sheep blood samples were examined using the enzyme-linked immunosorbent assay (ELISA). In 2002, 1014 out of 14,404 examined sheep blood samples (7%) from six counties gave positive reactions while 2060 (14.3%) were found suspicious. In 2003, 638 out of 16,221 examined sheep blood samples in nine counties (3.9%) tested positive while 1083 (6.7%) were suspicious. In rams and sheep that were serologically positive specific pathological changes were found in 68 (43.6%) out of 156 examined rams and in 5 (3.8%) out of 133 examined sheep. B. ovis was isolated from ram tissues from three counties and identified with classical microbiological procedures and the polymerase chain reaction (PCR). This research proves that Brucella ovis is present in sheep flocks in Croatia which is also the first proof of its existence in the country.