CORRELATION STUDY BETWEEN POSITIVE SEROLOGIC TESTS AND BACTERIOLOGICAL AND MORPHOPATHOLOGICAL EXAMINATION FOR BRUCELLA OVIS INFECTION IN THE AREA OF CLUJ COUNTY

Abstract

Research was conducted during 2000 - 2004 on a number of 60.986 blood samples from rammers, 530 pairs of testicles for bacteriological examination and 76 testicle samples processed for histopathology. Serologic and morphopathologic investigations were performed in the Veterinary State Laboratory Cluj (LSVS) and the bacteriology department in the Institute of Diagnosis and Animal Health (IDSA) Bucharest. Following the examination by serological RFC resulted a number of 4200 positive tests from 60.986 samples tested. Thus, the percentage of sickness caused by infectious epididimitis in rammers is 6.88%. Investigations by bacteriological examination, conducted at IDSA Bucharest on a number of 530 samples testicles (representing evidence and aries), revealed the presence of infectious epididimitis of rammers at 77.36%, 22.64% of the samples were negative. Having established a hierarchy of isolated germs involved in the aetiology of epididimitis we observed that 62.02% of cases are caused by Brucella ovis, 6.60% of cases by B. ovis in association with Arcanobacterium pyogenes and 7 ,74% by Arcanobacterium pyogenes only. Histological examination was conducted on a number of 76 testicles samples, of which 46 samples (60.52%) were with pathologic changes that can be attributed to infectious orchiepididimitis of rammers. Correlation is positive between histological examination and bacteriological examination, from a proportion of 100% testing positive for pathology, we managed to isolate Brucella ovis from 83.33%. Between necropsic exam results and serological examination by RFC, the correlation is negative, only 4.17% of the proportion of 100% diagnosed serological, presents pathological lesions of epididimitis. This type of relationship is valid also between serological examination by RFC and palpatory clinical examination. Considering RFC as a standard method to diagnose infectious epididimitis and comparing results with those of bacteriological examination carried out on the same samples that were diagnosed positive with RFC, we found that between these two methods there is a positive correlation. If RFC detected positive samples in the proportion of 100%, bacteriological examination detected the evidence of infected germs in a proportion of 77.36%, of which the Brucella ovis is 69.62%. Following bacteriological tests carried out on the same samples diagnosed as positive by serological examination (RFC), we find that the reaction of complement fixation although very sensitive, does not meet all the requirements, especially in regard of specificity, detecting also other bacterial antigens similar to B . ovis. For these reasons, in order to avoid false positive reactions from rammers with high economic and biologic value, testing is required to be made by at least two different methods (RFC and ELISA or RFC and bacteriological examination of semen).