The present study aimed to estimate the prevalence of antibodies against Brucella ovis-epididymitis, smooth-Brucella, leptospirosis, toxoplasmosis and Maedi-visna in sheep slaughtered in Minas Gerais, Brazil and to study their simultaneous occurrence, including caseous lymphadenitis, at sheep and flock levels. The study was conducted at a sheep slaughterhouse with Federal Inspection Service. Sera from 594 animals from 21 flocks were collected, in 2007. The agar gel immunodiffusion (AGID) was employed to detect anti-B. ovis and anti-Maedi Visna antibodies, whereas Rose Bengal (RB) and the 2-mercaptoethanol test (2ME) were used to test anti-smooth Brucella antibodies. For the detection of anti-Leptospira antibodies, sera were examined by microscopic agglutination test (MAT), while for the detection of IgG antibodies to Toxoplasma gondii ELISA was used. Prevalence of antibodies against smooth Brucella, B. ovis-epididimitis, Leptospira spp., toxoplasmosis and Maedi-Visna found in sheep from Minas Gerais was 0.00%, 24.04%, 25.96%, 10.46% and 3.08%, respectively; whereas the seroprevalence in flocks was 0.00%, 80.95%, 90.48%, 71.43% and 23.81%, respectively. Moreover, when data on antibodies anti-Corynebacterium pseudotuberculosis, previously obtained, were included, about 60% of the flocks showed animals that were exposed to four or more of the studied agents. However, only 25.47% of the sheep exhibited simultaneously antibodies against more than one pathogen. Thus, data from the present study on sheep slaughtered in Minas Gerais, Brazil, showed no antibodies to smooth-Brucella and a low frequency of antibodies anti-Maedi Visna lentivirus, and a high and widespread seroprevalence of B. ovis, Leptospira spp., and T. gondii among animals and flocks.

Out of 63 bacteriologically examined sanguineous fluids samples which were collected from Oedematous Skin Disease (O.S.D.) lesions, 37 isolates of C. pseudotuberculosis (C.p.) were recovered. The sensitivity tests revealed that isolates were highly sensitive to trimethoprim + sulphamethoxazole, amoxycillin, gentamicin and enrofloxacin. Diphtheria toxin (DT) produced by C. pseudotuberculosis of buffalo was determined by using the double immunodiffusion technique, it was applied on concentrated exotoxins which was prepared from C.p. isolates against Diphtheria toxin antiserum, its results were 15 (40.54%) positive and 22 (59.46) %) negative to presence of DT. Virulence of isolates having only phospholipase D ( PLD) or both PLD and DT was assayed by S/C inoculation of exotoxines prepared from isolates in guinea pigs, 15(40.54%) guinea pigs died within 18 hours while 22 (59.46%) guinea pigs died during 48 hours. An important point in this investigation that there have been very rare previous reports describing the production of DT by local isolates of C. pseudotuberculosis of buffalo.

Clinical examination of 380 rearing sheep revealed that 30 animal were suffering from skin abscesses with an incidence of (7.89%). Bacteriological examination of 30 swabs from affected sheep revealed isolation of 30 isolates of C. pseudotuberculosis (48.39%) , 18 isolates of S. aureus (29.03%) and 14 isolates of S. aureus subsp. anaerobius (22.58).The isolated bacteria were identified morphologically and biochemically.The results of animal pathogenicity test showed that C. pseudotuberculosis isolates were 100% pathogenic to guinea pigs and 80% of S.aureus isolates were pathogenic to mice, while all isolates of S. aureus subsp. anaerobius were pathogenic to mice. The dead animals showed haemorrhage and symptoms of septicaemia, C. pseudotuberculosis, S.aureus and S. aureus subsp. anaerobius were reisolated from the dead animals. Antimicrobial sensitivity of C. pseudotuberculosis , S. aureus and S. aureus subsp. anaerobius isolates to some antimicrobial agents which usually used in farms showed that from 90% to 100% of C. pseudotuberculosis isolates were sensitive to erythromycin, amoxicillin, tetracycline ,streptomycin, ampicillin and rifampicin while S. aureus isolates (from 55% to 66%) were sensitive to rifampicin,tetracycline ,erythromycin and streptomycin, while S. aureus subsp. anaerobius isolates were moderately resistant to all used antimicrobial agents.