Isolation of Brucella abortus and Brucella abortus, strain 19, from cattle.

Tissues from 104 cows in herd were examined for brucellae. Brucella abortus, strain 19, was isolated from 22 cows, a field strain of B abortus, biotype 1, was isolated from 9 cows, and both strains were isolated from 2 cows.     

Arthropathy associated with Brucella abortus strain 19 vaccination in cattle. II. Experimental studies

Attempts to reproduce in calves the arthropathy associated with Brucella abortus strain 19 (S19) vaccination by direct intra-articular injection of S19 or virulent Brucella cells were unsuccessful. Intra-articular injection of rabbits and a calf with immune complexes isolated from the synovial fluid of a field case produced clinical and histological signs of arthropathy accompanied by the development of rheumatoid factor.     

Arthropathy associated with Brucella abortus strain 19 vaccination in cattle. I. Examination of field cases

Thirty cows presenting with lameness and persistent serological reactions to Brucella abortus had chronic granulomatous arthropathy of the femorotibial and occasionally other joints. Attempts to culture Brucella or other pathogens gave negative results but organisms of Brucella morphology were seen in fluorescent antibody-stained cryostat sections of synovial tissue. The synovial fluids contained high titres of antibodies to B. abortus and Yersinia enterocolitica O:9 and had elevated total protein and immunoglobulin concentrations showing an oligoclonal electrophoretic profile. Immune complexes and rheumatoid factor were detected in some of the fluids.     

Control of small ruminant brucellosis by use of Brucella melitensis Rev.1 vaccine: laboratory aspects and field observations

Brucellosis vaccines are essential elements in control programs. Since first developed in the mid-1950s, the Brucella melitensis vaccine strain Rev.1 has been used worldwide and its significant value in protecting sheep and goats in endemic areas recognized. This review provides historical background on the development of the vaccine, its use and field complications arising in Israel following changes in the strain’s pathogenicity. The urgent need for resolving cases of vaccine strain excretion in the milk, horizontal transfer and a unique case of human infection has led to identification of an atypical B. melitensis biovar 1 strain that resembles strain Rev.1 in susceptibility to penicillin and dyes. An omp2 based PCR method has been developed that traced the lineage of Israeli B. melitensis biovar 1 strains. This locus serves as an epidemiological tag for the Rev.1 vaccine strain. Despite the rapid development of new approaches in the field of vaccination, it is anticipated that in the near future the Rev.1 vaccine would remain the only accepted vaccine in national control programs.     

Serological response of cattle, sheep and goats in Kenya vaccinated with killed Brucella melitensis strain H38 adjuvant vaccine

The antibody responses of cattle, sheep and goats to the Brucella melitensis H38 adjuvant vaccine were monitored by serum (tube) agglutination, complement fixation and Rose Bengal plate tests. High and persisting antibody titres were induced by a single dose of this vaccine in all three species. It would be difficult to classify reactors by commonly used diagnostic tests in a control or an eradication programme using the H38 adjuvant vaccine.     

Cell-mediated immune responses in cattle adult-vaccinated with Brucella abortus strain 19 and in cattle infected with Brucella abortus field strain.

Cell-mediated immune responses in cattle adult-vaccinated with Brucella abortus strain 19, cattle infected with B abortus field strain, and nonexposed cattle were studied by an in vitro lumphocyte-stimulation test (LST). Lymphocytes were prepared from peripheral bovine blood by the Ficoll-diatrizoate technique, and results were assayed for [3H]thymidine incorporation into DNA by liquid scintillation spectrometry. Serotests and bacteriologic isolation attempts were conducted simultaneously with LST. Lymphocytes from cattle infected with field strains had significantly (P = 0.01) higher specific lymphocyte-stimulation inexposed controls. The LST, the serum standard-tube agglutination test (STT), the Rivanol (RIV) test, and the complement-fixation (CF) test correctly classified cattle from which field strains and strain 19 of B abortus were isolated. The LST was negative in cattle vaccinated with B abortus strain 19 (nonshedding), but the three serotests had many false-positive reactions. The CF test had the least false-positive reaction, followed by the RIV test, and the STT was the least specific. Well before the three serotests became positive, the LST was positive in samples from some cattle during the incubation period of the infection. There was little or no correlation between cell-mediated immune responses (as measured by LST) and serum antibody responses (as measured by STT, RIV test, and CF test) in vaccinated but culture-negative cattle and in some nonvaccinated cattle during the incubation period.     

An ELISA with Brucella lipopolysaccharide antigen for the diagnosis of B. melitensis infection in sheep and for the evaluation of serological responses following subcutaneous or conjunctival B. melitensis strain Rev 1 vaccination.

An indirect enzyme-linked immunosorbent assay (ELISA) with unpurified Brucella melitensis smooth lipopolysaccharide (S-LPS) as antigen was evaluated for the serological diagnosis of B. melitensis infection in sheep in comparison with the Rose Bengal (RB), complement fixation (CF), radial immunodiffusion (RID), microplate agglutination (MA) and rivanol agglutination (RIV) tests. Tests RB and CF detected as positive each of the 77 sera from B. melitensis-infected animals tested, the RID (74), MA (76) and the RIV (72) were less sensitive. However, all tests compared were negative when 77 sera from Brucella-free rams were tested. While subcutaneous Rev 1 vaccination induced high response levels in any of the tests, low level responses were obtained upon conjunctival vaccination, particularly in ELISA and RID tests.     

The "effects" of Rev-1 vaccination of sheep and goats on human brucellosis in Greece

Vaccination of young animals (3-6-month-old sheep and goats) with Rev-1 vaccine for 15 years in Greece, importantly decreased the abortions in sheep and goats as well as the incidence of brucellosis in humans. After the stop of vaccination in 1994, all over Greece, the prevalence of brucellosis in animals and the incidence in humans quickly increased. It was a positive rank correlation (0.90) among these variables. Once an emergency mass-vaccination programme of young and adult animals with Rev-1 vaccine was started in 1998, the human incidence again decreased. The association of the vaccination coverage of animals and incidence of brucellosis in humans was not linear; the decrease in human brucellosis incidence was observed when the vaccination coverage of animals was >30%.     

Specific lymphocyte stimulation in cattle naturally infected with strains of Brucella abortus and cattle vaccinated with Brucella abortus strain 19.

Cell-mediated immune responses in cattle naturally infected with strains of Brucella abortus and in cattle vaccinated with B abortus strain 19 during calfhood were studied by an in vitro lymphocyte-stimulation procedure. Lymphocytes were prepared from peripheral bovine blood by the Ficoll-diatrizoate technique, suspended in RPMI-1640 medium (1.5 X 10(6) lymphocytes/ml), cultured with B abortus-soluble antigen or phytohemagglutinin, and incubated for 6 days. Sixteen hours prior to termination of incubation, cultures were labeled with 1 muCi of [3H]thymidine (3HdT) and, after harvesting, assayed for 3HdT incorporation into DNA by liquid scintillation spectrometry. Lymphocytes from cattle with bacteriologically confirmed isolation of B abortus underwent a significantly higher lymphocyte stimulation with B abortus-soluble antigen than did cattle vaccinated with B abortus strain 19 during calfhood (P less than 0.005). Standard seroagglutination tests were conducted simultaneously with lymphocyte-stimulation tests, but there was no apparent correlation between levels of humoral antibodies and the cell-mediated immune responses as measured by in vitro specific lymphocyte stimulation.     

Value of serologic reactions at 2 months following strain 19 vaccination of cattle herds with brucellosis

Non-reactor cows in a dairy herd and six beef herds quarantined because of brucellosis were vaccinated with Brucella abortus Strain 19 and tested by rivanol and complement-fixation (CF) tests. Cows with rivanol 100 and CF 80 test titers at 2 months post-vaccination (p.v.) were defined as test positives. In the dairy herd, 46 test positives were diagnosed as follows: 17 (37%) had field strain infection; 1 (2%) had a Strain 19 infection; an additional 18 (39%) were brucellosis reactors at 4 months p.v.; 10 (22%) had declining or negative serologic tests at 4 months p.v. In the beef herds, 58 test positives were diagnosed as follows: 19 (33%) had field strain infection; 5 (9%) had Strain 19 infection; an additional 21 (36%) were brucellosis reactors at 6 months p.v.; 13 (22%) had declining or negative serologic tests at 6 months p.v.

Since the majority of the test-positive cattle were diagnosed as either infected with B. abortus or brucellosis reactors, segregation of these cattle should reduce field strain exposure for the remaining cattle in the herd and therefore reduce the number of new cases of brucellosis.     

Survey of brucellosis in goats and sheep in the yemen arab republic: Comparison of tests forBrucella melitensis infection in sheep

Summary Sera from 538 Yemeni goats and 690 Yemeni sheep were screened for brucellosis by the Rose Bengal Plate Test (RBPT) and reactors confirmed by the complement fixation test (CFT) and the serum agglutination test (SAT). The prevalence among goats was 0·4% and among sheep 0·6%. The prevalence among 183 imported goats and sheep was 4·4%. The sensitivity and specificity of three seřological tests available for the diagnosis of brucellosis—CFT, RBPT and SAT—were compared using ovine sera obtained throughout an outbreak of abortion due toBrucella melitensis. The RBPT and the SAT were relatively insensitive compared with the CFT (71 and 44% respectively) and the RBPT was as specific as the SAT when suspicious sera were included. The results suggests that the SAT adds little information when used with other tests and the RBPT has limited applications as a screening test for ovine brucellosis.

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Resumen Se examinaron 538 sueros de cabras Yemeni y 690 de ovejas Yemeni, para detectar brucelosis, mediante la prueba Rose de Bengala (RB) confirmando los reactores con la prueba de fijación del complemento (FC) y de seroaglutinación (SA). La prevalencia en cabras fue de 0.4% y en ovejas de 0.6%. La prevalencia dentro de 183 cabras y ovejas importadas fue de 4.4%. La sensibilidad y especificidad de las tres pruebas serológicas utilizadas, se comparó usando suero ovino obtenido en un brote confirmado de brucelosis porBrucella melitensis. Las pruebas de (RB) y (SA) fueron relativamente insensibles comparadas con la de (FC) (71% y 44% respectivamente), y la de (RB) fue tan específica como la de (SA). Los resultados sugieren que, la prueba de (SA) a?ade poca información cuando se utiliza con otras pruebas, y que la de (RB) tiene aplicación limitada para un diagnóstico de población para brucelosis ovina.

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Résumé Des sérums provenant de 538 chèvres et 690 moutons du Yemen on été analysés pour le dépistage de la brucellose par le test des lames au Rose Bengale (TLRB) et les réactions positives ont été confirmées par le test de la fixation du complément (FC) et le test d'agglutination du sérum (TAS). Le taux de fréquence chez les chèvres était de 0,4 p. 100 et chez les moutons de 0,6 p. 100 Le taux de chez 183 ovins et caprins importés étai de 4,4 p. 100 La sensibilité et la spécificité des trois tests sérologiques utilisés dans le diagnostic de la brucellose—TLRB, FC et TAS—ont été comparés sur des sérums ovins obtenus tout au long d'une épidémie d'avortements dus àBrucella melitensis. Le test au Rose Bengale et le test d'agglutination du sérum se sont montrés relativement peu sensibles comparés à la fixation du complément (7 et 44 p. 100 respectivement) et la spécificité du test au Rose Bengale était égale à celle du test de l'agglutination du sérum lorsque des sérums douteux étaient inclus. D'après les résultats, le TAS, utilisé conjointement avec les autres tests apporte peu d'informations supplémentaires et le TLRB a des applications limitées en tant que test de dépistage de la brucellose ovine.

     

The characteristics of a variant strain of Brucella melitensis Rev 1

Circumstantial evidence is presented for the occurrence of a variant of a vaccine strain of B. melitensis Rev 1, designated "FSA" (foreign South African). FSA resembles Rev 1 in its reactions to penicillin and streptomycin but reacts closer to a field strain of B. melitensis as regards dye (thionine and basic fuchsin) sensitivity and colony size. Although colonies of Rev 1 were consistently smaller than other B. melitensis strains, their size was 0,75 mm as opposed to the 1-2 mm reported in the literature, while B. melitensis 16M colonies were 1,25-1,5 mm as opposed to the 3-4 mm previously reported. Rev 1 was found to be urease positive, unless a test of low sensitivity was applied.     

Response of Bali cattle (Bos javanicus) to vaccination with Brucella abortus strain 19 in West Timor

A trial was conducted in two villages (one containing cattle infected with brucellosis and one not containing infected cattle) in Timor, Indonesia to determine the serological response to vaccination with Brucella abortus strain 19 in Bali cattle (Bos javanicus) (n = 599). Mature female cattle were immunised with low-dose strain 19 (2x10(8)-6x10(8) colony forming units) and calves (6-12 months) with high-dose strain 19 (4x10(10)-12x10(10) colony forming units). Other mature females and calves were inoculated with sterile vaccine diluent and formed a non-vaccinated in-contact control group. The seroprevalence and mean titres were highest in the vaccinated cattle 3 months after vaccination. These then receded, however, 1% of vaccinated calves and 1.9% of vaccinated cows from the village without infected cattle were still seropositive on the complement-fixation test (CFT) 24 months after vaccination. Non-vaccinated seropositive animals were more likely to have aborted or had a stillbirth and were less likely to have produced a calf than were seronegative cows from the village containing infected animals. We concluded that strain 19 vaccine induced protection in Bali cattle and that this vaccine might play an important role in the control of bovine brucellosis in Timor.