A passive haemagglutination test for detection of antibodies against Mycoplasma mycoides subsp. mycoides using glutaraldehyde-fixed sheep erythrocytes.

A simple passive haemagglutination test using the microtitre technique was developed for the detection of antibodies against Mycoplasma mycoides subsp. mycoides infection in cattle. Of the four different concentrations (0.1, 0.2, 0.25 and 0.5%) of glutaraldehyde used for the fixation of sheep erythrocytes, antigens prepared with erythrocytes fixed with 0.2 and 0.25% concentrations of glutaraldehyde gave the best results. The test was found to be very practical, sensitive specific and reproducible. It also compares favourably with the complement fixation test.

Immunodepressive effects of trypanosomal infection in cattle immunized against contagious bovine pleuropneumonia.

Groups of cattle infected singly with Trypanosoma vivax and T. congolense and, with a combination of T. vivax and T. congolense, were vaccinated against contagious bovine pleuropneumonia (CBPP) 6 weeks before or after infection. All animals were revaccinated 12 weeks after primary vaccination. The primary antibody responses in cattle vaccinated 6 weeks after infection with T. vivax and a combination of T. vivax plus T. congolense were slightly depressed in contrast to other groups which were similar in their response to the control group. Although secondary antibody responses developed in all infected groups, with a delay in those infected with T. congolense, they did not reach the levels of the controls. In spite of the slight depression in antibody responses, however, 50% of the vaccinated trypanosomal animals contracted CBPP on exposure to experimental infection while the vaccinated controls were immune. It is suggested that the protective immunity to CBPP engendered by vaccination is impaired during infection with African trypanosomes and that the level of antibody response to CBPP vaccination in trypanosomal animals does not reflect the degree of immunodepression. The importance of trypanosomiasis control in ensuring success of vaccination campaigns against CBPP is discussed.

Detection of antibody against Mycoplasma mycoides subsp mycoides in cattle by an enzyme-linked immunosorbent assay.

The results of an enzyme-linked immunosorbent assay (ELISA) For the detection of antibody against Mycoplasma mycoides subsp mycoides are presented. Antibody was detected in the sera of cattle at least 19 months after recovery from an infection and at least 23 months after vaccination. Almost half the sera of some animals in an area of Nigera where contagious bovine pleuropneumonia is enzootic contained antibody. Antibody was rarely detected when the same sera were examined by other established serological tests, emphasising the sensitivity of the ELISA.

The T1 vaccine used in the control of contagious bovine pleuropneumonia in Nigeria.

A lyophilised T1 vaccine was produced by direct lyophilisation of a 72-hour broth culture to which 10% sterile sucrose solution was added. Each vial contained 2 ml to make a total of 10 doses when reconstituted. Each ml of the product contained an average of 109 colony forming units of the organism. When injected at the tip of the tail or subcutaneously behind the shoulder of 2,000 zebu and 1,0000 Ndama cattle, no outward reactions were observed. 12 zebu cattle were vaccinated and challenged 6 months later by direct contact with artificially infected cattle for 4 months. All the animals were completely protected against the disease.

In vitro antimicrobial sensitivity of Mycoplasmas isolated from the bovine genital tract.

The in vitro antimicrobial sensitivity of 14 mycoplasma and 13 ureaplasma strains isolated from the genital tracts of bulls was examined. It was found that at relatively low concentrations, tetracycline, declomycin and tylosin were lethal to both types of organisms. Lincospectin, berenil, streptomycin and erythromycin were lethal to mycoplasmas but were only inhibitory to the ureaplasma strains at the same concentrations. Polymyxin B and novobiocin were ineffective at the levels tested.

The recovery of Mycoplasmas from the genital tracts of bulls in artificial breeding units in Ontarïo.

One hundred and thirty-two penial-preputial swabbings, 140 raw and 42 processed semen samples were cultured for mycoplasmas. Mycoplasma or acholeplasma were recovered from 87, 32 and one respectively, while ureaplasmas were recovered from 46, 34 and six respectively.