The isolation and serology of Brucella melitensis in a flock of goats in central RSA.

Brucella melitensis biotype 1 was isolated in pure culture from the lungs, liver, spleen, kidney, stomach contents, abomasum and brain of an aborted caprine (Boer goat) foetus in the district of Cullinan near Pretoria. The 18 does and 1 ram in the flock of Boer goates were examined serologically by means of the complement fixation (CF) test, using Brucella abortus antigen. Six weeks later they were examined again, using B. abortus as well as B. melitensis biotype 1 antigens. No significant differences were found between the 2 CF tests using B. abortus antigen, or between the results obtained by using the B. abortus and B. melitensis antigens. Twelve goats, showing CF antibody titres, were slaughtered and examined bacteriologically. No relationship was found between the serological and bacteriological results.

Leptospirosis as a cause of "white spot" kidneys in South African pig abattoirs.

The incidence of isolation of Leptospira sp. from the kidneys of slaughter pigs with "white-spot" macroscopic lesions was determined. Histology and general bacteriology were performed. Leptospira pomona was isolated from 19/21 kidneys showing macroscopic lymphocytic lesions.

Valsiekte (falling disease): a nervous disorder in lambs suspected of being caused by the plant Chrysocoma tenuifolia.

A description is given of the clinical signs and pathological changes in 23 field cases of valsiekte from the Bethulie region of the Orange Free State, Republic of South Africa. The disease, which occurred almost exclusively in 2-4 month-old Dorper or Dorper cross-bred lambs, was characterized by protracted ataxia, paresis and high mortality. Microscopical changes were consistently found in the neurons and white matter along the entire length of the spinal cord, and rarely in the medulla oblongata. These changes included vacuolation and degeneration of neurons, mainly of the lateral and ventral horns in the spinal cord, and a status spongiosus which was most noticeable in the lateral and ventral tracts of the spinal cord. All affected lambs had access to the plant, Chrysocoma tenuifolia (bitterbos), but trials to reproduce the condition by dosing the plant, were not successful.

Chronic splenitis as a possible complicating factor in calves inoculated with an attenuated redwater vaccine.

In two consecutive years a total of 3810 calves were inoculated with the Onderstepoort redwater live-blood vaccine, containing attenuated strains of Babesia bigemina and Babesia bovis. Twenty calves died 8-13 days later due to B. bigemina-infection. Necropsies were performed on 19 of these animals. In 11 calves the spleen was distinctly smaller than normal and its morphology was distorted, and showed changes of chronic splenitis. Histological lesions in the spleens of 6 of the 11 calves are described. The potentiating effect of the splenic lesions to reduce the ability to contain the vaccine reaction, is discussed.

Isolation of Plasmodium circumflexum from wild guineafowl (Numida meleagris) and the experimental infection in domestic poultry.

A strain of Plasmodium circumflexum isolated from wild guineafowl was highly pathogenic to turkeys. Mortality in turkeys occurred in a biphasic pattern--at the peak of parasitaemia associated with severe anaemia and 7 to 18 days afer the peak associated with the presence of exoerythrocytic schizonts in the brain capillaries. In the acute cases the pathology findings were anaemia, icterus and splenomegaly; in the subacute cases severe splenomegaly, right ventricular hypertrophy and multifocal interstitial myocarditis.