A study of some infectious causes of reproductive disorders in cattle owned by resource-poor farmers in Gauteng Province, South Africa.

Two hundred and thirty-nine cattle from Gauteng Province in South Africa were tested for various pathogens causing reproductive diseases includingbovine viral diarrhoea/mucosal disease (BVD/MD) virus, infectious bovine rhinotracheitis/infectious pustular vulvovaginitis (IBR/IPV) virus, Neospora caninum and Brucella abortus usingvarious tests. For BVD/MD virus, 49.37% tested positive, 74.47% for IBR/IPV virus, 8.96% for Neospora caninum and 3.8% for Brucella abortus. The result for Brucella abortus is higher than the national average, possibly due to the small sample size. A high seroprevalence of antibodies to both BVD/MD virus and IBR/IPV virus was evident. These 2 viruses should be considered, in addition to Brucella abortus, when trying to establish causes of abortion in cattle. The clinical significance of Neospora caninum as a cause of abortion in Gauteng needs further investigation. One hundred and forty-three bulls were tested for Campylobacter fetus and Trichomonas fetus, and a low prevalence of 1.4% and 2.1% respectively was found in this study. The clinical implications of these findings are discussed.

Detection of the bovine viral diarrhoea/mucosal disease (BVD/MD) virus in tissues from aborted ruminant foetuses using immunohistochemistry.

Various tissues from aborted ruminant foetuses were collected, fixed in formalin and embedded in paraffin wax. Sections were made and exposed to a primary monoclonal antibody against the bovine viral diarrhoea/mucosal disease (BVD/MD) virus, and subsequently to a goat anti-mouse secondary antibody conjugated to horse radish peroxidase (HRP). Diaminobenzidine (DAB) was the substrate and it released a brown pigment in the tissues on reacting with the HRP in an immunohistochemistry (IHC) procedure. Of 27 aborted foetuses, an immunoperoxidase staining reaction was observed in 1 ovine and 5 bovine foetuses. The IHC procedure located BVD/MD viral antigen in a wide variety of foetal tissues including cerebral cortical neurons, the pseudostratified columnar epithelial cells lining the bronchi, alveolar lining cells and alveolar macrophages, hepatocytes, renal tubular lining cells and the Purkinje fibres in the myocardium.

Caprine vertebral osteomyelitis caused by Rhodococcus equi.

There have been reports of Rhodococcus equi infections in goats in Australia, America and India. In this study, R. equi was isolated from an inflamed vertebra in a Boer goat in South Africa. At autopsy, there was a purulent inflammatory reaction in the 1st cervical vertebra. Histopathologically, a neutrophilic infiltration was encountered in the bone. Aerobic culture of swabs collected from the abscesses yielded R. equi in pure culture that was identified on biochemical tests. R. equi has become important as the cause of an opportunistic infection in people suffering from HIV.

Toxicity of chloroform extract of prunus africana stem bark in rats: gross and histological lesions.

Chloroform extract of Prunus africana (Hook f. (Rosaceae) did not cause clinical signs or pathology in rats at daily oral doses of up to 1,000 mg/kg for 8 weeks. The extract caused marked clinical signs, organ damage and a 50% mortality rate at a dose of 3.3 g/kg for 6 days. The main lesions observed at this dose were marked centrilobular hepatocellular degeneration and necrosis, diffuse nephrosis, myocardial degeneration, lymphocytic necrosis and neuronal degeneration. The morphological damage in these tissues caused a corresponding rise in blood biochemical parameters namely, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, lactate dehydrogenase, creatine kinase and blood urea nitrogen. The target organs of toxicity of this extract are the liver, kidney and heart. Overt toxicity occurred only after the administration of multiple doses of 3.3 g/kg body weight. These findings confirm the suitability of this extract for therapeutic use, since the doses used in the therapy of prostate gland are much lower than those used in this study and would therefore not be expected to cause pathological changes.

Biochemical and haematological changes in rats administered an aqueous extract of Prunus africana stem-bark at various dosage levels.

An aqueous extract of Prunus africana (Hook. f.) Kalkm. (syn. Pygeum africanum) (Hook. f.) (Rosaceae) was administered daily at dosage rates of 10, 100 and 1,000 mg/kg body mass to randomized groups of Sprague Dawley rats. The extract caused a moderate rise in plasma alanine aminotransferase and creatine kinase mainly at rates of 1,000 mg/kg body mass, but it did not cause any significant variations in haematological parameters or in plasma levels of total proteins, albumin, aspartate aminotransferase, alkaline phosphatase and blood urea nitrogen at the dosage levels used. There were no overt clinical signs in any of the rats. It was concluded that the extract may contain components that are mildly toxic to the liver and heart of rats after repeated daily oral administrations of 1,000 mg/kg body mass.

Effect of an aqueous extract of Azadirachta indica on the immune response in mice.

Because of the very wide spectrum of infectious and non-infectious diseases for which preparations from Azadirachta indica are said to be efficacious, it was suspected that a general immunopotentiating ability could be part of the mechanisms by which it ameliorates so many disease conditions. Using the haemolytic plaque technique, an aqueous extract of Azadirachta indica stem bark was shown to enhance the immune response of BALB/C mice to sheep red blood cells in vivo.

A case of ovine lymphosarcoma in Kenya.

Ovine lymphosarcoma was diagnosed clinically in a 5-year-old Blackhead sheep in Kenya, and confirmed on blood smear, leukocyte count and macroscopic pathology. Four progeny of the ewe were examined. They were normal haematologically but 2 revealed bilaterally enlarged lymph nodes.

Effects of the extract of Spirostachys venenifera Pax on the immune response in mice.

The effects of the methanol extract of Spirostachys venenifera Pax (SVP) on the immune response in mice was investigated. Keyhole limpet haemocyanin (KLH) was the antigen. An enzyme linked immunosorbent assay (ELISA) was used to monitor serum antibody levels in mice exposed to various doses of SVP at a dosage of 0.1 mg/Kg. In mice in vivo, SVP caused a significant suppression of the immune response compared to control mice that received no SVP. A haemolytic plaque assay was used to monitor the effect of SVP on antibody producing B lymphocytes from the peritoneum and from the spleen in vitro. SVP caused a reduction in the number of plaque forming cells (PFC) at 0.1 ug/ml with peritoneal B cells. There was further reduction of PFC with higher doses of SVP. With the spleen B cells, clear reduction in PFC was seen only with the higher doses of SVP, from 1 ug/ml upwards to 100 ug/ml. The prospect of developing a new immunosuppressive agent from SVP is a welcome possibility that can add to the newer immunosuppressive agents with greater efficacy and less side effects in comparison to the traditional ones.

Arteriosclerosis and related lesions in rabbits.

Eleven female rabbits, mainly of the NZW breed, aged between 1 and 3.5 years, were examined post mortem. All had originated over the years 1982 to 1987 from the same rabbitry where they had been fed on pellets from the same manufacturer. Apart from one rabbit, all had a history of progressive loss of bodily condition and six of them had also been infertile. Grossly, most of them were emaciated and their arteries were hardened. In some, hepatopathy, nephropathy and pulmonary emphysema were evident. In one case, mummified foetuses were recovered from the abdominal cavity. Microscopically, degenerative changes and calcification were found in the walls of arteries, kidneys, lungs, hearts and ovaries.