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Biomedical subjects

W S Botha

Publications and source records attributed to W S Botha.

At least 19 recordsLinked to original sources
PubMed1989

Studies of encephalitozoonosis in vervet monkeys (Cercopithecus pygerythrus) orally inoculated with spores of Encephalitozoon cuniculi isolated from dogs (Canis familiaris).

Encephlitozoonosis was induced in 35 of 38 vervet monkeys (Cercopithecus pygerythrus). They were either directly (orally) inoculated with Encephlitozoon cuniculi or indirectly exposed to this protozoan parasite. Cell-culture-grown spores of E. cuniculi, isolated from the kidneys of dogs with natural, fatal disease, were administered orally to 29 of these monkeys. Another 5 were exposed in utero by orally infecting pregnant females, and 3 were exposed to horizontal infection by nursing infected infants. Only one was given an intravenous inoculation of spores. The disease was induced in non-gravid and late-pregnant adults, immunocompetent infants, and in infants that were immunologically compromised by parenteral steroid administration, as well as in one infant that was immunologically immature because of its premature birth. The effects of age, dosage, post-inoculation (PI) interval, passage level of the parasite in cell culture and immunological status of the host were correlated with macroscopical and microscopical lesions. The experimentally induced infection was confirmed either by reisolation of the parasite in cell culture or by observation of spores in tissue sections. Both confirmatory methods were supported by serological examination. Reisolation of the organism in primary cell culture prepared from kidneys usually resulted in more frequent isolates and larger yields of spores from infants than from adult vervets. Infection with E. cuniculi invariably induced subclinical disease. Based on histology, lesions were minimal to moderately severe, depending on age, PI interval, and immunological status of the host. Alimentary tract infections were seen histologically as early as three days PI. Subsequently, infections resulted in detectable lesions most consistently in the liver, kidneys and brain. Lesions in these organs were generally granulomatous and were similar to those found in canine encephalitozoonosis. In addition, multifocal interstitial pneumonitis and myocarditis as well as vasculitis and perivasculitis were seen in other tissues and organs. Infants had more severe and more widespread lesions than adults. Although lesions and spores were still present in the brain of one immunocompetent infant 36 weeks after initial infection, the disease in immunocompetent infants and adults is thought to be self-limiting. However, infection may persist. Immunological depression favoured increased growth and multiplication of the organism, and resulted in detection of more spores within inflammatory lesions as well as more intracellular colonies of the organism that were free of inflammatory reaction.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

The 'lung in shock' as a result of hypovolemic-traumatic shock in baboons.

The "lung in shock" syndrome is a constellation of early morphologic changes in the lung within 1 hour after polytrauma as indicated by human lung biopsies. A hypovolemic-traumatic (soft-tissue trauma together with bone fractures) baboon model with reinfusion was established to study these morphologic and associated pathophysiologic events. This model was developed in order to test the efficacy of therapeutic modalities in future studies. Nineteen baboons (eight sham, 11 shock) were anesthetized with spontaneous respiration while complete hemodynamic and blood gas monitoring was performed, along with light and electron microscopic studies of the lungs. Besides the usual shock-related hemodynamic disturbances and the metabolic acidosis, pathologic changes were found both on light and electron microscopy of the lungs but not on X-rays and measurements of blood oxygenation. In the shock group, morphologic evidence of endothelial and interstitial edema was associated with significant increases in lung weight. The fluid accumulation occurred in spite of careful control of pulmonary artery pressures during the study. More striking histologic findings were significant cellular infiltration of lung tissue, especially by leukocytes, showing evidence of degranulation. This baboon study, similar to studies undertaken in canines, shows that the hypovolemic (hemorrhagic) shock in association with trauma (fracture, soft-tissue trauma) causes ultrastructural morphologic changes that may precede potentially life-threatening functional changes in the lung.

Animals↗
PubMed1986

Observations on the pathology of experimental encephalitozoonosis in dogs.

Experimental transmission of canine encephalitozoonosis was effected by oral dosing of urine obtained from naturally diseased animals. Per os, intraperitoneal and intravenous routes were used to induce infection with tissue culture-grown Encephalitozoon spores which were initially isolated from the kidney of a dog with terminal disease. The infection was confirmed by a rise in the indirect immunofluorescent antibody titres, the lesions found in infected dogs and isolation of the parasite in tissue culture from an infected and immunosuppressed dog. The experimentally induced disease was invariably subclinical but the histopathological changes were similar although milder than those found in fatal natural disease. The kidney appears to be the target organ and chronic interstitial nephritis develops regularly.

Animals↗
PubMed1986

Evaluation of kidney function in dogs suffering from canine encephalitozoonosis by standard clinical pathological and radiopharmaceutical techniques.

Canine encephalitozoonosis can be responsible for a severe renal disease in dogs which may develop into progressive, irreversible kidney failure. Three pure-bred Boxer littermates with confirmed encephalitozoonosis were subjected to sequential clinical pathological tests and renal biopsies. The endogenous serum creatinine and urea levels showed an initial temporary reduction but later increased steadily. The phenolsulphonphthalein retention test confirmed this end-stage renal disease. Initial hyper-gamma globulinaemia showed a rapid decline. Urinalysis was an indicator of chronic renal disease and the kidney biopsies confirmed progressive irreversible kidney lesions. Evaluation of sequential tests are advocated for the setting of a prognosis. The radiopharmaceutical techniques employed proved to be sensitive indicators of renal dysfunction and a means of evaluating the function of the left and right kidney separately.

Animals↗
PubMed1985

[Subcutaneous fibrosarcoma in a lion (Panthera leo)].

A subcutaneous growth developed on the left side of a zoo lion. The growth enlarged over a period of 3 months. A diagnosis of fibrosarcoma was made on account of the history, clinical and histological examinations. The lion was killed 3 weeks after surgical removal of the tumour. The autopsy showed no evidence of metastases. A foreign body (wire) was discovered in the abdominal cavity but no association was found between the lesion caused by the wire and the malignancy.

Animals↗
PubMed1982

Effect of a high copper intake and different levels of molybdenum on the health of sheep.

Molybdenum at levels of 2, 20, 40, and 60 mg/kg dry matter was added to a sheep ration containing 82 copper and 3, 8 g sulphur per kg dry matter. At the 2 higher levels of molybdenum, a substantial accumulation of copper and molybdenum was observed in the kidney cortices of the South African Mutton Merinos (reported elsewhere). The effect of these treatments on the health of the sheep was investigated. Observations on the 3 molybdenum supplemented treatments were: Serum enzyme levels remained normal throughout the trial. No evidence of kidney damage due to treatment could be obtained from kidney clearance studies. No pronounced liver lesions were evident from histophathological evaluations. A significant increase in Periodic acid Shiff positive stained granules was observed in the cortical tubules of the kidneys at increased molybdenum intakes. However, this was considered to be of minimal physiological significance. It was concluded that molybdenum prevented liver damage due to excess copper and that copper and molybdenum which did accumulate in the kidneys were probably harmless and present in an unavailable form to the body or caused minimal morphological changes. No haemolytic crisis occurred in the sheep receiving no added molybdenum. However, their concentration of serum enzymes Aspartate transaminase and Lactate dehydrogenase increased throughout the 193 day trial. It is suggested that elevated levels of these enzymes may be unreliable indicators of an approaching haemolytic crisis in the Merino.

Animal Nutritional Physiological Phenomena↗
PubMed1981

An outbreak of African horsesickness in dogs.

Several dogs died from African horsesickness which was contracted by the consumption of uncooked meat from the carcase of a horse that had died from the disease. Respiratory embarrassment was the main clinical sign, while marked hydrothorax and pulmonary congestion and oedema were the major post mortem findings. Serotype 6 horsesickness virus was isolated from 2 of these dogs.

African Horse Sickness↗
PubMed1979

Pneumocystosis: a chronic respiratory distress syndrome in the dog.

Pneumonia caused by Pneumocystis carinii in two unrelated Miniature Dachshunds is reported. The clinical findings, gross- and histopathology and some diagnostic transmission and scanning electron microscopic features of the condition are described. Although pneumocystosis has been reported from a human and a domestic goat in the Republic of South Africa, these are probably the first reported cases of the canine disease in this country.

Animals↗
PubMed1979

The prevalence of Encephalitozoon antibodies in dogs and an evaluation of the indirect fluorescent antibody test.

Fifteen dogs which were serologically negative to the IFA test against Encephalitozoon developed antibodies in their sera following experimental infection. Six other dogs which were not tested prior to infection had titres to Encephalitozoon after experimental infection. In a sequential study in four dogs, antibodies first appeared between 32 and 39 days after infection. These results show that the IFA test would be suitable for epidemiological studies. Fifty serum samples collected from two kennels in which encephalitozoonosis had been confirmed showed an IFA test positive prevalence rate of 70%. In 220 serum samples submitted for various clinial pathological examinations the prevalence rate of antibodies to Ebcephalitozoon was 18%.

Animals↗
PubMed1979

Canine encephalitozoonosis in South Africa.

Clinical, clinicopathological macroscopical and histopathological findings, as well as electron microscopic and cultural confirmation, in twelve natural cases of canine encephalitozoonosis are described, eleven of these under one year of age. Nervous symptoms, including blindness, retarded growth rate and nephritis are prominent clinical signs. The macroscopic findings and histopathology proved of great help in the diagnosis of the disease even in chronic cases. The organism was cultured and some distinguishing electron microscopical features between Encephalitozoon and Nosema are discussed. A transmission experiment confirmed the diagnosis. The results are compared with the reported cases in dogs and Blue Foxes (Alopex lagopus).

Animals↗
PubMed1979

Canine encephalitozoonosis in kennels and the isolation of Encephalitozoon in tissue culture.

The protozoan Encephalitozoon was isolated in primary kidney cultures from dogs originating from three separate outbreaks of encephalitozoonosis in kennels. The disease was characterized by a fading syndrome in young puppies with nervous signs developing in some cases. It was not possible to reproduce the clinical disease with cultured organisms in either normal dogs or dogs immunosuppressed with methylprednisolone. The organisms were, however, reisolated in primary culture from two immunosuppressed dogs but not from other experimentally infected dogs. The freezing of Encephalitozoon organisms in liquid nitrogen is described.

Animals↗
PubMed1979

Parvovirus as a cause of enteritis and myocarditis in puppies.

A gastro-enteritis syndrome mimicking feline panleukopaenia was diagnosed in young dogs in the Republic of South Africa. Parvovirus was demonstrated by electron microscopy in the faeces of these animals. In addition an acutely fatal, acute to sub-acute non-purulent interstitial myocarditis occurred in pups in the same area. Histopathologically large basophilic intranuclear inclusion bodies were seen in the myocardium of these cases. The two syndromes generally occurred separately, but in two cases were found in the same individuals. The literature on the subject is briefly reviewed and the clinical and pathological findings in these outbreaks are reported.

Animals↗
PubMed1978

Muscle irritation caused by different products containing oxytetracycline.

Muscle irritation studies were done in rabbits using 9 different commercial products. Eight products had propylene glycol and 1 had polyvinylpyrrolidone as a vehicle. Macroscopical examination 3,6 and 10 days after intramuscular injection indicated that the irritation caused by the 8 products with propylene glycol as a vehicle were very similar. The product with polyvinylpyrrolidone caused much less damage and healing took place more quickly. Saline used as a control caused no tissue damage.

Animals↗