Electron microscopy of Cowdria (Rickettsia) ruminantium (Cowdry, 1926) in the endothelial cells of the vertebrate host

The ultrastructure of Cowdria ruminantium was studied in thin sections of choroid plexus from experimentally infected sheep. Glutaraldehyde fixation and osmium tetroxide postfixation were used. The organism developed within the confines of a membrane-bound vacuole in the cytoplasm of endothelial cells. Four different forms, or particles, of the organism could be identified: small, intermediate, large and very large or giant forms. The various forms differed not only in size but also in the appearance and distribution of the nucleoid and "cytoplasmic" material within their inner structure. Within any one vacuole, in the host cell cytoplasm, the organisms were of the same form or type. Multiplication of the organism took place mainly by binary fission of the small and intermediate forms. Infrequent evidence was found that reproduction may also take place by the process of multiple budding and endosporulation. Small forms of the organism were embedded in a well developed matrix. Small and large forms were seen extracellularly, lying free in the lumen of blood vessels. Rarely small forms were seen in vacuoles in the cytoplasm of monocytes. The taxonomic position of C. ruminantium is discussed.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.

Bluetongue virus as a cause of hydranencephaly in cattle

Hydranencephaly was produced in a foetus and a calf by intra-uterine infection with an attenuated Type 10 bluetongue virus. Laparotomy was performed on the respective dams and the foetust:s, respectively 126 days and 138 days old, were inoculated intramuscularly through the uterine wall with 1 ml of a virus suspension containing 5 x 10³ tissue culture infective doses. The younger foetus was aborted on Day 262, while the other one was born alive on Day 273. Both foetuses showed marked hydranencephaly.The articles have been scanned in colour with a HP scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to final presentyation PDF-Format

Amaurosis in sheep resulting from treatment with rafoxanide

Amaurosis occurred in sheep on various farms in the Republic of South Africa after treatment with rafoxanide. Histopathological examination revealed a status spongiosus of varying severity in the central nervous system in all the cases, having a predilection for certain areas such as the periventricular area of the lateral ventricles, optic tracts, lateral geniculates and optic fasciculi. The retina was the only ocular tissue affected and lesions observed in the retina included necrosis of nerve cells in the ganglionic layer. In chronic cases of amaurosis this layer showed a complete absence of nerve cells. The possible pathogenesis of the lesions and their differentiation from those found in certain plant toxicoses are discussed.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

The occurrence and pathology of chlamydiosis in domestic and laboratory animals : a review

The literature on the various disease syndromes caused by chlamydia in domestic and laboratory animals is summarized. A review of the pathological lesions which characterize these diseases is presented and the pathogenesis of chlamydiosis is briefly discussed. Some aspects of unpublished findings on the occurrence of intestinal, kidney and genital lesions in natural and experimental cases of chlamydiosis in cattle and sheep, abortions and conjunctivitis in horses in South Africa are recorded.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acroabt XI was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Pneumocystosis in a domestic goat

A fatal case of an infection by the parasite, Pneumocystis carinii Delanoë & Delanoë, 1914, is described in a young domestic goat. The disease was manifested as a severe diffuse interstitial pneumonitis accompanied by filling of the alveolar air spaces by large numbers of organisms. Light and electron microscopic studies revealed the parasite to be identical to previously described cases in man and other animals. This is apparently the first case recognized in an animal in Africa.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Studies on the pathology of heartwater Cowdria (Rickettsia) ruminantium, Cowdry, 1926 I. Neuropathological changes

The most significant pathological changes in the central nervous system of 27 cases of heartwater are described. In addition to leucostasis and cell infiltration in the perivascular and subarachnoid spaces described previously, the following changes were noticed:- Swollen axis-cylinders, microcavitation and focal necrosis of the cerebellar cortex; degenerative and necrotic changes in the neuroglia accompanied by the formation of P.A.S. positive intracytoplasmic granules and globules; the accumulation of P.A.S. positive globules in the V.R. spaces; choriomeningeal oedema and fibrinous choriomeningitis; haemorrhages, oedema and vascular changes. Evidence is submitted in favour of the perivascular globules being proteinaceous and of glial origin.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Maldronksiekte in cattle : a neuronopathy caused by Solanum kwebense N.E. Br.

A neurological disease of cattle (maldronksiekte), occurring in a localized area of the Northern Transvaal, was experimentally reproduced by feeding Solanum kwebense plants to cattle. The disease is characterized by temporary loss of balance and transient epileptiform seizures precipitated by a variety of stimuli, such as exercise, handling (dipping, loading, etc.) and fright. When not disturbed, most affected animals appear to be completely normal. The most conspicuous histopathological lesion is a neuronopathy manifested by vacuolar degeneration and eventual necrosis of neurones, particularly of the Purkinje cells in the cerebellum. An atrophy of the cerebellar cortex is seen grossly. The history, clinical signs and experimental reproduction of the disease, as well as the pathology of 4 experimental and 18 natural cases, are described.The articles have been scanned in colour with a HP scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to final presentyation PDF-Format

Herpes nodules in the lung of the African elephant, Loxodonta africana (Blumenbach, 1797)

Lymphoid nodules associated with Cowdry Type A intranuclear inclusions in epithelial and syncytial cells were found in the lungs of 74% of 50 African elephants in the Kruger National Park. Subsequent studies proved these were caused by a herpes virus (Erasmus, McCully, Pienaar, Young, Pieterse & Els, 1971). The disease appears to be subclinical or latent. This virus, in common with other herpes viruses, might be more pathogenic in some other host. The pathogenesis of the lymphoid nodules and the various stages of their formation are given and the detailed characteristics are illustrated.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Lesions in sheep skeletal and oesophageal muscle in vermeersiekte (Geigeria ornativa O. Hoffm. poisoning)

Vermeersiekte in sheep, which is characterized clinically by vomition of ruminal contents, often accompanied by stiffness or paralysis, is caused by various plant species of the genus Geigeria. A histopathological study of the skeletal and oesophageal muscles of three experimental and three natural ovine cases revealed lesions in every case. In paraffin sections examined by light microscopy, vacuolation of focal groups of muscle fibres was seen. The sarcoplasm in the vicinity of the vacuoles was hyalinized and single or multiple centrally displaced sarcolemmal nuclei occurred in the vacuoles. A variation in the size of muscle fibres in these foci was seen in the more chronic experimental cases. Small "atrophic" hyalinized fibres with centralization and proliferation of sarcolemmal nuclei were encountered. Electron micrographs revealed that the vacuoles in the sarcoplasm resulted from focal degeneration of myofibrils in otherwise intact muscle fibres. The thick myofilaments disappeared first, causing dissolution of the A-band in affected myofibrils. Shredding of the remaining thin filaments eventually lead to the complete destruction of myofibrils and the appearance in the fibre of irregular areas of fine granular material, containing remnants of myofilaments, Z-band material and swollen vacuolated mitochondria. Due to excessive loss of myofibrils the diameter of some muscle fibres was reduced.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Experimental studies with Strongyloides papillosus in goats

Unusual clinical and pathological observations in the field in goats and sheep suffering from Strongyloides papillosus infection prompted experimental work on this parasite. Goats were infected percutaneously with either single or multiple, low or high levels of S. papillosus. Young goats up to 12 months of age were found to be the most susceptible. Some animals, however, showed substantial resistance to infective doses. Clinical signs included transient diarrhoea, misshapen, elongated faecal pellets terminally, dehydration, anorexia, cachexia, gnashing of teeth, foaming at the mouth, anaemia and nervous signs such as ataxia, a wide-based stance, stupor and nystagmus. A 'pushing syndrome' was seen in 22 % of the animals. The pathological changes are described and included enteritis, status spongiosus in the brain, hepatosis leading to rupture of the liver, nephrosis, pulmonary oedema, interstitial pneumonia and pneumonia. About 6 % of the goats died acutely from fatal hepatic rupture. The development of an acquired immunity was determined. The immunity elicited an allergic skin reaction at the application site of larvae or injection sites of larval metabolites. This immunity, however, could be breached by large doses of larvae. The most profound clinicopathological changes induced by the parasites were an anaemia (most pronounced in the young goats) and hypophosphataemia. Trace element analyses provided evidence of Cu, Mn and possibly Se deficiencies in some goats.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201