Observations on bilharziasis of domestic ruminants in South Africa

Bilharziasis of 100 sheep and 14 cattle caused by Schistosoma mattheei Veglia & Le Roux, 1929, was studied in detail from the histopathological aspect. The ovine cases included natural as well as experimentally infested animals. The most significant changes resulted from the presence of schistosome ova and the dead schistosomes in the branches of the intrahepatic portal vein. The host reaction to the ova is of a granulomatous nature which is interpreted as a type of delayed hypersensitivity reaction. In a few cases there was an even more marked sensitivity superimposed on this. It was characterized by concentrations of eosinophiles around miracidial-containing ova as well as shells of ova present in the centre of mature granulomas. This was accompanied by necrosis of adjacent liver cord cells and necrosis of masses of eosinophiles. This appears to be analogous to the toxaemic form of human bilharziasis. In both sheep and cattle, particularly the latter, the host response to dead adult schistosomes in the intrahepatic branches of the portal vein was striking. The initial thrombosis was followed by a granulomatous response to remove the parasite, and a localized lymphoid proliferation which destroyed the wall of the vein and remained after the schistosome had been removed. The Hoeppli phenomenon occurred in response to ova in both sheep and cattle; being more pronounced and more frequently present in cattle. The conclusion is drawn by the authors that cattle are less affected by bilharziasis than sheep and goats.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

Clinicopathological study on experimental Trypanosoma brucei infections in horses. Part 2. Histopathological findings in the nervous system and other organs of treated and untreated horses reacting to nagana

A detailed description of the histopathology of the nervous system and a brief account of lesions in visceral and other organs of six horses experimentally infected with Trypanosoma brucei Plimmer & Bradford, 1899 is given. Attempts to produce a chronic form of nagana in three horses by subcurative medications with Antrypol and Berenil were successful. The chronicity period was extended to 130 days in one and to approximately 9 months in the other two horses. The data on the histological findings on the three horses are listed in tabular form. The lesions in the central nervous system were characterized by a severe pleocytosis of the meninges, an extensive subpial gliosis corresponding in severity to the involvement of the overlying leptomeninges, segmental demyelination of optic tracts and some other areas of white matter as well as grey matter and extensive perivascular cuffing with lymphocytes, plasmocytes, large mononuclear and Mott cells in this order of descending frequency. Comparison between lesions of the acute form of human sleeping sickness and those of the experimentally produced chronic form of equine nagana revealed that points of similarity are far greater than those of dissimilarity. The latter include a lymphophagocytosis in the meninges and brain of man, a higher incidence of Mott cells in the meninges of horses and the penetration of trypanosomes in the brain of man which was not seen at this site in horses. With the exception of the pituitary of one horse, lesions of the nervous system of the remaining three horses were not striking. Histological changes in the visceral and other organs were neither pathognomonic nor of uniform occurrence.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

Clinicopathological study on experimental Trypanosoma brucei infections in horses. Part 1. Development of clinically recognizable nervous symptoms in nagana-infected horses treated with subcurative doses of Antrypol and Berenil

Studies on the pathogenesis and symptomatology of the acute and chronic forms of human sleeping sickness and those appearing in equine nagana caused by Trypanosoma brucei Plimmer & Bradford, 1899 are given. In man the initial invasion of the blood stream and lymph nodes by either T. rhodesiense Stephens & Fantham, 1910 or T. gambiense Dutton, 1902 is invariably followed by parasites entering the cerebrospinal fluid and eventually extending to the brain and producing symptoms of meningo-encephalitis. In horses the invasion of the blood stream and lymph nodes by T. brucei results in the development of a peracute, acute or chronic disease which nearly always terminates fatally without clinical evidence of an involvement of the central nervous system. Consideration of the relatively short reaction periods of 2 to 3 months in T. brucei infections when compared with those of 9 months to several years in human trypanosomiasis, suggested that prolongation of the course of nagana in horses by subcurative treatments with Antrypol and Berenil would allow the parasite sufficient time to enter the cerebrospinal fluid and then to exert its pathogenicity on the central nervous system. It was found that such treatments resulted both in the extension of the course and in the appearance of nervous symptoms in two of the five treated horses. The involvement of the central nervous system was confirmed at necropsy by a mild hydrocephalus, oedema of the brain, thickening of the meninges and the detection of T. brucei in the cerebrospinal fluid. Evidence is presented that in common with T. rhodesiense and T. gambiense, T. brucei under certain conditions exerts its invasive potential for the cerebrospinal fluid.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

Cytauxzoonosis in a giraffe (Giraffa camelopardalis (Linnaeus, 1758)) in Zululand

Cytauxzoonosis is reported for the first time in a giraffe [Giraffa camelopardalis (Linnaeus, 1758)] that died naturally of the disease. Both histiotropic and erythrocytic parasites were found. The animal was very anaemic and had marked haemoglobinuria. The most significant lesions were disseminated foci of haemorrhage and necrosis, especially in the liver, spleen and abomasum. Multiple haemorrhages also occurred on both pleura and peritoneum, within and on the entire gastro-intestinal tract, on the surface of the kidneys, subepicardially and in the urinary bladder. Very enlarged and even multinuclear cells heavily parasitized by schizonts were encountered in the lesions.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.

Observations on the pathogenesis of bovine and antelope strains of Besnoitia besnoiti (Marotel, 1912) infection in cattle and rabbits

Histopathological studies were made on cattle and rabbits, artificially infected with either proliferative organisms of low and high passage level bovine strains of Besnoitia besnoiti (Marotel, 1912) grown in tissue culture and in rabbits, or cyst organisms from a natural bovine case of besnoitiosis. Rabbits similarly infected with either proliferative organisms of a low level rabbit-passaged blue wildebeest [Connochaetes taurinus (Burchell, 1823)] strain or cyst organisms from naturally infected blue wildebeest and impala [Aepyceros melampus (Lichtenstein, 1812)] were likewise used for comparative studies. Degenerative and necrotic vascular lesions, vasculitis and thrombosis, mainly of the medium and smaller veins and some arteries, were the most outstanding changes in the acute stages of the disease. These changes coincided with the parasitization of certain cells in the vessels such as the endothelium, where the organisms proliferate before the onset of the cystic stage. These basic lesions were responsible for oedema, degenerative changes and even infarction, particularly in the testes and skin. A histiocytic reaction and mild eosinophil infiltration were some of the other characteristic features. The cystic stage in cattle apparently developed in enlarged histiocytes, which were recognizable 11 days after infection. These host cells became multinuclear and seemed to be responsible for the production of the cyst wall. The cysts reached maturity 71 days after infection. Reactions to cysts apparently commenced before any degenerative changes in the organisms were detectable and could have been preceded by such changes in the cyst wall. The antelope strains of B. besnoiti were only very mildly pathogenic to rabbits, but passage during the acute stage of the disease in this host increased the pathogenicity considerably. Rabbits which were infected with bovine strains developed severe testicular and skin lesions, but these lesions were either absent or relatively mild in rabbits infected with antelope strains. In the latter, lesions were usually confined to internal tissues and organs such as the myocardium, gut and lungs and, more rarely, even in the adrenal, liver, kidneys and urinary bladder. However, cysts were rarely encountered in both these groups.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..mn201

Immunization against bovine besnoitiosis with a live vaccine prepared from a blue wildebeest strain of Besnoitia besnoiti grown in cell cultures. 1. Studies on rabbits

The immunizing potency of a live vaccine prepared from a strain of Besnoitia besnoiti isolated from blue wildebeest and stored frozen as a low passage stabilate was studied in adult male rabbits. The vaccine consisted of parasites that were grown in primary lamb kidney or an established line of green monkey kidney cell (Vero) cultures and suspended in serum-free Hanks' or Eagle's medium respectively. Freshly prepared doses containing from 1 x 10 to 2 x 10⁵ parasites of the 14th to 34th culture passages were injected subcutaneously. The blue wildebeest strain was pathogenic in rabbits at all the dosage levels tested and 24, 6 per cent died as result of vaccination. The survivors were challenged one to six months after vaccination by subcutaneous inoculation with a bovine strain of B. besnoiti grown in lamb or Vero cells from a low passage level frozen stabilate. Immunized rabbits were protected against challenge doses that were 10 to 100 000 times greater than those of the vaccine. Immunized rabbits did not show any evidence of infection, whereas all the controls developed typical reactions (patent parasitaemia, scrotal oedema, orchitis) and 58 per cent died. It was therefore not possible to calculate an ID₅₀ for vaccinated and control rabbits in this investigation, but one experiment revealed that more than 5 logs of protection had been induced by the vaccine. Rabbits injected with Vero cells only were not protectedThe 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

Observations on the pathology of bilharziasis and other parasitic infestations of Hippopotamus amphibius Linnaeus, 1758, from the Kruger National Park

Necropsies were conducted on 100 hippopotami during the winter of 1964 in an area of the Kruger National Park where the continuous drought, over a period of three years, had reduced food supplies to a very low level. Systematic observations revealed the presence of 12 helminth species belonging to the classes Trematoda, Cestoda and Nematoda, a blood sucking annalid, a single case of Hepatocystis hippopotami infection as well as a specifically unidentified unicellular organism in the liver and uterus. The latter is believed to have been a coccidium, the bodies observed being unsporulated oocysts having a spinous and striated wall. A summary of the significant pathological changes produced by Schistosoma hippopotami, Fasciola nyanzae and Echinococcus granulosa africanus is presented in Table 1. The pathogenicity of the remaining parasites appears to have been mild or insignificant. The most striking observations were the high incidence and unusual distribution of S. hippopotami, and the pathognomonic cardiovascular lesions in response to adult parasites. These were characterized by the formation of a pseudo-intima in branches of the pulmonary artery and various veins and a pseudoendocardium within the heart. Significant numbers of S. hippopotami were found in the heart and all major blood vessels. Lesions, encountered in the systemic and visceral circulation, were most prevalent in the heart, pulmonary artery branches, posterior vena cava, venae hepaticae and portal veins. Taxonomic affinities of S. hippopotami are presented. 587 The unusual distribution of the adults, the very low degree of ovigenesis and the relatively high number of free and encapsulated schistosome ova in the adrenal cortex, medulla and vein as compared to those of the lung, liver, alimentary tract and pancreas, as observed during winter, cause doubt whether the hippopotamus is a normal host of S. hippopotami. Suggestions made that the hippopotamus could be an aberrant host would require proof that ovigenesis is not subject to a seasonal periodicity, and evidence for the existence of an alternative normal host.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

The pathology of Cordophilus sagittus (v. Linstow, 1907) infestation in the kudu [Tragelaphus Strepsiceros (Pallas, 1766)], bushbuck [ Tragelaphus scriptus (Pallas, 1766)] and African buffalo [Syncerus caffer (Sparrman, 1779)] in South Africa

1. An account is given of the lesions caused by Cordophilus sagittus infestations of an African buffalo, a bushbuck and 18 kudus. 2. The distribution of adult parasites and the host response in the kudu are given in detail. 3. Adult worms appeared most frequently in medium-sized and small branches of the pulmonary arteries, less frequently in coronary veins and only occasionally in the right ventricle. 4. Aneurysms filled with parasites and showing a rather remarkable proliferative intimal reaction frequently appeared in the coronary veins and in the medium-sized and small branches of the pulmonary arteries. 5. Non-aneurysmic segments of the pulmonary arteries also reacted to the parasitic infestation. This manifestation might be summed up as a "proliferative polypoid villose verminous endarteritis". 6. Attention is drawn to the close resemblance between this manifestation and certain types of reactions in the pulmonary arterial tree of dogs caused by another filarial worm, Dirofilaria immitis. 7. The possible significance of the lesions described above as a health problem in wild ruminants is discussed. 8. Knowledge on the incidence of C. sagittus infestation in cattle and buffalo appears to be restricted to single cases in each. Careful examination of the myocardium of these species when the opportunity avails itself may yet reveal a higher morbidity rate. 9. It is proposed that the derivative from the generic namely, "Cordophilosis " be used for the disease.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

Observations on Besnoitia cysts in the cardiovascular system of some wild antelopes and domestic cattle

Following a previous preliminary note on besnoitiosis in South African impala, blue wildebeest and kudu, more details are reported on this disease in game. Particular attention is given to the distribution of the cysts and the associated macro and histopathological changes. A comparative study with besnoitiosis in five bovines is outlined. Some of the more salient findings of the investigation are the following: the apparent absence of clinical signs of the disease in the antelopes examined; the almost exclusive confinement of the cysts to the cardiovascular system of antelopes; the marked incidence of cysts in the subcutaneous lymphatics of impala and in the peripheral veins of the limbs of cattle and antelopes, the head of cattle and the jugular veins of antelopes. The significance of Besnoitia cysts within the vessels is discussed in relation to the pathogenesis and transmission of the disease. An incidental finding recorded is that of the nymphae of a specifically unidentified pentastome within the cardiovascular system and liver of blue wildebeest and kudu.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

Observations on the pathology of canine microsporidiosis

The available literature on canine microsporidiosis indicates that this disease, primarily of young dogs, is a distinct clinicopathological entity. It has been confused with canine distemper and rabies, and must be differentiated from toxoplasmosis. Information available on the spectrum of pathological change associated with this disease is incomplete but a distinct pattern emerges from a study of the reports. The aetiological agent appears to have a predilection for the central nervous system and kidneys, but other tissues and organs, and especially the liver, may also be infected. Vasculitis and perivasculitis, which may include fibrinoid necrosis, seem to be a basic lesion. Cellular inflammation ranges from polymorphonuclear leukocyte infiltration in areas of necrosis to focal granulomas. There may be no cellular reaction to compact groups of organisms. Histopathological and ultrastructural studies of this case augment our knowledge of the pathological changes seen with canine microsporidiosis.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