The Onderstepoort journal of veterinary research.
Publisher:
Union Of South Africa. Department Of Agricultural Technical Services. Durbanville, Cape Town, South Africa : AOSIS Publishing
Frequency: Quarterly
Country: South Africa
Language: English
Author(s):
South Africa. Division of Veterinary Services.
Start Year:1951 -
ISSN:
0030-2465 (Print)
2219-0635 (Electronic)
0030-2465 (Linking)
2219-0635 (Electronic)
0030-2465 (Linking)
Impact Factor
2.7
2022
| NLM ID: | 0401107 |
| (DNLM): | O06760000(s) |
| (OCoLC): | 01761252 |
| Coden: | OJVRAZ |
| Classification: | W1 ON108 |
Scanning electron and light microscopy of the mucosa of the equine ileocaecal junction. The ileocaecal junction mucosal surface morphology of 5 horses and 1 donkey was examined using scanning electron microscopy and light microscopy. Based on differences in surface morphology, the junction could be divided into 4 distinct regions. The distal extremity of the ileum was characterized by the presence of typical finger-like villi followed by a narrow zone displaying short, stubby villi which gradually merged into a 3rd region representing the true transitional zone between the small and large intestine. In this region the villi fused, forming low ridges arranged in circular, semi-cir...
The transovarial transmission of Babesia caballi by Hyalomma truncatum. Babesia caballi, isolated from a horse that originated from South West Africa/Namibia, was transmitted transovarially by adult Hyalomma truncatum. B. caballi proved to be highly infective for adult H. truncatum. Forty-five per cent of ticks feeding on a reacting animal with an extremely low parasitaemia became infected. In spite of a low parasitaemia, the ticks were severely affected by the parasite. Seventy per cent of the infected ticks either died during oviposition or after laying only a few eggs. The features of the infection in horses were: a prepatent period of 10 days, very low parasit...
Adverse effects of a proposed equine sublethal endotoxin model. Commercially available Escherichia coli 055: B5 lipopolysaccharide was administered intravenously experimentally at a dosage of 10 micrograms/kg to 2 horses. Various clinical and clinico-pathological parameters were monitored before and after the endotoxin administration. Because of a hopeless prognosis, and for humane reasons, euthanasia was applied on both horses 6 h after administration. Values recorded for the different parameters, including the blood lactate level, were consistent with a lethal condition. It would appear that an intravenous dose of 10 micrograms/kg of endotoxin is potenti...
Leukoencephalomalacia in a horse induced by fumonisin B1 isolated from Fusarium moniliforme. Each of two horses was dosed by stomach tube with culture material on maize of Fusarium moniliforme MRC 826. One horse developed severe hepatosis and mild oedema of the brain after 6 doses of 2.5 g of culture material/kg body mass/day in 7 days. The second horse, in a similar experiment but at a dosage rate of 1.25 g/kg/day, developed mild hepatosis and moderate oedema of the brain. In both animals the brain oedema was particularly noticeable in the medulla oblongata. The mycotoxin fumonisin B1 was extracted and purified from the culture material of F. moniliforme MRC, 826 which contained appr...
Fasciola in horses in the Republic of South Africa: a single natural case of Fasciola hepatica and the failure to infest ten horses either with F. hepatica or Fasciola gigantica. The faeces of 11 horses were examined for Fasciola spp. eggs. One of them was positive for Fasciola hepatica, a finding which was confirmed post-mortem. The 10 negative horses were subsequently infested with either F. hepatica or Fasciola gigantica, each animal receiving orally from 500-9,500 metacercariae. No clinical signs were observed and no fluke eggs were detected in the faeces, and neither immature nor adult Fasciola worms were recovered from the horses slaughtered 16-26 weeks post-infestation with F. hepatica and 28-34 weeks post-infestation with F. gigantica, respectively. The results...
An investigation into alternative methods for the serodiagnosis of dourine. The complement fixation test (CFT), indirect fluorescent antibody test (IFAT), card agglutination test for trypanosomiasis (CATT) and enzyme-linked immunosorbent assay (ELISA) were compared in their application to the serological diagnosis of Trypanosoma equiperdum infection in 43 horses. The CFT remains a reliable test for dourine, especially in countries where other members of the subgenus Trypanozoon do not occur. The IFAT is a good 'back-up' test, but, requiring skilled operators it has the disadvantage of making it labour intensive, and interpretation of results subjective. This makes it ...
Isolation of pure Babesia equi and Babesia caballi organisms in splenectomized horses from endemic areas in South Africa. Both Babesia equi and Babesia caballi are endemic in large parts of South Africa. Attempts were made to obtain pure local isolates of both B. equi and B. caballi for the purpose of developing serological tests to study the epidemiology of equine babesiosis in this country. The indirect fluorescent antibody test was used to screen horses for B. equi and B. caballi in an endemic area. Seven horses and 3 donkeys between 3 and 36 months of age that tested negative were subsequently splenectomized. The splenectomy operation was performed through the abdominal approach. A 100% survival rate was achi...
The transstadial transmission of Babesia caballi by Rhipicephalus evertsi evertsi. Rhipicephalus evertsi evertsi larvae were fed on the ears of rabbits. Seven days after larval infestation, unfed, newly moulted nymphae were manually removed to infest a splenectomized donkey showing a patent Babesia caballi infection. Engorged nymphae were collected from the donkey and the ensuing adult ticks were placed on a susceptible horse. The horse contracted a B. caballi infection showing a prepatent period of 19 days after tick infestation. A very low parasitaemia, (highest score 2), which was patent for only 10 days, was recorded. The lowest packed cell volume recorded was 16%.
An investigation into the clinical pathological changes and serological response in horses experimentally infected with Babesia equi and Babesia caballi. Serologically negative horses, as determined with the indirect fluorescent antibody test (IFA), were infected with Babesia equi and 60 days later with Babesia caballi. The only clinical signs of disease observed in these animals were a febrile reaction and slight icterus. Haematological changes included a drop in haematocrit and haemoglobin concentration, as well as lowered platelet counts. The serum concentrations of albumin, iron and phosphorus were lowered. Mildly elevated serum bilirubin and fibrinogen concentrations were observed. Antibody titres were determined with the IFA and complemen...
The isolation of Leptospira interrogans serovar pomona and related serological findings associated with a mixed farming unit in the Transvaal. This is the first known isolation in the Republic of South Africa (RSA) of the serovar pomona from the organs of porcine foetuses as well as from the renal lymph nodes of slaughter pigs showing chronic nephritis. In addition, the serovar pomona was isolated from the kidneys of 87.5% of the slaughter pigs examined. The success of these isolations was attributed in part to the refining of 2 existing isolation techniques which complement each other. Using the microscopic agglutination test, serum samples taken from the same farming unit showed evidence of antibodies to the serovar pomona in 89 ou...
A rapid microtitration serum agglutination test for the detection of contagious equine metritis antibodies. A microtitration serum agglutination test, based on that used for brucellosis, has been developed to detect antibodies in the sera of horses exposed to the contagious equine metritis (CEM) organism. Two known positive sera were tested 100 times in 15 separate tests. The results were reproducible to within a twofold range. The test is capable of being carried out within 100 min.
A short, reliable, highly reproducible complement fixation test for the serological diagnosis of contagious equine metritis. A complement fixation test, using round-bottomed microtitration plates and an 8 channel microdiluter, based on that used for brucellosis by Herr, Huchzermeyer, Te Brugge, Williamson, Roos & Schiele, 1985, has been developed for use on the sera of horses to detect antibodies to the contagious equine metritis organism. The results with 2 known positive sera tested 116 times in 27 separate tests were reproducible for the most part within a twofold range. They seldom exceeded these limits and never exceeded a fourfold range. The test itself is capable of being carried out within 90 min. The test w...
Parasites of domestic and wild animals in South Africa. XX. Arthropod parasites of the Cape mountain zebra (Equus zebra zebra). The arthropod parasite burdens of 14 Cape mountain zebra (Equus zebra zebra), shot for survey purposes in the Mountain Zebra National Park in the eastern Cape Province, were determined. Three species of Gasterophilus larvae and 9 ixodid tick species were recovered. Larvae of Gasterophilus pecorum were the most numerous of the fly larvae recovered and Margaropus winthemi was the most abundant tick. Two horses examined in the park were infested with 3 species of Gasterophilus larvae and 7 species of ixodid ticks.
Paralysis and lipofuscin-like pigmentation of farm stock caused by the plant, Trachyandra laxa var. laxa. A paralytic condition of farm stock in South West Africa, characterized by prominent neuronal and some mild extraneuronal pigmentation, is described. The distribution of the pigment, which was mainly located in the larger neurones of the brain and spinal cord, is given. Experimental evidence, obtained by feeding the plant, is presented that the condition is caused by Trachyandra laxa var. laxa. The histochemical features of the pigment proved to be compatible with a lipofuscin.
The use of a single complement fixation test technique in bovine brucellosis, Johne’s disease, dourine, equine piroplasmosis and Q fever serology. The same techniques may be used in the complement fixation test (CFT) for the serological diagnosis of bovine brucellosis, Johne's disease (paratuberculosis), dourine, equine piroplasmosis and Q fever (caused by Coxiella burnetii). The reproducibility of results is excellent, falling for the most part within the twofold range and never exceeding the fourfold range. Agreement with other laboratories is excellent (i.e. within twofold) in the case of brucellosis and equine piroplasmosis antibody titres. A good correlation between the occurrence of the disease and serological reactions is found on...
Arthropod parasites of Hartmann’s mountain zebra, Equus zebra hartmannae, in South West Africa/Namibia. Twelve Hartmann's mountain zebra, Equus zebra hartmannae, were shot for arthropod parasite recovery during the period June 1980-June 1981 on a farm in the Khomas Hochland region of South West Africa/Namibia. Four species of Gasterophilus larvae, 1 species of Rhinoestrus larvae and 3 ixodid tick species were recovered. The seasonal prevalence of the Gasterophilus species larvae and of Rhipicephalus evertsi mimeticus was determined. Three horses examined on the same farm were infested with larvae of 2 Gasterophilus species and with the same ixodid tick species as the zebras.
Studies on the physiopathology of chronic obstructive pulmonary disease in the horse. VIII. Mean modal vectors of the P wave and the QRS complex. Mean modal vectors of P1, P2 and QRS were determined in the 3 planes of a semi-orthogonal EKG lead system in 17 horses and ponies with chronic obstructive pulmonary disease (COPD) and in 17 clinically normal horses and ponies. Subjects were paired so that the heart rates of each pair were not dissimilar by more than 2 cycles per minute. Probably significant differences were observed between the mean angles of P1 vectors in the transverse and sagittal planes (T plane, normal = 324 degrees +/- 24,6 degrees, COPD = 342 degrees +/- 21,0 degrees, t = 2,0, P less than 0,05; S plane, normal = 331 deg...
A survey on neoplasia in domestic species over a 40-year period from 1935 to 1974 in the Republic of South Africa. IV. Tumours occurring in Equidae. A survey was carried out on the neoplasms of horses, donkeys and mules which are recorded in the registration files of the Section of Pathology of the Veterinary Research Institute, Onderstepoort, in the Republic of South Africa, over a 40-year period from 1935 to 1974. A total of 378 tumours are recorded, 339 of which were in horses, 32 in mules and 7 in donkeys. Sarcoids (38%), squamous cell carcinomas (23,5%), fibromas (8,2%), melanomas (8,0%), papillomas (4,5%), fibrosarcomas (3,4%) and lymphosarcomas (3,0%) accounted for 88,6% of the total. Of the 58 sarcoids for which the site or origin ...
A morphological study of the lesions of African horsesickness. Gross, histological and ultrastructural findings are described in 6 natural cases and in 2 experimental cases of African horsesickness. From the gross lesions the cases were divisible into 2 groups which represented the previously described pulmonary and mixed forms of the disease. Histologically, abundance of fibrin and inflammatory cells in oedematous lung suggests that the pulmonary lesion is an exudative pneumonia. Lymphoid depletion and necrosis in germinal centres were consistently present. Electron microscopy failed to demonstrate virus particles or virus-associated structures in the ti...
Studies on the physiopathology of chronic obstructive pulmonary disease in the horse. VII. Percentage venous admixture. The percentage venous admixture was calculated in 21 clinically normal horses and ponies and in 13 horses and ponies with chronic obstructure pulmonary disease (COPD). The oxygen contents of pulmonary end-capillary blood, arterial and mixed venous blood were calculated from blood and respiratory gas values and substituted in the shunt equation. The mean percentage venous admixture of the COPD subjects was significantly greater than that of the normal subjects. It was concluded that a larger proportion of alveoli in the lungs of COPD subjects were hypoventilated than that of alveoli of the norm...
Studies on Strongylus asini. I. Experimental infestation of equines. Infective larvae were harvested from a culture of eggs collected from adult Strongylus asini recovered from a free-ranging Burchell's zebra, Equus burchelli, in the Kruger National Park. Worm-free zebra, horse and donkey foals were successfully infested, but infestation failed in a mule foal. At slaughter, 117-125 days post-infestation, S. asini in their 4th moult were recovered from the liver and portal veins. This is the first report of successful experimental infestation of these hosts with S. asini.
Studies on the physiopathology of chronic obstructive pulmonary disease in the horse. V. Blood gas and acid-base values during exercise. The haemoglobin concentration, the partial pressures of oxygen and carbon dioxide, the oxygen content and the pH were determined in the arterial and mixed venous blood of 5 normal and 3 horses with chronic obstructive pulmonary disease (COPD) at 3 stages of an exercise distance of 1200 m. Arterial and mixed venous samples were collected simultaneously by means of an automatic technique during the walk, trot and gallop at 0-100 m, at 500-600 m and at 1100-1200 m. The standard bicarbonate and the lactic and pyruvic acid concentrations were also determined in arterial and mixed venous blood. High...
Recovery of helminths postmortem from equines. II. Helminths and larvae of gasterophilus in the gastro-intestinal tract and oestrids from the sinuses. The tongue, pharynx, oesophagus and gums are examined for larvae of gasterophilus spp., and the nose and sinuses for oestrid larvae. The gastro-intestinal tract is divided into separate specimens-stomach, small intestine, caecum, ventral colon, dorsal colon, descending colon and rectum- and each is examined separately. Aliquots of ingesta of 1/4 by mass of the stomach and 1/10 by mass of the small intestine, caecum, ventral colon and dorsal colon are collected for microscopic examination. Each part of the wall of the caecum, ventral and dorsal colon is washed and specimens are collected for su...
Recovery of helminths postmortem from equines. I. Parasites in arteries, subperitoneum, liver and lungs. The entire gastro-intestinal tract and viscera of the abdomen and thorax, including the heart, aorta and its branches to the viscera, are removed from the carcass. All the branches of the aorta, with the exception of the A. gastrica sinistra, are dissected from the intestinal tract, and subsequently each branch is isolated from the mesentery, fat, pancreas, kidneys, etc. Usually, the A. ileocolica is grossly enlarged due to chronic arteritis with thrombus formation caused by 4th stage larvae, 4th moult and 5th stage Strongylus vulgaris. Descriptions of methods to examine the subperitoneal tiss...
A comparative study of the toxicity of Fusarium verticillioides (= F. moniliforme) to horses, primates, pigs, sheep and rats. An isolate of Fusarium verticillioides (MRC826) that induced experimental leukoencephalomalacia, also caused acute toxicity when fed to pigs and administered per rumen fistula to sheep. Pigs developed severe pulmonary oedema while sheep manifested severe nephrosis and hepatosis. A less toxic isolate (F. verticillioides MRC602), fed to baboons, resulted in acute congestive heart failure or hepatic cirrhosis, depending on the dose. Both isolates were toxic to rats and caused similar lesions, namely, hepatic cirrhosis and intraventricular cardiac thrombosis.
Studies on the physiopathology of chronic obstructive pulmonary disease in the horse. IV. Blood gas and acid-base values at rest. Radiometer Blood Micro-system 2 was used in studies designed to, (a) compare the mean blood gas and acid-base values of 38 normal horses and 20 horses with chronic obstructive pulmonary disease (COPD), (b) determine the means and standard deviations of blood gas and acid-base values of Thoroughbred horses in training, and (c) investigate the relationships between clinical data, blood gas values, intracardiac and pulmonary arterial pressures in subjects with COPD. There were significant differences between the mean values for partial pressure of arterial oxygen (PaO2), arterial carbon dioxide (...
Studies on the physiopathology of chronic obstructive pulmonary disease in the horse. III. The intrathoracic pressure. The intrathoracic pressure was determined by direct intrapleural cannulation in 17 clinically normal horses and 14 horses with chronic obstructive pulmonary disease (COPD). There were significant differences between the normal and COPD horses with regard to max. Ppl and max. delta Ppl. The mean values for minimum Ppl of the 2 groups of subjects were not significantly different. The results were discussed in relation to those of other workers.
Studies on the physiopathology of chronic obstructive pulmonary disease in the horse. II. Right heart haemodynamics. Pressure curves obtained by cardiac catheterization of the pulmonary artery, right ventricle and right atrium of 9 horses and ponies with chronic obstructive pulmonary disease (COPD) were compared with those similarly recorded from 6 clinically normal control subjects. The mean pulmonary peak systolic, pulmonary minimum diastolic and ventricular peak systolic pressures of the COPD subjects were significantly higher (P less than 0,01) than the corresponding mean pressures of the clinically normal control subjects. The mean pressure calculated from pressure curves obtained from 8 Thoroughbreds i...
Studies on the physiopathology of chronic obstructive pulmonary disease in horses. I. Clinical signs. Twenty cases of chronic cough originating in the lung and associated with loss of performance were clinically examined. The physical signs observed were compared with those observed in a control series of 38 clinically normal horses. Reduced work tolerance, coughing for more than 3 months and abnormal pulmonary sounds (râles) were primary signs of chronic obstructive pulmonary disease (COPD). Forced abdominal expiratory efforts and pumping of the anus were regarded as confirmatory signs. Neither nasal discharge nor increased marginal distance was found to be a reliable sign of COPD. The mean ...