1982 Onderstepoort Journal of Veterinary Research, Volume 49, 1982

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CONTENTS

*Volume 49: Number 1*

Studies on the infectivity of Boophilus decoloratus males and larvae infected with Babesia bigemina	Gray, JS & Potgieter, FT	1

Studies on Haemonchus contortus. VI. Attempts to stimulate immunity to abomasal trichostrongylids in Merino sheep	Reinecke, RK, De Villiers, IL & Bruckner, C	3

Helminth and arthropod parasites of springbok, Antidorcas marsupialis, in the Transvaal and western Cape Province	Horak, IG. Meltzer, DGA & De Vos, V	7

The pathology of Rift Valley fever. II. Lesions occurring in field cases in adult cattle, calves and aborted foetuses	Coetzer, JAW	11

Clinical and pathological studies in adult sheep and goats experimentally infected with Wesselsbron disease virus	Coetzer, JAW & Theodoridis, A	19

The value of the microtitre serum agglutination test as a second screening test in bovine brucellosis	Herr, S, Te Brugge, LA & Guiney, MCM	23

Studies on Parafilaria bovicola Tubangui, 1934. III. Pathological changes in infested calves	Coetzer, JAW & Viljoen, JH	29

Parasites of South African freshwater fish. I. Some nematodes of the catfish [Clarias gariepinus (Burchell, 1822)] from the Hartbeespoort Dam	Boomker, JDF	41

Prozones and delayed reactions in the rose bengal test for bovine brucellosis	Herr, S	53

Leptospira interrogans serovar pomona associated with abortion in cattle : isolation methods and laboratory animal histopathology	Herr, S, Riley, AE, Neser, JA, Roux, D & De Lange, JF	57

Parasites of domestic and wild animals in South Africa. XIV. The seasonal prevalence of Rhipicephalus sanguineus and Ctenocephalides spp. on kennelled dogs in Pretoria North	Horak, IG	63

Research communication:

Studies on Haemonchus contortus. VII. The effect of treatment of Trichostrongylus axei prior to challenge with H. contortus	Reinecke, RK, Bruckner, C & De Villiers, IL	69


*Volume 49: Number 2*

Studies on the physiopathology of chronic obstructive pulmonary disease in the horse. VI. The alveolar dead space	Littlejohn, A & Bowles, F	71

The seasonal incidence of helminth parasites and of Oestrus ovis in Karakul sheep in the Kalahari region of South West Africa/Namibia.	Biggs, HC & Anthonissen, M	73

The reproducibility of results in bovine brucellosis serology and their correlation with the isolation of Brucella abortus	Herr, S, Roux, D & Pieterson, PM	79

Parasites of domestic and wild animals in South Africa. XV. The seasonal prevalence of ectoparasites on impala and cattle in the northern Transvaal	Horak, IG	85

Cooperia acutispiculum n. sp. (Nematoda: Trichostrongylidae) from the kudu, Tragelaphus strepsiceros (Pallas, 1766)	Boomker, JDF	95

The effect of incubation and prefeeding of infected Rhipicephalus simus nymphae and adults on the transmission of Anaplasma marginale	Potgieter, FT & Van Rensburg, L	99

Sequential development of the liver lesions in new-born lambs infected with Rift Valley fever virus. I. Macroscopic and microscopic pathology	Coetzer, JAW & Ishak, KG	103

Sequential development of the liver lesions in new-born lambs infected with Rift Valley fever virus. II. Ultrastructural findings	Coetzer, JAW, Ishak, KG & Calvert, RC	109

Immune response to the simultaneous vaccination of day-old chickens with live and inactivated oil-based Newcastle disease vaccines	Pollard, B	123

Seasonal incidence of helminths in the Burchell's zebra	Scialdo, RC, Reinecke, RK & De Vos, V	127

The presence of Paneth cells confirmed in the pig	Myer, MS	131


*Volume 49: Number 3*

Virulence and heterologous strain immunity of South African and Australian Babesia bovis strains with reduced pathogenicity	De Vos, AJ, Bessenger, R & Fourie, CG	133

Tetraphyllin B and epi-tetraphyllin B from Adenia glauca Schinz	Spencer, KC & Seigler, DS	137

Helminth and arthropod parasites of blesbok, Damaliscus dorcas phillipsi, and of bontebok, Damaliscus dorcas dorcas	Horak, IG, Brown, MR, Boomker, JDF, De Vos, V & Van Zyl, EA	139

Helminth and arthropod parasites of vaal ribbok, Pelea capreolus, in the western Cape Province	Horak, IG, De Vos, V & De Klerk, BD	147

Studies on Haemonchus contortus. VIII. Attempts to protect suckling lambs against infestation with H. contortus	Reinecke, RK, De Villiers, IL & Joubert, G	149

Studies on Strongylus asini. I. Experimental infestation of equines	Malan, FS, De Vos, V, Reinecke, RK & Pletcher, JM	151

Babesia bigemina vaccine : comparison of the efficacy and safety of Australian and South African strains under experimental conditions in South Africa	De Vos, AJ, Combrink, MP & Bessenger, R	155

The effect of predosing calves with Trichostrongylus axei on subsequent challenge with Haemonchus placei	Reinecke, RK, De Villiers, IL & Joubert, G	159

Babesia, Theileria and Anaplasma spp. infecting sable antelope, Hippotragus niger (Harris, 1838), in southern Africa	Thomas, SE, Wilson, DE & Mason, TE	163

A study of the pathology of lumpy skin disease in cattle	Prozesky, L & Barnard, BJH	167

Antibody response of guinea-pigs and cattle to a Campylobacter fetus oil emulsion vaccine	Cameron, CM	177


*Volume 49: Number 4*

The ecology of Rhipicephalus zambeziensis and Rhipicephalus appendiculatus (Acarina, Ixodidae) with particular reference to Zimbabwe	Norval, RAI, Walker, JB & Colborne, J	181

Non-bite transmission of rabies in kudu (Tragelaphus strepsiceros)	Barnard, BJH, Hassel, RH, Geyer, HJ & De Koker, WC	191

A simple technique for the rapid diagnosis of rabies in formalin-preserved brain	Barnard, BJH & Voges, SF	193

A survey on neoplasia in domestic species over a 40-year period from 1935 to 1974 in the Republic of South Africa. I. Tumours occurring in cattle	Bastianello, SS	195

A survey on neoplasia in domestic species over a 40-year period from 1935 to 1974 in the Republic of South Africa. II. Tumours occurring in sheep	Bastianello, SS	205

Studies on the physiopathology of chronic obstructive pulmonary disease in the horse. VII. Percentage venous admixture	Littlejohn, A, Bowles, F & Maluleka, W	211

A study on the function of some subcellular systems of the sheep myocardium during gousiekte. I. The energy production system	Snyman, LD, Van der Walt, JJ & Pretorius, PJ	215

A study on the function of some subcellular systems of the sheep myocardium during gousiekte. II. The contractile protein system	Snyman, LD, Van der Walt, JJ & Pretorius, PJ	221

The effect of temperature on the in vitro transcriptase reaction of bluetongue virus, epizootic haemorrhagic disease virus and African horsesickness virus	Huismans, H & Van Dijk, AA	227

Schistosoma mattheei Veglia & LeRoux, 1929, egg output from cattle in a highly endemic area in the eastern Transvaal	Pitchford, RJ & Visser, PS	233

Observations on the clinical, cardiac and histopathological effects of fluoroacetate in sheep	Coetzer, JAW, Schultz, RA, Kellerman, TS & Naude, TW	237

Studies on South African cardiac glycosides. II. Observations on the clinical and haemodynamic effects of cotyledoside	Naude, TW & Schultz, RA	247

Rearing the blood-feeding fly Haematobia thirouxi potans in the laboratory	Doube, BM, Fay, HAC & Aschenborn, HH	255

Slight resistance to the residual effect of closantel in a field strain of Haemonchus contortus which showed an increased resistance after one selection in the laboratory	Van Wyk, JA, Gerber, HM & Alves, RMR	257

Author index		263

Subject index		267

Browse

Now showing 1 - 20 of 50

Subject index
(Published by The Government Printer, Pretoria, 1982) Anonymous; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.
Author index
(Pretoria : Government Printer, 1982) Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.
A simple technique for the rapid diagnosis of rabies in formalin-preserved brain
(Published by The Government Printer, Pretoria, 1982) Barnard, B.J.H.; Voges, S.F.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.
A simple technique is described for the rapid diagnosis of rabies in formalin-preserved brain. Brain tissue was emulsified, washed with phosphate-buffered saline and digested with trypsin. The digested material was stained according to conventional immunofluorescent procedures. Digestion with trypsin markedly enhanced the staining of rabies inclusions and eliminated non-specific staining of formalin-preserved brain. The method seems to be more accurate than histological examination.
Non-bite transmission of rabies in kudu (Tragelaphus strepsiceros)
(Published by The Government Printer, Pretoria, 1982) Barnard, B.J.H.; Hassel, R.H.; Geyer, H.J.; De Koker, W.C.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.
The titres of rabies virus in the saliva of kudu are higher than those of the salivary glands. The high titres are an indication of active excretion and multiplication in tissues other than the salivary glands. Two out of 4 kudu died of rabies after experimental infection by the instillation of infected saliva onto their buccal and nasal mucosae. Mice and 2 cattle resisted a similar exposure. Kudu also developed antibodies against rabies after instillation of HEP Flury virus onto their nasal and buccal mucosae. Cattle did not react when they were treated in the same way. These results suggest a high susceptibility of kudu to rabies when the virus is applied to their mucous membranes.
The ecology of Rhipicephalus zambeziensis and Rhipicephalus appendiculatus (Acarina, Ixodidae) with particular reference to Zimbabwe
(Published by The Government Printer, Pretoria, 1982) Norval, R.A.I.; Walker, Jane B.; Colborne, J.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.
R. zambeziensis, like R. appendiculatus, is primarily a parasite of domestic and wild herbivores, and sometimes carnivores. Both species occur in parts of east, central and southern Africa, but they are not as a rule sympatric. In general, R. zambeziensis occurs in hotter, drier areas than does R. appendiculatus, especially along some of the great river valleys. In Zimbabwe, R. zambeziensis is largely restricted to the northern, northwestern and southern parts of the country, whereas R. appendiculatus is widely distributed in the eastern and southern areas.
Slight resistance to the residual effect of closantel in a field strain of Haemonchus contortus which showed an increased resistance after one selection in the laboratory
(Published by The Government Printer, Pretoria, 1982) Van Wyk, Jan Aucamp; Gerber, H.M.; Alves, Regina M.R.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.
On the strength of a complaint of suspected resistance to closantel, a field strain of Haemonchus contortus was isolated from sheep on a farm near Pretoria and tested for resistance to the remedy, both without exposure to closantel in the laboratory (designated the "unselected" substrain of the parasite) and after a single selection with closantel (called the "selected" substrain). For comparative purpose a few sheep were treated with rafoxanide to ascertain whether the efficacy of this drug was unchanged. While the unselected substrain appeared to show only slight increased resistance to the residual effect of closantel drenched at a dosage rate of 5 mg/kg, there was a dramatic increase in resistance after one selection. The, residual efficacy (determined by the modified NPM test of Groeneveld & Reinecke, 1969, as outlined by Reinecke, 1973), 13-14 days after treatment with closantel was reduced from the registered claim of the remedy in South Africa of >80% effective in >80% of the treated flock to "ineffective", or <50% effective in < 50% of the treated flock. Furthermore, there also appeared to be a slight increase in the resistance of this substrain to rafoxanide, as its efficacy was reduced from 99-100% to about 92%. This sharp reduction in efficacy after a single selection with closantel seemed to indicate that the slight increase in resistance of the unselected substrain was probably due not to possible variation in the repeatability of the trail method but to repeated treatment with closantel on the farm.
Rearing the blood-feeding fly Haematobia thirouxi potans in the laboratory
(Published by The Government Printer, Pretoria, 1982) Doube, B.M.; Fay, H.A.C.; Aschenborn, H.H.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.
Two methods for rearing the African blood-feeding fly Haematobia thirouxi potans in the laboratory are described. The adult flies can be fed either on a bovine calf or in vitro, where they produced viable eggs only when provided with a 2% sodium/potassium chloride solution in addition to citrated bovine blood. The larvae were fed bovine dung.
Studies on South African cardiac glycosides. II. Observations on the clinical and haemodynamic effects of cotyledoside
(Published by The Government Printer, Pretoria, 1982) Naude, T.W.; Schultz, R.A. (Rowena Anitra); Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.
Cotyledoside, a bufadienolide isolated from Tylecodon wallichii (Harv.) Toelken, subs. wallichii (=Cotyledon wallichii Harv.), was dosed to guinea-pigs and sheep. In guinea-pigs, the oral and subcutaneous LD₅₀ values were very similar (cf. 0,173 mg/kg over 48 h with 0,116 mg/kg over 24 and 48 h). When dosed subcutaneously, a cumulative effect was observed. Intravenous administration of cotyledoside to anaesthetized guinea-pigs resulted in: dyspnoea, increased heart rates and blood pressures, and electrocardiagraphic changes typical of cardiac glycoside poisoning. A positive cardiac inotropic effect was succeeded by a positive chronotropic one. In sheep, acute and subacute intoxication resulted in ruminal, respiratory and cardiac changes. The signs included ruminal stasis, cyanosis, cardiac arrhythmia, ectopic foci and AV dissociation, followed by hypotension and progressive respiratory and cardiac failure. The skeletal muscles were affected in only 1 sheep vide infra. In chronically intoxicated sheep typical clinical signs of "krimpsiekte" developed, e.g. weakness, reluctance to stand, unsteadiness on feet, tremor and paresis of hindquarter muscles, paresis of the neck, arching of the back and standing with the feet close together. Respiratory function was affected in all 3 cases; ruminal stasis, with concomitant loss of appetite occurring in one, and a transient change in heart function in another. The syndrome induced by acute cotyledoside poisoning is similar to that of other cardiac glycosides, but the paretic signs of chronic intoxication resemble "krimpsiekte", a disease associated only with intoxication with the plants of the family Crassulaceae.
Observations on the clinical, cardiac and histopathological effects of fluoroacetate in sheep
(Published by The Government Printer, Pretoria, 1982) Schultz, R.A. (Rowena Anitra); Kellerman, T. Stephanus; Naude, T.W.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.; Coetzer, Jacobus A.W.
Fluoroacetate was dosed per stomach tube to 17 Merino sheep at the rate of 0,05 - 1,0 mg/kg/day. The clinical signs, haemodynamic changes, chemical pathology and pathology of acute, subacute and chronically intoxicated cases are described. Tetanic convulsions were seen in acutely intoxicated animals and in them respiratory failure, occurring concomitantly with cardiac failure, may have been the cause of death. Subacute intoxication resulted in less conspicuous clinical signs when the sheep were at rest, but they developed apparent nervous signs on being handled, and later tended to lie down. Chronically intoxicated animals were only mildly affected. At all levels of intoxication changes in the chemical pathological parameters were either absent or were mild and transient. The microscopic lesions in the hearts of acutely intoxicated sheep included degeneration as well as necrosis of individual or small groups of myocardial fibres. In the subacutely and chronically intoxicated animals the multifocal myocardial lesions were more widespread and in various stages of development or resolution.
Schistosoma mattheei Veglia & LeRoux, 1929, egg output from cattle in a highly endemic area in the eastern Transvaal
(Published by The Government Printer, Pretoria, 1982) Pitchford, R.J.; Visser, P.S.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.
The results of 6-month estimations of S. mattheei faecal egg counts on 513 cattle in a highly endemic area of the eastern Transvaal over a 2-year period are given. After an initial high egg output of short duration the egg counts stabilized at a low level. The frequency of high egg counts in young cattle which died naturally was more than twice that of all other cattle, suggesting that S. mattheei egg counts in highly endemic areas is debatable, and it is suggested that egg counts in man might follow a similar pattern.
A study on the function of some subcellular systems of the sheep myocardium during gousiekte. I. The energy production system
(Published by The Government Printer, Pretoria, 1982) Snyman, L.D.; Van der Walt, J.J.; Pretorius, P.J.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.
In order to determine the status of the energy production system of the heart during cardiac failure of sheep with gousiekte, observations were made of the heart tissue levels of adenosine triphosphate (ATP), creatine phosphate (CrP), inorganic phosphate, reduced nicotine adenine dinucleotide (NADH) and lactate. Some measurements on oxidative phosphorylation were also made. A significant decrease in ATP and CrP levels coincided with a simultaneous rise in the ATP:CrP ratio and lactate levels in gousiekte hearts. No significant deviations in inorganic phosphate and NADH levels could be demonstrated. These abnormalities were accompanied by a decreased uptake of oxygen by isolated mitochondria of gousiekte hearts. There was a marked increase in the anaerobic state of the hearts of dying gousiekte sheep, while the values of NADH and the ATP:CrP ratio at a presymptomatic stage indicated a possible early derangement in the energy metabolism of sheep fed the toxic material. No hypertrophy could be detected for the failing ventricles of gousiekte sheep after being corrected for a significant amount of oedema found in the heart tissue of these animals. It was concluded that the depressed ATP and CrP levels in the heart tissue of gousiekte sheep during cardiac failure could at least in part, be attributed to a depressed aerobic energy production. It is not possible, however, to state whether this is a primary or a secondary response due to intoxication and also whether it could be seen as a cause or effect of cardiac failure.
Studies on the physiopathology of chronic obstructive pulmonary disease in the horse. VII. Percentage venous admixture
(Published by The Government Printer, Pretoria, 1982) Littlejohn, A.; Bowles, Felicity; Maluleka, W.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.
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 normal lungs.
A survey on neoplasia in domestic species over a 40-year period from 1935 to 1974 in the Republic of South Africa. II. Tumours occurring in sheep
(Published by The Government Printer, Pretoria, 1982) Bastianello, Stella S.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.
A survey was carried out on all ovine neoplasms recorded in the registration files of the Section of Pathology of the Veterinary Research Institute at Onderstepoort over a 40-year period from 1935 to 1974. The neoplasms were divided and tabulated into 8 groups according to body systems or tissue types. Out of a total of 673 neoplasms, 436 (64,8%) were cases of jaagsiekte (pulmonary adenomatosis). Of the remaining 237 neoplasms, 41,3% involved the skin. Eighty per cent of the cutaneous neoplasms were squamous cell carcinomas which varied from well-differentiated to anaplastic. The majority occurred on the head, in particular on the ears, frontal region and on the eyelids or nictitating membrane. Several factors have been suggested to explain the high incidence of squamous cell carcinomas on the head. Lymphosarcomas were the 3rd most commonly encountered tumours, whilst a significant number of hepatocellular carcinomas also occurred. A variety of tumours of connective tissue origin were recorded, the most common of which arose from fibrous tissue and cartilage.
A survey on neoplasia in domestic species over a 40-year period from 1935 to 1974 in the Republic of South Africa. I. Tumours occurring in cattle
(Published by The Government Printer, Pretoria, 1982) Bastianello, Stella S.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.
A survey was carried out on all the bovine neoplasms recorded in the registration files of the Section of Pathology of the Veterinary Research Institute, Onderstepoort, Republic of South Africa, over a 40-year period from 1935 to 1974. The 606 neoplasms were divided and tabulated into 20 groups according to body systems or tissue types. Skin, connective tissue, lymphoid tissue and ocular tumours in that order accounted for the majority of neoplasms. Squamous cell carcinoma was the most frequent neoplasm and the 2 main sites for it were the eye and the vulva. Fibromas and fibrosarcomas made up the majority of the connective tissue tumours. The lymphoid tissue tumours, composed almost entirely of lymphosarcomas, were the 3rd most common group of tumours. Penile fibropapillomas and cutaneous papillomas were commonly encountered, and there was also a noteworthy incidence of melanomas, mesotheliomas and neurofibromas. The male and female genital tracts were relatively frequently neoplastic, due principally to the occurrence of penile fibropapillomas, vulvar squamous cell carcinomas and uterine carcinomas. The incidence of respiratory, hepatic and vascular system tumours was moderate, whilst tumours of the endocrine, central nervous, skeletal and muscular systems were rarely encountered.
The effect of temperature on the in vitro transcriptase reaction of bluetongue virus, epizootic haemorrhagic disease virus and African horsesickness virus
(Published by The Government Printer, Pretoria, 1982) Van Dijk, A.A.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.; Huismans, H. (Henk), 1942-
Virions of bluetongue virus (BTV), epizootic haemorrhagic disease virus (EHDV) and African horsesickness virus (AHSV) can be converted to core particles by treatment with chymotrypsin and magnesium. The conversion is characterized by the removal of the 2 outer capsid polypeptides of the virion. The loss of these 2 proteins results in an increase in density from 1,36g/ml to 1,40g/ml on CsC1 gradients. The BTV, EHDV and AHSV core particles have an associated double-stranded RNA dependent RNA transcriptase that appears to transcribe mRNA optimally at 28⁰C. It was found, at least in the case of BTV, that this low temperature preference is not an intrinsic characteristic of the transcriptase, but is due to a temperature-dependent inhibition of transcription at high core concentrations.
A study on the function of some subcellular systems of the sheep myocardium during gousiekte. II. The contractile protein system
(Published by The Government Printer, Pretoria, 1982) Snyman, L.D.; Van der Walt, J.J.; Pretorius, P.J.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.
Two groups of Merino sheep were intoxicated separately and at different times with "gousiektebossie" (Pachystigma pygmaeum) until definite symptoms of heart failure were auscultated. Cardiectomy was carried out and some ventricular muscle from I group was stored in 50% glycerol at -20⁰C for about 4 months. Natural actomyosin (n-actomyosin) was subsequently extracted and tested for magnesium, calcium and adenosine triphosphate (ATP)-dependent adenosine triphosphatase (ATP-ase) activity as well as for superprecipitation characteristics. Muscle strips were taken from the other group and stored for 2 weeks in 50% glycerol at -20⁰C, where after it was analysed for an isometric tension-calcium response. The data showed no difference between gousiekte and control sheep in the sensitivity of the contractile system to the activating effect of calcium ions with respect to isometric tension development. A significant reduction of the magnesium dependent ATP-ase was found for gousiekte n-actomyosin in either the presence or absence of calcium ions. A depressed sensitivity for this enzyme to increasing concentrations of ATP in comparison to controls was also found ([ATP] < 1mM, [MgC1₂] = 1mM). No significant difference could be detected in the sensitivity of the n-actomyosin:ATP-ase system to magnesium. n-Actomyosin:ATP-ase of gousiekte hearts revealed a depressed sensitivity to calcium ions. Gousiekte n-actomyosin also showed a significant depression in the rate of superprecipitation with a concomitant increase in the duration of the clearing phase. We conclude from these observations that a definite biochemical lesion is induced in the contractile proteins of heart muscle obtained from sheep intoxicated with "gousiektebossie" at the stage of cardiac failure. This condition is characterized by abnormal superprecipitation characteristics and a depressed n-actomyosin:ATP-ase activity, showing a reduced sensitivity to the activating effect of calcium ions.
Antibody response of guinea-pigs and cattle to a Campylobacter fetus oil emulsion vaccine
(Published by The Government Printer, Pretoria, 1982) Cameron, Colin McKenzie; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.
A method is described for the mass production of Campylobacter fetus oil emulsion vaccine, using 2 strains of C. fetus ss intestinalis and a strain of C. fetus ss intermedius as a substitute for C. fetus ss venerialis. Heifers, given 2 injections of the vaccine, developed serum antibody titres comparable with the response induced by a commercial product.
A study of the pathology of lumpy skin disease in cattle
(Published by The Government Printer, Pretoria, 1982) Barnard, B.J.H.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.; Prozesky, Leon
Microscopic lesions in cattle infected with the virus of the Neethling form of lumpy skin disease comprised a granulomatous reaction in the dermis and hypodermis which extended to the surrounding tissue. During the early stages of the lesions a vasculitis and lymphangitis with concomitant thrombosis and infarction resulted in necrosis and oedema. A hallmark of the acute to subacute stages of the lesions was the presence of intracytoplasmic eosinophilic inclusions in various cell types. The inclusions consisted of the viroplasm which was identified as aggregates of electron-dense, finely granular to fibrillar deposits in which membrane-enclosed virions and occasional groups of tubular structures were observed. Various cytopathogenic changes were observed in cells exhibiting viral proliferation. The morphogenesis of the virions is discussed in relation to the cytopathogenic changes.
The effect of predosing calves with Trichostrongylus axei on subsequent challenge with Haemonchus placei
(Published by The Government Printer, Pretoria, 1982) Joubert, Gerda; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.; Reinecke, R.K.; De Villiers, I.L.
Twelve calves were dosed with 40 000 and a further 12 with 80 000 infective larvae of Trichostrongylus axei respectively. These 2 groups and a control group were subsequently dosed with 50 000 infective larvae of Haemonchus placei. Predosing with T. axei had no effect on the establishment of H. placei. It is postulated that the numbers of T. axei worms present were below the 'threshold' value necessary to protect the calves against challenge with H. placei.
Studies on Haemonchus contortus. VIII. Attempts to protect suckling lambs against infestation with H. contortus
(Published by The Government Printer, Pretoria, 1982) Reinecke, R.K.; De Villiers, I.L.; Joubert, Gerda; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; Steyn, P.J.J.
A group of 12 Merino lambs, 3,5 months of age, which were still suckling, were each dosed with 40 000 infective larvae of Trichostrongylus axei on Day 0. From Day +62 - Day 64 each of these lambs and those of a 2nd group of 11 controls were dosed with 30 000 infective larvae of Haemonchus contortus, and all the lambs of both groups were killed on Day +90. Attempts to use T. axei to protect them against subsequent challenge with H. contortus were unsuccessful.

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