1976 Onderstepoort Journal of Veterinary Research, Volume 43, 1976

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CONTENTS

*Volume 43: Number 1*

The fine structure of merozoites of Babesia bovis in the gut epithelium of Boophilus microplus	Potgieter, FT, Els, HJ & Van Vuuren, AS	1

Volatile fatty acid metabolism in sheep. 1. Average daily volatile fatty acid production in the rumen of sheep fed lucerne hay	Van der Walt, JG & Briel, BJ	11

The effect of gamma radiation on the cysticerci of Taenia solium	Verster, A, Du Plessis, TA & Van den Heever, LW	23

Research note:

Ticks from the African buffalo (Syncerus caffer) in Ngamiland, Botswana	Carmichael, IH	27


*Volume 43: Number 2*

Immunization of mice and calves against Salmonella dublin with attenuated live and inactivated vaccines	Cameron, CM & Fuls, WJP	31

The isolation of Mycoplasma synoviae from chickens with infectious synovitis and air-sacculitis in the Republic of South Africa	Buys, SB	39

Studies on schistosomiasis. 8. The influence of age on the susceptibility of sheep to infestation with Schistosoma mattheei	Van Wyk, JA, Van Rensburg, LJ & Heitmann, LP	43

Observations on the transmission, immunology, clinical signs and chemotherapy of dourine (Trypanosoma equiperdum infection) in horses, with special reference to cerebro-spinal fluid	Barrowman, PR	55

Maldronksiekte in cattle : a neuronopathy caused by Solanum kwebense N.E. Br.	Pienaar, JG, Kellerman, TS, Basson, PA, Jenkins, WL & Vahrmeijer, J	67

Research note:

Cerebral babesiosis in a new-born calf	De Vos, AJ, Imes, GD & Cullen, JSC	75


*Volume 43: Number 3*

Gonad development and gametogenesis in Boophilus decoloratus (Koch, 1844) (Acarina: Metastriata: Ixodidae)	Londt, JGH & Spicket, AM	79

Antibody response to and immunity induced by Corynebacterium pyogenes vaccine	Cameron, CM, Botha, WF & Smit, BHJ	97

Ixodes (Afrixodes) Bakeri Arthur & Clifford, 1961 (Acarina: Ixodidae): description of the male and immature stages from rodents and insectivores and notes on its biology in South Africa	Clifford, CM, Walker, JB & Keirans, JE	105

Leukoencephalomalacia: a mycotoxicosis of Equidae caused by Fusarium moniliforme Sheldon	Marasas, WFO, Kellerman, TS, Naude, TW & Pienaar, JG	113

Light and electron microscopic observations on the development of small merozoites of Babesia bovis in Boophilus microplus larvae	Potgieter, FT & Els, HJ	123

Q fever in cattle and sheep in Southern Africa. A preliminary report	Schutte, AP, Kurz, J, Barnard, BJH & Roux, DJ	129

Transmission of jaagsiekte (ovine pulmonary adenomatosis) by means of a permanent epithelial cell line established from affected lungs	Coetzee, S, Els, HJ & Verwoerd, DW	133

Fertilization capacity of Boophilus decoloratus (Koch, 1844) (Acarina: Ixodidae)	Londt, JGH	143

A highly fatal tremorgenic mycotoxicosis of cattle caused by Aspergillus clavatus	Kellerman, TS, Pienaar, JG, Van der Westhuizen, GCA, Anderson, LAP & Naude, TW	147

Research note:

Bluetongue virus as a cause of hydranencephaly in cattle	Barnard, BJH & Pienaar, JG	155


*Volume 43: Number 4*

A study on the pathogenesis of bluetongue : replication of the virus in the organs of infected sheep	Pini, A	159

The antibody response of cattle to Clostridium botulinum types C and D toxoids	Jansen, BC, Knoetze, PC & Visser, F	165

Relation between macrophage migration inhibition and immunity to Brucella abortus in guinea-pigs	Cameron, CM, Van Rensburg, JJ & Engelbrecht, MM	175

Kinetics of the IgM and IgG immunological response to sheep erythrocytes and bluetongue virus in mice	Oellermann, RA, Carter, P & Marx, MJ	185

The isolation and preliminary genetic classification of temperature-sensitive mutants of bluetongue virus	Shipham, SO & De la Rey, M	189

A gel electrophoretic study of the protein and nucleic acid components of African horsesickness virus	Bremer, CW	193

Research note:

Experimental intraspinal Trypanosoma equiperdum infection in a horse	Barrowman, PR	201

Author index		203

Subject index		205

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Now showing 1 - 20 of 29

Author index
(Pretoria : Government Printer, 1976) Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
Subject index
(Pretoria : The Government Printer, 1976) Anonymous; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
The fine structure of merozoites of Babesia bovis in the gut epithelium of Boophilus microplus
(Pretoria : The Government Printer, 1976) Potgieter, F.T.; Els, H.J.; Van Vuuren, A.S.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
Electron microscopic studies on merozoites of Babesia bovis in epithelial cells of the gut of Boophilus microplus revealed that the pellicle apparently consists of 3 membranes, and an osmiophilic layer intimately associated with microtubules. Micropores in the pellicle were often associated with micronemes. An unidentified tubular structure extended from the anterior polar ring to the nuclear region where it appeared to be associated with the nuclear envelope. A Golgi complex, typical protozoan mitochondria, food vacuoles and rhoptries could not be identified.
A highly fatal tremorgenic mycotoxicosis of cattle caused by Aspergillus clavatus
(Published by The Government Printer, Pretoria, 1976) Pienaar, J. G.; Van der Westhuizen, G.C.A.; Anderson, L.A.P.; Naude, T.W.; Kellerman, T. Stephanus; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
During February 1975, a tremorgenic neurotoxicosis decimated a herd of cattle in the northern Transvaal. This hitherto unidentified disease was characterized by hypersensitivity, incoordination, a peculiar stiff-legged gait of the hind legs, severe generalized tremors of the skeletal muscles, progressive paresis, paralysis and constipation. The most notable gross pathological lesions were degenerative and necrotic changes in certain skeletal muscles, haemorrhages on the serosal surfaces, especially on the dorsal aspect of the rumen, and gastro-intestinal stasis. Microscopical examination of the central nervous system revealed cytopathological changes consisting of degeneration and necrosis of the large motor cells in the ventral horns of the spinal cord and bigger neurones in numerous nuclei of the medulla oblongata, midbrain and thalamus. By feeding the suspect ration and its component parts to cattle and sheep, it was possible to identify mouldy sorghum beer residue as the toxic component in the ration. A. clavatus. the dominant fungus on the toxic residue, was readily isolated in pure culture. The entire syndrome was then reproduced in a yearling Friesland steer dosed with pure cultures of the A. clavatus isolate grown on autoclaved non-toxic sorghum beer residue. The toxic principle is not known, but it does not appear to be patulin, tryptoquivalone, tryptoquivaline, or any other known tremorgen.
Fertilization capacity of Boophilus decoloratus (Koch, 1844) (Acarina : Ixodidae)
(Published by The Government Printer, Pretoria, 1976) Londt, J.G.H.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
Thirty individual Boophilus decoloratus (Koch, 1844) males were studied daily, some during the whole observation period of 37 days. Newly moulted males spent a mean of 3, 8 days (range 3- 6) on the host before mating. Males mated w1th between 1- 8 females (mean 4, 6), spending 2,6 days (range 1- 10) with each and 0,5 days (range 0-4) in between females. The time spent by adult males on the host was from 9-37 days. The ability for males to produce viable offspring remained fairly constant with each successive female fertilized. Development took place in eggs produced by unfertilized female ticks but only a very small percentage (mean 0, 008 %) of these eggs hatched.
Transmission of jaagsiekte (ovine pulmonary adenomatosis) by means of a permanent epithelial cell line established from affected lungs
(Published by The Government Printer, Pretoria, 1976) Coetzee, S.; Els, H.J.; Verwoerd, Daniel Wynand; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
An epithelial cell line, designated JS-15. 4, has been established in culture from jaagsiekte lesions and subcultured in vitro for almost 2 years. It exhibits morphological and other features of transformed cells and has been shown by electron microscopy to consist of type B ovine alveolar epithelial cells. Jaagsiekte was successfully transmitted to 3 new-born lambs by the intratracheal injection of cells following immunosuppressive treatment with either anti-thymocyte immunoglobulin alone or combined with anti-macrophage immunoglobulin. Incubation periods as short as 10 weeks were recorded. Evidence was also obtained that natural transmission may result from the inhalation of viable cells.
Kinetics of the IgM and IgG immunological response to sheep erythrocytes and bluetongue virus in mice
(Published by The Government Printer, Pretoria, 1976) Oellermann, R.A.; Carter, P.; Marx, M.J.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
The IgM and IgG response of mice to sheep erythrocytes (SRBC) and bluetongue virus (BTV) was determined by means of haemolytic plaque assays. Maximum primary IgM response to SRBC occurred after 4 days but declined rapidly to 4% of the maximum by Day 9. A lag period of about 2 days was observed in the appearance of IgG haemolytic plaque-forming cells (PFC) but they reached a maximum after 6-9 days. Secondary immunization resulted in the stimulation particularly of IgG PFC and from Day 6 onwards IgG predominated in the immunological response. The IgM response to BTV was remarkably similar to that observed when SRBC were used as antigen. IgG PFC, however, appeared within a day of the IgM, reaching a peak on Days 4-5. From then onwards, IgG PFC predominated in the response. At BTV concentrations of up to 10 µg per mouse, the virulent strain of BTV type 3 produced the weakest response. At higher antigen concentrations there was very little difference in the response to the serotypes tested, although the virulent strain of BTV type 4 tended to produce the strongest response.
Relation between macrophage migration inhibition and immunity to Brucella abortus in guinea-pigs
(Published by The Government Printer, Pretoria, 1976) Cameron, Colin McKenzie; Van Rensburg, J.J.; Engelbrecht, Maria M.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
A soluble protein antigen was prepared from Brucella melitensis Rev I with which macrophage migration inhibition (MMI) assays were successfully done using guinea-pig peritoneal exudate cells. By comparing the MMI, agglutinin response and immunity of groups and of individual guinea-pigs which had been immunized with either B. melitensis Rev I live vaccine or B. melitensis Rev I inactivated antigen, an association between the MMI and resistance to infection was demonstrated.
Q fever in cattle and sheep in Southern Africa. A preliminary report
(Published by The Government Printer, Pretoria, 1976) Schutte, A.P.; Kurz, J.; Barnard, B.J.H.; Roux, D.J.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
In the course of a study initiated to elucidate the role of known abortifacient agents in ruminants in Southern Afnca, Coxiella burnetii was identified in smears prepared from bovine and ovine placental tissues obtained from 12 farms . The organism was also isolated in embryonated eggs, and specific antibodies were demonstrated in sera of animals originating from these farms. In 7 of the 12 herds in which Q fever was diagnosed, other pathogens were identified concomitantly.
The antibody response of cattle to Clostridium botulinum types C and D toxoids
(Pretoria : The Government Printer, 1976) Jansen, B.C.; Knoetze, P.C.; Visser, Fleur; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
The resistance of cattle with varying serum-antitoxin titres was determined by per os challenge. The results proved that a solid immunity can be produced against C. botulinum toxins C₁ and D. The immune response of cattle to various quantities of C. botulinum C₁ and D toxoids, aluminum phosphate adsorbed and in water-in-oil emulsion was investigated. The response to antigen in watering oil emulsion was far superior to the other when they were used for primary and secondary stimuli. When cattle had been given a solid basic immunity with 2 injections of antigen in water-in-oil emulsion, essentially the same booster effect was obtained with antigen in water-in-oil emulsion and in aqueous solution. Only some of the animals injected intramuscularly with antigens in water-in-oil emulsion developed local lesions. These lesions were not large and their histological picture indicated a noticeable decline in severity within 20 weeks. A case is thus made out for the use of C. botulinum C₁ and D toxoids in water-in-oil emulsion for the primary and secondary stimuli and an aqueous solution of these antigens for any booster stimulus as an improved method of protecting cattle against botulism.
A study on the pathogenesis of bluetongue : replication of the virus in the organs of infected sheep
(Published by The Government Printer, Pretoria, 1976) Pini, A.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
The pathogenesis of bluetongue infection was studied by the titration of the virus in tissue samples taken from sheep inoculated subcutaneously in the auricula of the ear with 76 TC ID₅₀ the plaque-purified type 10 bluetongue virus. Tissue samples were taken from individual animals killed at daily intervals over a period of 11 days. The mean incubation time was 6, 9 days and the first clinical sign was pyrexia. On the 4th day, bluetongue virus was demonstrated in the lymph nodes of the cephalic area, tonsils and spleen; viraemia became demonstrable on the 6th day post-inoculation and typical macroscopic lesions due to the virus were first observed on the 8th day. It was concluded that, post-infection, the virus entered the regional lymph nodes. From there it was disseminated via the lymph and/or the blood stream to the lymphoid tissues in other parts of the body where further replication occurred. From these primary sites the virus was carried via the blood stream and infected the majority of tissues. Humoral antibody, as detected by immunofluorescence, did not appear to have a direct influence on the concentration of virus in solid tissues. Persistence of the virus in infected sheep was not demonstrated when tissues were taken 6, 8 and 16 weeks after infection.
Light and election microscopic observation on the development of small merozoites of Babesia bovis in Boophilus microplus larvae
(Published by The Government Printer, Pretoria, 1976) Els, H.J.; Potgieter, F.T.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
The development of small pyriform merozoites of B. bovis in the granule-secreting cells of the salivary glands of B. microplus larvae, studied with a light microscope, showed a close resemblance to that of B. argentina described by Riek (1966) in the same tick vector. Development took place through a process of schizogony and resulted in the formation of many merozoites. A study of the ultrastructure of developing merozoites in the schizont revealed the following: a poorly defined outer membrane; a granular osmiophilic inner membrane; anterior and posterior polar rings; rhoptries; micronemes; microtubules; a nucleus; spherical bodies of varying size. The schizonts were membrane-bound but no parasitophorous vacuoles were seen.
Bluetongue virus as a cause of hydranencephaly in cattle
(Published by The Government Printer, Pretoria, 1976) Barnard, B.J.H.; Pienaar, J.G.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
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.
Maldronksiekte in cattle : a neuronopathy caused by Solanum kwebense N.E. Br.
(Published by The Government Printer, Pretoria, 1976) Pienaar, J.G.; Kellerman, T.S.; Basson, P.A.; Jenkins, W.L.; Vahrmeijer, J.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
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.
Leukoencephalomacia : A mycotoxicosis of equidae caused by Fusarium moniliforme Sheldon
(Published by The Government Printer, Pretoria, 1976) Marasas, Walter F.O. (Walter Friedrich Otto); Naude, T.W.; Pienaar, J.G.; Kellerman, T. Stephanus; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
When 2 horses were dosed with cultures of a Fusarium moniliforme isolate that had previously caused only hepatosis, 1 developed brain oedema and hepatosis, and the other only leukoencephalomalacia. A 3rd horse developed both leukoencephalomalacia and hepatosis after being dosed with another isolate obtained from maize which was associated with a natural outbreak of the nervous form of the disease. Since leukoencephalomalacia and hepatosis could be induced by the same culture material , it was concluded that both syndromes were manifestations of the same toxicosis. There was also some evidence that leukoencephalomalacia might be specifically induced by the administration of smaller doses of the culture material to horses over a longer period. The clinical signs of nervous disorder included ataxia, paresis, apathy, hypersensitivity, frenzy, and other locomotory and psychic disturbances. Autopsy showed that the brains were oedematous, and focal areas of liquefactive necrosis were present in the cerebral white matter. In 1 case the malacic areas were not confined to the subcortical white matter but were microscopically visible in the cerebral cortex as well. An histopathological examination of the areas bordering on the malacic areas revealed rarefication of the white matter, perivascular haemorrhages, oedema and cellular infiltration composed mainly of plasma cells and eosinophiles. Many of the macrophages in these areas contained lipofuscin-like granules, but these granules also occurred extracellularly in the neuropil. In the layers of the cortex nearest the malacic areas, satellitosis and neurophagia were commonly seen.
Observations on the transmission, immunology, clinical signs and chemotherapy of dourine (Trypanosoma equiperdum infection) in horses, with special reference to cerebro-spinal fluid
(Published by The Government Printer, Pretoria, 1976) Barrowman, P.R.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
This paper is a record of observations on the transmission and clinical signs of dourine in naturally infected cases of known duration, and of temporal and quantitative aspects of the immune response in blood and cerebro-spina l fluid. Included in the record are observations on the presence of Trypanosoma equiperdutll parasites in these body fluids and methods for their detection. There is evidence that the occurrence of nervous symptoms and lesions in infected horses is associated with the presence of Trypanosoma equiperdunt parasites in cerebro-spinal fluid. The suitability of cerebro-spinal fluid as an environment for the parasite and its relationship with nervous manifestations of the disease are discussed. Observations support the previously reported lesions of peripheral polyneurit is and suggest a possible con•eJation between the consistent position of the nervous lesions and the drainage of cerebro-spinal fluid containing the parasite. Chemotherapy with an experimental drug MSbE was used with varying results in 4 horses at different stages of infection.
Ixodes (Afrixodes) bakeri Authur & Cliford, 1961 (Acarina : Ixodidae): description of the male and immature stages from rodents and insectivores and notes on its biology in South Africa
(Published by The Government Printer, Pretoria, 1976) Walker, Jane B.; Clifford, C.M.; Keirans, J.E.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
The male, nymph and larva of Ixodes (A.) bakeri are described and illustrated with line drawings and scanning electron microscope photographs. This species was originally described from 1 female from Otomys sp., Nyika Plateau, Malawi. The present material consists of 28 collections from insectivores and 19 collections from rodents, Van Riebeeck Nature Reserve, Transvaal, plus 1 collection from a rodent in the Jonkershoek Valley, Cape Province, Republic of South Africa. Its biology in South Africa is also discussed.
Studies on schistosomiasis. 8. The influence of age on the susceptibility of sheep to infestation with Schistosoma mattheei
(Published by The Government Printer, Pretoria, 1976) Van Wyk, Jan Aucamp; Van Rensburg, L.J.; Heitmann, L.P.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
Twenty-eight Dorper wethers, allocated according to age into 4 groups of 7 animals each, and 1 group of 7 Merino wethers, were compared for susceptibility to Schistosoma mattheei infestation. The group mean ages of the Dorper sheep varied from 5-61 months and their live mass from 25-66 kg, while the Merinos were 8 months old and had a mean mass of 19 kg. Despite the marked differences in the age and live mass of the Dorper sheep and the inclusion of 2 breeds in the experiment, no statistically significant differences were found in cercariae which failed to penetrate the sheep the mean percentage development of cercariae to adult worms, worm distribution in the mesenteric and gastric radicles of the portal vein and the pulmonary arterial system, and worms not removed by perfusion. Significant differences between groups (5% significance level) were found, however, in the number of worms recovered from the hepatic portal system, and in the worm sex ratio. On 3 occasions the total number of eggs excreted per female schistosome in the mesentery per 24 hours differed significantly between groups, but each time a different group or groups of sheep were responsible for the variation which was probably due, therefore, not to the age or breed of the sheep, but to daily variations in individuals. Highly significant differences occurred in the infectivity of the 6 cercarial pools used for infestation in spite of standardized collection and handling of the cercariae. Possible reasons for this are discussed and a solution suggested. Frequent egg counts (5 per sheep per week) were done during the first 25 days of patency, until the sheep were slaughtered. Schistosome ova were detected in the faeces of only 1/18 sheep examined on Day +43 after infestation, and 3/17 on Day +44, whereafter this increased rapidly to 15/34 on Day +45, 25/33 on Day +46, etc. A highly significant correlation was found between the total worm egg excretion in the faeces of the sheep per day and the numbers of female schistosomes in the mesentery, especially shortly after the onset of egg production.
The isolation of Mycoplasms synoviae from chickens with infectious synovitis and air-sacculitis in the Republic of South Africa
(Published by The Government Printer, Pretoria, 1976) Buys, S.B.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
Mycoplasma synoviae was isolated from the trachea of chickens showing either typical infectious synovitis lesions or air-sacculitis. M. synoviae was identified by means of the direct plate fluorescent antibody technique and its growth-dependence on nicotine-amide-adenine dinucleotide. This is the first documented report on the isolation and identification of M. synoviae in the Republic of South Africa.
Immunization of mice and calves against Salmonella dublin with attenuated live and inactivated vaccines
(Published by The Government Printer, Pretoria, 1976) Cameron, Colin McKenzie; Fuls, W.J.P.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.; De Kock, V.E.
Previous findings, viz. that mice can be successfully immunized against infection with Salmonella dublin with either live or inactivated vaccine, were confirmed. Immunity lasted for at least 12 weeks in mice which had been immunized with inactivated alum-precipitated vaccine. The immunogenicity of inactivated vaccine gradually decreased on storage at 4ºC, but this was only detectable if a single injection was used for immunization: 2 injections virtually eliminated this phenomenon. The immunogenicity of live vaccine in mice was not enhanced by levamizole or the simultaneous injection of inactivated organisms. Both live and inactivated vaccines provided immunity in calves. A single injection of lyophilized vaccine, prepared from live rough Salmonella dublin strain (HB 1/17), protected 3 out of 6 calves, while 2 injections of a formalin-inactivated, alum-precipitated vaccine, containing 1% packed cells of S. Dublin strain 2652 V, protected 5 out of 6 calves against intraduodenal challenge with 2 x 10⁹ S. Dublin strain 2652 V. Two calves which had been immunized with an inactivated oil adjuvant vaccine were also solidly immune to this challenge. Serum antibody response in calves was poor when measured by the tube agglutination and the haemagglutination tests. Similarly, the sera had only marginal protective values when tested by means of a passive protection test in mice. Antibody titres alone are not a valid measure, therefore, for the immune status of immunized animals.

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