1958 Onderstepoort Journal of Veterinary Research, Volume 27, Number 4, 1958

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Contentes Pages: Onderstepoort Journal of Veterinary Research, Vol ??, 19??

CONTENTS

*Volume 27: Number 4*

The Fiftieth Anniversary of the Onderstepoort Laboratories as a Veterinary Research Institute	Alexander, RA	462

Immunological types of horsesickness virus and their significance in immunization	McIntosh, BM	465

Strain 19 Brucella vaccine: V. Mass production in the Brucella Vortex Aerated Culture apparatus	Van Drimmelen, GC	539

The protection of sheep against blowfly strike. V. The duration of protection of certain insecticides under field conditions	Stampa, S, Fiedler, OGH & Du Toit, R	549

Studies on sucking lice of African mammals. Part I. Revision of certain doubtful Linognathus species	Fiedler, OGH & Stampa, S	583

Zoological Survey of the Union of South Africa. Tick survey. Part X. Distribution of Margaropus winthemi, the winter horse tick	Theiler, G & Salisbury, LE	599

Zoological Survey of the Union of South Africa. Tick survey. Part XI. The distribution of Otobius megnini, the spinose ear tick	Theiler, G & Salisbury, LE	605

The utilization of the phosphorus from an aluminium-iron rock phosphate. I. By the rat	Reinach, N & Louw, JG	611

The utilization of the phosphorus from an aluminium-iron rock phosphate. II. By sheep	Reinach, N & Louw, JG	617

Author index		625

Subject index		628

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Now showing 1 - 11 of 11

Zoological Survey of the Union of South Africa. Tick survey. Part X. Distribution of Margaropus winthemi, the winter horse tick
(Published by The Government Printer, Pretoria, 1958) Theiler, Gertrud; Salisbury, Lois E.; Alexander, R.A.; Clark, R.; Louw, J.G.; De Kock, V.E.
(1) The distribution of M. winthemi is given in terms of political divisions as well as in terms of vegetational coverage. (2) M. winthemi is a winter tick, 80 per cent of the records of its presence are for the winter months May to August. (3) From the data available it is difficult to establish the factors limiting the distribution of the tick. (4) The absence of winter collections from many areas has prevented a complete picture of the distribution of the tick being drawn.
Subject index
(Published by The Government Printer, Pretoria, 1958) Anonymous; Alexander, R.A.; Clark, R.; Louw, J.G.; De Kock, V.E.
Author index
(Published by The Government Printer, Pretoria, 1958) Anonymous; Alexander, R.A.; Clark, R.; Louw, J.G.; De Kock, V.E.
The utilization of the phosphorus from an aluminium-iron rock phosphate. II. By sheep
(Published by The Government Printer, Pretoria, 1958) Reinach, Norman; Louw, J.G.; Alexander, R.A.; Clark, R.; Louw, J.G.; De Kock, V.E.
The availability of the phosphorus in "bone pellets" and aluminium-iron rock phosphates was compared with bone meal. In evaluating the products, inorganic phosphorus content of the blood, live weight gains, phosphorus retention, X-ray photographs and the pathological and chemical examination of the bones of the sheep were used as criteria. From the overall results thus obtained it can be concluded that: (i) "Bone pellets" are as efficient as bone meal as a source of phosphorus. (ii) Aluminium-iron rock phosphate is practically useless in this respect and cannot replace bone meal in animal nutrition.
The utilization of the phosphorus from an aluminium-iron rock phosphate. I. By the rat
(Published by The Government Printer, Pretoria, 1958) Reinach, Norman; Louw, J.G.; Alexander, R.A.; Clark, R.; Louw, J.G.; De Kock, V.E.
The availability of the phosphorus in two samples of an aluminium-iron rock phosphate has been determined in the rat. In evaluating these products live weight gains, the ash content of the femurs and total phosphorus retention have been used as criteria. The rock phosphate was found to be a poor source of phosphorus.
Zoological Survey of the Union of South Africa. Tick survey. Part XI. The distribution of Otobius megnini, the spinose ear tick
(Published by The Government Printer, Pretoria, 1958) Theiler, Gertrud; Salisbury, Lois E.; Alexander, R.A.; Clark, R.; Louw, J.G.; De Kock, V.E.
1. The distribution of O. megnini is given in terms of political divisions, as well as in terms of vegetational coverage. 2. The factor limiting its distribution appears to be high rainfall. The tick has probably not yet been introduced into all areas of the Transvaal. 3. Seven day dipping has been shown to control the tick in some districts. 4. No seasonal periodicity was observed.
Studies on sucking lice of African mammals. Part I. Revision of certain doubtful Linognathus species
(Published by The Government Printer, Pretoria, 1958) Fiedler, O.G.H.; Stampa, S.; Alexander, R.A.; Clark, R.; Louw, J.G.; De Kock, V.E.
The protection of sheep against blowfly strike. V. The duration of protection of certain insecticides under field conditions
(Published by The Government Printer, Pretoria, 1958) Stampa, S.; Fiedler, O.G.H.; Du Toit, R.; Alexander, R.A.; Clark, R.; Louw, J.G.; De Kock, V.E.
A large number of field trials under close supervision was conducted in the blowfly areas of the Karoo to investigate certain biological aspects of blowfly strike as well as the protection afforded to sheep by the insecticides Diazinon, Dieldrin, Aldrin and B.H.C. under natural conditions. (1) The biological factors rendering sheep susceptible to blowfly strike are reviewed. (2) Observations on the development of strikes in sheep treated with an insecticide as compared with unprotected animals are reported. (3) The larvicidal value of the compounds tested are discussed, as well as the factors influencing the duration of protection afforded by them. (4) Dusts and wettable powders gave longer protection than emulsions in sheep with clean and dry crutches, whereas emulsions and wettable powders gave better results in soiled sheep. (5) The protecting agent must be evenly distributed throughout the vulnerable areas of the fleece right down to skin level to ensure the maximum degree of protection. (6) No significant difference in duration and degree of protection was observed with quantities of between 0•45 and 2•85 gm. of the active ingredient per crutch region. This is probably due to this factor being overshadowed by others. (7) Insecticides gave better protection when applied to long wool than to short wool. The crutching of soiled breeches is discouraged, therefore. (8) Soiled crutches exercise an influence upon the uniformity of the application and, consequently, upon the duration and the degree of protection. This is particularly evident in the case of B.H.C. No significant differences could be detected between Diazinon, Dieldrin and Aldrin. (9) All insecticidal compounds afford a considerably shorter period of protection on young lambs than on adult sheep with an equal or even shorter length of wool. (10) The incidence of blowflies (fly population pressure) exercises the most significant influence upon duration of protection afforded by any of the insecticides. The relationship between fly population pressure and duration or protection follows the equation of a hyperbola. (11) The duration of protection afforded by Diazinon, Dieldrin and Aldrin showed no significant differences under equal conditions, whereas B.H.C. was markedly inferior. (12) The Mule's operation affords adequate protection as long as the incidence of flies is low and the wool fairly short. With higher fly population pressures the resistance of "muled" sheep to fly strike decreases rapidly.
Immunological types of horsesickness virus and their significance in immunization
(Published by The Government Printer, Pretoria, 1958) McIntosh, B.M.; Alexander, R.A.; Clark, R.; Louw, J.G.; De Kock, V.E.
1. A brief review is given of the epizootiology of horse sickness, the antigenic plurality of the virus strains, and the history of the control of the disease by immunization. 2. It is often not possible to isolate virus directly in mice from cases of horse sickness in immunized horses. 3. The usefulness of the ferret, and possibly the dog, for the isolation of virus from such horses was demonstrated. 4. Immunological studies on 42 mouse-adapted horsesickness virus strains were conducted. 5. For these studies an intracerebral neutralization test in mice was used. Hyperimmune sera from rabbits were mainly used in the tests. 6. Cross-neutralization tests with rabbit antisera were carried out on the eight virus strains included in the present vaccine issued from Onderstepoort and 16 strains recently isolated from cases of horsesickness in immunized horses. 7. This series of tests showed that the virus strains could be grouped into seven immunological types. It was also evident that some immunized horses become infected with strains of the same immunological type as the vaccine strains. 8. Using type rabbit antisera a further series of neutralization tests was conducted on 18 other horsesickness virus strains. These tests showed that these strains also could be grouped within the same immunological types. 9. It was shown that four recently isolated strains belonging to the same immunological type were not represented in the present Onderstepoort vaccine. 10. A limited number of neutralization tests with ferret antisera supported the antigenic grouping as revealed by the tests with rabbit antisera. 11. A serological study of sera obtained from eight immunized horses reacting to horsesickness was made. 12. Viruses isolated from each of these horses were included in the cross-neutralization tests which showed that seven of these viruses are of the same immunological type as the vaccine strains. 13. High level antibody against all the vaccine strains was shown to be present in sera from seven horses. 14. It was concluded that these particular failures in immunity were not due to inadequate immunization but were apparently the result of slight antigenic differences between the infecting virus and the vaccine strains. 15. The significance of the antigenic grouping based on the mouse neutralization test to immunity in equidae is discussed. 16. It is believed that this antigenic grouping has a definite relationship to immunity in these animals.
Strain 19 Brucella vaccine: V. Mass production in the Brucella Vortex Aerated Culture apparatus
(Published by The Government Printer, Pretoria, 1958) Van Drimmelen, G.C.; Alexander, R.A.; Clark, R.; Louw, J.G.; De Kock, V.E.
The vaccine organism Brucella abortus strain 19 has been cultured in bulk in 72 litres of liquid medium aerated in a vortex system in a stainless steel culture vessel of 250 litre capacity. The lay-out and operation of the apparatus are described and results of a series of batches produced are given. The differences between various production methods are briefly presented.
The Fiftieth Anniversary of the Onderstepoort Laboratories as a Veterinary Research Institute
(Published by The Government Printer, Pretoria, 1958) Alexander, R.A.; Alexander, R.A.; Clark, R.; Louw, J.G.; De Kock, V.E.

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