Browsing by Author "Gourlay, R.N."
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Item The Allergic Reaction in Contagious Bovine Pleuropneumonia(1964) Gourlay, R.N.; East African Veterinary Research Organization, Muguga KenyaSerological diagnosis of Contagious Bovine Pleuropneumonia (CBPP) has been primarily by means of the complement fixation test (CFT), but also to a lesser extent by the slide agglutination serum test (SAST), the slide agglutination blood test (SABT) and the agar gel double diffusion precipitin test (AGT). All these tests, except possibly the slide agglutination tests, require some laboratory facilities and the case of the CFT quite elaborate ones. In addition, all these tests, except possibly the SABT, necessitate the numbering of each animal for subsequent identification. These factors form a serious obstacle to the diagnosis of CBPP in some countries of Africa due to the vast distances between the laboratory and outbreaks of the disease and the lack of communications and transport. The development, therefore, of a simple diagnostic test, along the lines of the tuberculin test, has had a high priority in research programmes on CBPP in East Africa.Item The Antigenicity of Mycoplasma mycoides III-Isolation of Precipitating Antigens from Urine.(1965) Gourlay, R.N.; Palmer, R.F.; East African Veterinary Research Organisation, Muguga, P.O. Box 32, Kikuyu, KenyaPrecipitation of urine with increasing volumes of iso-propyl alcohol, removing the precipitate at each step and deproteinization with chloroform and butanol, produced a number of fractions which gave specific precipitin hands in the agar gel precipitin test when diffused against hyperimmune sheep sera, and which were Molisch positive and biuret negative. The number of precipitin bands produced with the different fractious depended on the amount of alcohol used for the precipitation. In a series of experiments in which the precipitate produced by each volume of alcohol was removed before the next volume of alcohol was added, 1 and 2 volumes of alcohol produced fractions which gave 6 precipitin bands, while 3 volumes produced a precipitate which gave 4 hands or occasionally 5. Precipitates from 4 and 5volumes produced 4 bands, whereas 6 volumes gave only 2 bands. P.1/2/3, the result of precipitation with 3 volumes of alcohol added in one aliquot, gave 6 precipitin bands, whereas P.4/5/6, the result of precipitation with a further 3 volumes of alcohol followed by alternate precipitation with 3 and 6 volumes, gave 2 strong and 2 weak precipitin bands.Item Antigenicity of Mycoplasma mycoides n.-Further Studies on the Precipitating Antigens in the Body Fluids from Cases of Contagious Bovine Pleuropneumonia(1965) Gourlay, R.N.Absorption of antiserum with antigens prepared from various body fluids showed that 87' 5% of the complement fixing antibody was removed from the serum by absorption with antigens prepared from serum, lymph and urine, while almost all the aggluttinating antibody was removed by absorption with lymph, 99' 4 % by absorption with serum and 95% by absorption with urine. The major precipitating antigens were apparently resistant to boiling and the action of trypsin, and were therefore not protein in mature but probably poly saccharide. The minor precipitating antigens were destroyed by boiling and all but one by the action of trypsin, and the majority therefore were probably protein. At least 6 minor precipitately antigens were demonstrated, and apparently they were associated primarily with the organisms. The major precipitating antigens were predominantly extracellular with only small amounts present in the organisms. These major antigens were also elaborated by the organisms when grown in artificial culture medium, and those produced by fully virulent organisms appeared to be identical with those produced by a virulent organisms..Item Artificial Reproduction of Contagious Bovine Pleuropneumonia(1964) Gourlay, R.N.; East African Veterinary Research Organization, Muguga, KenyaThe experimental reproduction of C.B.P.P. in cattle appears to have been resolved, the virulence of the strain used being of importance: where less virulent strains are used, some form of stress appears to be necessary for the development of acute lung lesions. Sheep and goats are susceptible to s/c inoculation but a large inoculum appears to be necessary. Laboratory animals are not susceptible unless the organisms are incorporated in an agar base. It is possible that stress would assist in the adaptation of M. mycoides to these animals. Other than cattle the chick embryo is probably the most useful experimental host. (AS).Item Evaluation of Diagnostic Tests for Contagious Bovine Pleuropneumonia(1964) Shifrine, M.; Gourlay, R.N.; East African veterinary Research OrganizationThe slide agglutination serum test in conjuction with agar gel diffusion tests for antigen and antibody 100% of cattle naturally infected with contigious bovine pleuropneumonia. The complement fixation test, however, failed too detect 6% of these cattle.Item Fermentation of Glucose by Mycoplasma Mycoides and its Effect on Viability(1966) Gourlay, R.N.; MacLeod, A.K.; East African Veterinar Research. OrganizationSince broth culture vaccine prepared from the TI avianised strain of Mycoplasma mycoides var. mycoides (Piercy and Knight, 1956) at the forty-fifth egg passage, was first prepared at Muguga in July 1962 and subsequent large-scale production in July 1964, it has been grown in modified Newing's tryptose broth (Gourlay, 1964). During 1964 a few batches of broth culture vaccine were prepared from the T2 avianised strain of M. mycoides (Piercy and Knight, 1956) at the thirty-third egg passage. These batches were produced in a manner identical to that used for the large-scale production of TI broth culture vaccine (Brown, Gourlay and MacLeod, 1965). During routine titrations of the vaccine it was noticed, however, that the T2 vaccine did not maintain its titre of viability as well as the TI vaccine and it was decided to investigate the reasons for this. Investigation showed that the loss of viability was associated with excessive lowering of the pH, which was also associated with the glucose content of the medium; furthermore, different strains of M. mycoides varied in their ability to ferment glucose. The following paper gives details of these studies.Item Further Studies on the Allergic Reaction In Contagious Bovine Pleuropneumonia(1965) Gourlay, R.N.; Palmer, R.F.; East African Veterinary Research Organization, Muguga, KenyaAn earlier paper (Gourlay, 1964) recorded the preparation of an allergic antigen and its use, both experimentally and in the field, for the diagnosis of Contagious Bovine Pleuropneumonia (CBPP). This antigen contained a certain amount of insoluble material that possessed activity. The present paper describes further work done in an effort to produce a more soluble antigen, the use of a more virulent strain of Mycoplasma mycoides for antigen production and its use experimentally and in the field.Item Growth Inhibition and "Neutralization" of Mycoplasma Mycoides by Immune Bovine Serum I. Development of a Liquid Medium Test(1967) Gourlay, R.N.; Domermuh, C.H.In 1954, Edward and Fitzgerald! reported that when antisera to various species of pleuropneumonia-like organisms (Mycoplasmataceae) were incorporated in culture medium, growth of the homologous organism was inhibited. Complement was not required for this inhibition. They further suggested that there was a similarity between inhibition of growth of mycoplasma and virus neutralization. Bailey, Clark, Felts and Brown2 used an inhibition-of-growth test based on that of Edward and Fitzgerald to study the growth-inhibitory properties of specific antibody on Mycoplasma hominis. Huijsmans-Evers and Ruys3 described a method of inhibiting human genital mycoplasma on solid medium by application of antiserum-saturated paper discs, and later Clyde4 modified and extended this method to identification of mycoplasma isolated from the human pharynx and from tissue culture.Item The Immediate Type Allergic Skin Reaction in Contagious Bovine Pleuropneumonia(1965) Shifrine, M.; Gourlay, R.N.; East African Veterinary Research Organization, Muguga, Kenya.Proteins extracted from Mycoplasma mycoides by hot phenol or trichloracetic acid gave larger delayed allergic reactions in immune cattle than proteins extracted by cold phenol or ammonium sulfate. The addition of a paraffin-lanolin adjuvant to the proteins extracted by hot phenol resulted in an enhanced delayed reaction in immune cattle when inoculated s/c or i/d. Unfortunately, this material produced large reactions in some negative cattle when inoculated i/d. When inoculated s/c it still produced reactions in some negative cattle, but they were less severe. The addition of corn (maize) oil as an adjuvant was more satisfactory. When inoculated i/d it gave only a small reaction in a proportion of negative cattle and appreciably enhanced the reaction in immune cattle. Lipopolysaccharide-protein, extracted with hot phenol from cells of M. mycoides, induced an immediate allergic reaction in cattle previously inoculated with M. mycoides. The activity of this material was reduced after extraction with chloroform/methanol, or after periodate oxidation, but was unaltered after treatment with trypsin and papain, or after boiling. The lipopolysaccharide, therefore, appears to be responsible for the immediate allergic reaction. This material was not specific as it contains antigenic components in common with another bacterium isolated from cattle.Item Lyophilisation of Mycoplasma Culture Vaccine(1964) Palmer, R.F.; Gourlay, R.N.; East African Veterinary Research Organization, MugugaLiquid culture vaccines against contagious bovine pleuropneumonia are used in various parts of Mrica and Australia. Lyophilisation provides an obvious method of overcoming the poor keeping properties of these vaccines and furthermore, by lyophilisation a properly tested and standardised product can be issued and stocks accumulated to meet sudden heavy demands. A series of experiments were undertaken, using two culture vaccine strains of M. mycoides, to compare various suspending media, two methods of lyophilisation and different reconstituting fluids. A reconstitution curve using the most suitable of these methods was also prepared.Item Passive Transfer of Immunity and Formation of Lung Lesions in Cattle following Intravenous Inoculation of Antibody and Mycoplasma(1966) Gourlay, R.N.; Shifrine, M.; East African Veterinary Research Organisation, Muguga, P.O. Box 32, Kikuyu, KenyaIntravenous inoculation of hyperimmune or immune bovine serum into cattle 24 hours before intravenous inoculation of the virulent Gladysdale strain of M. mycoides transferred passive immunity as judged by the absence of oedematous reaction of Willems at the mycoplasma inoculation site. Lung lesions of CBPP developed in two cattle that had received hyperimmune or immune serum before the intravenous inoculation of mycoplasma, but also a small lesion developed in one animal not previously inoculated with serum.Item A solid medium test for measuring growth inhibition and neutralization of Mycoplasma mycoides by immune Bovine Serum(1967) Domermuth, C.H.; Gourlay, R.N. ; East African Veterinary Research Organization, MugugaThe growth of Mycoplasma mycoides var. mycoides was inhibited and neutralized by immune serum from cattle which had recovered from infection with M. mycoides. Although mycoplasmal neutralization is not necessarily the same as virus neutralization, it is suggested that this terminology be retained since it is accepted and is descriptively appropriate. The effect of immune serum on colony growth was determined by incubating test serum in plastic cylinders on nutrient agar with pre-incubated microscopic M. mycoides colonies. Optimal inhibition and neutralization occurred when serum and colonies were incubated at 30° before final incubation at 37°. Inhibition of growth and neutralization also occurred at 37° and 21° inhibition, but no neutralization occurred at 5°Item The Use of Embryonated Chicken Eggs for the Study of Immunity to Mycoplasma mycoides(1966) Gourlay, R.N.; Shifrine, M.Sir, -The only host available at present, other than cattle, Of experimental studies on contagious bovine pleuropneumonia (CBPP), is the chicken embryo; CBPP has not been transmitted as yet, in the true sense, in laboratory animals.Item The Virulence and Viability of Mycoplasma mycoides Strains 111 Chicken Embryos from Normal and Immunized Hens(1968) Shifrine, M.; Gourlay, R.N.The Gladysdale strain was inoculated into immune and normal chicken embryos and there was a decrease in the number of organisms in the immune embryos, from the 4th day after inoculation, when compared with the normal embryos. Sera from immune hens possessed agglutinating and growth inhibiting antibodies, but yolk extracts from these hens rarely contained agglutinating antibodies. The immunity possessed by embryos persisted at least 17 weeks after immunization of the hens.
