Research into contagious abortion of cattle, sheep and goats. Brucellosis in India. I. The occurrence of brucellosis in India. II. Comparative susceptibility. III. The dissemination of brucellosis in India. IV. Bacteriology of Indian strains. V. Diagnosis. VI. Brucellosis and public health. VII. The control of brucellosis in India. VIII. Specific abortion, other than brucellosis. IX. Non-specific abortion
Polding, J.B.
Indian Journal of Veterinary Science and Animal Husbandry 18(3): 115-193
1948
ISSN/ISBN: 0019-5715 Document Number: 648301
I. A detailed outline is given of the distribution of brucellosis in India. Endemics are common in several places and they account for 1 to 5% of the abortions. Brucellosis was most prevalent where farms were abundant. The disease was commin in areas of heavy rainfall. The majority of strains isolated from organised farms were of pure European type (Brucella abortus), while all Brucella strains isolated from villages differ in their characteristics from B. abortus.-II. Taking the figure for country cows as unity, the susceptibility index for cross bred cows was 7 and for indigenous stock cohabiting with crosses it was 2.5. The susceptibility among cross-bred cows increased with the increase of European blood. In military farms the abortion rate was 1.4% for indigenous stock, whereas with 1/2 grade (Fresian-India) it was 3% and 7/8 grade 7.3% . Buffaloes were less susceptible to brucellosis than country cows, and in buffaloes cohabiting with cross-bred cows the susceptibility index was 1.5. In sheep the incidence of the disease was slight, but the goat was more susceptible. In cows and buffaloes abortion usually occurred during the 1st to 6th pregnancies, the incidence decreasing with the increase in the number of pregnancies. The age at which fetus was aborted varied from 3 to 9 mos., the chances of incidence increasing with the advance of pregnancy.-III. Sunshine and dryness are inimical to Brucella microbes. Congestion is only of secondary importance in the spread of brucellosis when there is good sunlight. Humidity and heavy rainfall play an important role in the dissemination of the disease.-IV. 49 strains of Brucella were examined for their virulence (white mice tests), antigenic structure, CO2 requirements at isolation, H2S elimination and inhibitory action of dye media (basic fuchsin and thionine). About 40% of all Indian field strains had typing characteristics intermediate between B. abortus and B. melitensis, and it has been adduced that this was an indigenous strain.-V. The theory and practice of the standard tube agglutination test are outlined and the application of the test on an all-India basis discussed. The test is described as the most critical and uniform that can be deviced for routine work.-VI. Melitensis fever is now rarely encountered in India. This is attributed to the universal practice of boiling milk, and also to the fact that the occurrence of brucel losis in sheep and goats in India is light. The infection referred in the earlier records was introduced into localized areas by troop-movements from Malta.-VII. Methods of controlling brucellosis by hygienic measures and vaccination are discussed. Hygienic segregation if practicable when the frequency of abortion is less than 5% per annum, where the disposition of the farm lends itself to cleanliness, where frequent purchases of in-calf animals from endemic centers are not made, when it is possible to disperse the live-stock for grazing over a wide area, and when climetic conditions are favorable. An outline is given of a simple method of segregation which can be easily adopted. In the 2d sub-section a study is reported of the behavior of Cotton's strain No.19, McEwen's Nos. 45, 45(6) and 45(20), and Huddleson's No.805 vaccines under Indian conditions. Temp. of storage (above 5°C), age and agitation cause Brucella vaccines to deteriorate. At temps. higher than 70°F the cumulative effect of all these factors is considerable. The 5 vaccines named above were to a varying degree, less virulent than India-field or type-specific strains. McEwen's No. 45(20) and Cotton's No. 19 on account of their virulence can be used with safety when it is desired to use a single strain. A technic is recommended for the prepn. and issue of Brucella vaccines which consists in sowing the vaccine strain on liver agar (pH 6.8-7) and incubating for 48-72 hrs. at 37°C. The growth is washed off in a small measured quantity of optimum vehicle (25 ml. per Roux flask). The yield from sufficient flasks is pooled (one flask gives 100-150 ml. of finished vaccine) and tested to ascertain the dilution factor required to give a density of tube 5 or 6 on Brown's scale. Precautions to be observed in using this vaccine are described. As a control measure it is recommended that vaccination need only be practiced when the abortion rate exceeds 5% per annum, and conditions adverse to hygienic control exist.-VIII. In a study of the specific primary genital infections, apart from Brucellosis, which cause abortion, it was found that neither trichomoniasis, listerellosis, vibrio infections, or Salmonella infections were responsible. Preliminary observations suggest a new bacterium which may be the cause of abortions in goats.-IX. The incidence of non-specific bovine abortion varies from 0.5% to 2% per annum. In cows an attack of rinderpest and hemorrhagic sept-icemia appear to be the inciting stimulus, the abortion occuring simultaneously in sever al Brucella-free convalescents. There appears, therefore, some ground to believe that otherwise inexplicable abortions could be attributed to previous sickness or physical upset. In buffaloes the rate of non-specific abortion is higher and these animals are known to abort after an attack of a severe fever or systemic disturbance, e.g., rinderpest, anti-rinderpest injn., hemorrhagic septicemia, foot and mouth disease, and chilling during rainfall. In the case of sheep and goats it seems possible that these animals will abort as a result of any disease which seriously impairs their health, e.g., pneumonia, rinderpest or rinderpest pneumonia, contagious pleuro-pneumonia (goats), wah, pox and even parasitic infestation. Goats are known to abort as the result of the slightest interference, sometimes even an intraven. injn.