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Contagious Abortion of Cattle, Sheep and Goats
[VOL. XVIII, PART III
Technical notes
For general information the following brief technical notes are appended.
Routine cultures : Unless otherwise specified all day-to-day cultures and the monthly sub-cultures
of the type collection have been made on liver agar pH 6-6 to 6-8 [Huddleson 1939]. Up to the
present, it has not been possible to preserve cultures by desiccation in vacuo, other than experimental-
ly. However, with the recent installation of the necessary apparatus at the Imperial Veterinary
Research Institute it is hoped that the type collection can be so disposed in future.
Isolation cultures : As long as tryptose has been available cultures intended for Brucella isolation
have been made on tryptose (Difco)* agar or broth, (pH 6.9) otherwise liver media (pH 6.6 to 6.8)
have been used.
Routine tests : Before use, stock Brucella strains have always been tested for roughness; unless
so specified, rough strains have not been used.
Dye media : Crystal-violet-liver (or tryptose) agar (crystal violet 1/700,000) has been used for
primary isolation, when there has been risk of much contamination. In this and in dye media in-
hibition tests Grubler dyes have been used.
Technique of isolation : When several strains have been isolated from the same herd, subsequent,
attempts have been made by cultural methods only. When no previous strains have been obtained,
culture and guinea-pig inoculation have both been used. The actual field technique used in securing
specimens has been described elsewhere [Polding 1943].
SECTION V. DIAGNOSIS
Amongst the several recognized ways of diagnosing Brucellosis, by far the most popular is the
blood serum agglutination test. The intradermal test is the only other method receiving practical
attention and great claims are made for it in the U.S.S.R.; but the double intradermal test entails
the handling of animals thrice and a halt of four days to read a single test. The agglutination test,
on the other hand, requires the handling of animals once and a halt of a few hours ; so that in the
difficult touring conditions of India, and in dealing with the wild indigenous animal, the former
method is much less practicable than the latter.
In the present work, therefore, the agglutination reaction has been exclusively used, and, in
the interests of uniformity, an effort has been made to introduce a standard all India tube agglutination
test.
The standard tube agglutination test
Experience in Europe has incontravertibly shown that it is often far from easy to standardize
a biological reaction, even one so uncomplicated as a straight agglutination test. It has been shown
for example that an antigen prepared at one institute may differ considerably from that made at
another although the same technique and bacterial strains are used. The first step in standardiza-
tion, therefore, is the exclusive universal use of a single antigen prepared as far as possible by the
same staff and in the same laboratory. In consequence, a carefully prepared antigen has been offered
to the provinces by the Indian Veterinary Research Institute at production cost only. Obviously,
such an antigen should be used in the particular modification of the technique of agglutination for
which it is designed, and the interpretation of the test's results should be in accordance with a pre-
determined schedule. A leaflet governing the use of the antigen is, therefore, obtainable from the
Indian Veterinary Research Institute and has also been published [Polding 1943].
The tube agglutination test, as recommended by the Indian Veterinary Research Institute is
believed to be the most critical and uniform that can be devised for routine work. Its use is urged,
therefore, when an accurate diagnosis is required, that is to say, when a drastic decision, such as the
disposal or slaughter of animals, depends on its result, or at other times when exact information is
required.
* Baird & Tatlock Ltd: London.