32
VOLE
VACCINATION
[Vol. XXIII, Part I,
a number of laboratory as well as field trials in animals under carefully controlled
conditions have been carried out. As for other methods of vaccination, e.g. Behring's
method of double inoculation with live-vaccine, Klimmer's vaccine, known by the.
trade name of antiphymatol, Heyman's method, these can perhaps be straight-
away ruled out in any comparison with vole vaccination, as these, after a few trials
here and there, were abandoned, or at any rate did not become popular, either be-
cause the resistance produced was not significant or because they were not safe
from the public health point of view.
Comparison between vole vaccination and B.C.G. can be well made from five
aspects, viz. safety, local reaction, tuberculin test conversion rate, degree of induced
resistance and stability of virulence.
Safety. It has been established beyond doubt that B.C.G. is quite safe. As
regards, vole bacillus too, the published reports indicate that it does not cause
progressive disease in animals unless given in very large doses. Griffith and Dalling,
[1940] used doses of 10 mgm intravenously and 80 mgm. intramuscularly in cattle
without producing progressive disease. They also found that the vole bacillus
was not virulent for guinea-pigs. Sahai [1943] proved the almost complete in-
nocuousness of this organism for monkeys, and also established that the bacilli
were not excreted through the milk of vaccinated cows. Wallgren [1945] showed
that vole bacilli are avirulent to guinea-pigs and human beings. Wells' experience
with the vole bacillus injected into 121 human beings, in some instances in a dosage
higher than that needful or desirable for immunising purposes, suggests that it does
not produce anything other than localised disease. However, the experience of
Young and Paterson [1949] with one strain of vole bacillus, G 564, which could set
up a fatal infection in calves, makes us feel very seriously that great care is necessary
in the selection of a strain for vaccine purposes. Of course, nothing has been observed
so far by any worker, which would contra-indicate the use of strain LV 285.
Young and Paterson [1949] found that the induced resistance had a co-relation
with the degree of virulence of the vole strain. That being so, it opens
a field for investigation as to whether a vaccine consisting of ultraviolet
killed strain G 564 will form a good antigen. Some work in this connection has
already been carried out by Paterson, Crombie and Coles [1949] and the results
reported are encouraging.
Local reaction. The local reactions obtained with the vole bacillus seem to be
entirely comparable to those with B.C.G. enlargement and ulceration of the lymph
glands seen after subcutaneous or intradermal injection of B.C.G. [Kereszturi,
Rosenberg and Park, 1937; Wallgren, 1923] have not been observed by Wells [1946]
after injection of the vole bacillus in human beings.
Tuberculin test conversion rate OR Allergy to tuberculin. It seems that tuber-
culin allergy following vaccination with the vole bacillus is greater and occurs earlier
than that following B.C.G. vaccination [Griffith and Dalling, 1940; Wallgren, 1945].
In order to appreciate the above, it will be perhaps necessary to describe briefly
the relationship between allergy and immunity, which of recent years is a subject
under active discussion. Two opposing views are being put forward, each based on
circumstantial evidence. The theory that allergy is an essential part of the mecha-
nism of acquired resistance is disputed by Rich, according to whom no part is