March, 1953]
J.
M. LALL AND N. C. SEN
31
if revaccination in addition to intensifying the initial resistance, could also lengthen
its duration. These workers were of the opinion that the degree of resistance set up
in cattle was correlated with the virulence of the vaccinating strain of vole bacillus
for its natural host. This fact would necessitate that any strain used for vaccine
purposes will have to be maintained at a high level of virulence by repeated passage
through its native host. They have encountered one strain of vole bacillus (G.
564), which could set up a fatal infection in calves. A severe transient lameness
following inoculation affected a proportion of the animals and the joint lesions
which were found in such cases resembled those generally seen in joints in serum
sickness, allergy and anaphylaxis. Utmost care is therefore necessary in the selec-
tion of a strain of the vole bacillus for vaccine purposes. However, nothing was
noted by them, which would contra-indicate the use of strain LV 285.
The histopathological studies carried out by Young and Paterson revealed
that changes pathogonomic of tuberculous infection, which followed the intravenous
inoculation of vole bacilli, were mainly confined to the lungs and thoracic glands.
They reached their maximum about 28th day and had undergone resolution by the
84th day.
Young and Paterson have also studied the changes which occur in the cells of
the reticulo-endothelial system following vaccination, and these studies are very
helpful in deciding the optimal time and dosage for re-vaccination. This rich and
virgin problem provides a very important and useful field for further investigation.
Lall [1952]* inoculated intravenously two tuberculin and johnin negative
kids with 10 mg. of 15 days old culture of vole bacilli (strain LV285) and another two
subcutaneously with 3.0 mgm. of the same culture suspended in 3 ml. of olive oil
along with 150 mgm. of sterile powdered stone. The kids were about a month old
at the time of receiving the culture.
All the kids were subjected to D.I.D. tuberculin and johnin tests after 11 weeks
of the vaccination. None of these gave any reaction to johnin but with tuberculin
the reactions were moderate in the kids injected intravenously, while the ones in-
jected subcutaneously showed typically good reactions. (On account of repeated
sub-culture the strain LV 285 used in the above experiment had become of sub-
standard virulence).
DISCUSSION
It is abundantly clear that the vole bacillus does produce a resistance to sub-
sequent infection with virulent tubercle bacilli in animals and that vaccination with
this organism will find a useful place in any scheme directed towards the control or
eradication of this scourage from the livestock of a heavily infected country. Now,
the question is not whether this vaccine can be used but as to how it can be employed
to the best advantage. However, it will not be a sound policy to adopt a new
vaccine, unless it possesses some distinct advantages over B.C.G. which is already
being used and so before advocating the use of vole vaccination, it seems rational
to compare its merits as an antigen with B.C.G., which is now universally applauded,
has been in use over a score of years and has stood the test of times and with which
*Unpublished work.