138
VACCINATION AGAINST RINDERPEST
[Vol. XXV, Part II,
Fig. 4 shows the composite charts of the two groups of lambs. An examination
of these charts indicates that the average reaction of 10 days (102.48°F) is slightly
more marked in the scarification group as compared to the subcutaneous group in
which the corresponding figure is 102.16°F. The difference of 0.32°F is not signi
ficant. The vaccinated animals showed dullness and loss of appetite. There is
no evidence of any delay in the exhibition of thermal reaction in animals vaccinated
by the scarification method. Two animals, one from the scarification and the other
from the subcutaneous group, died as a result of reaction. The reaction was there
fore severe.
Lall [1947] reported that sheep of Lohi breed, particularly the lambs, were the
most susceptible and reacted like goats. He mentioned that the use of anti-rinderpest
serum along with ' Goatis ' was necessary in this breed. Observations recorded in
the above experiment are in conformity with his findings.
Immunity test. In order to assess the immunising value of the two methods of
vaccination, a comparative test was conducted on animals immunised by the above
methods at the end of one year after vaccination. Twelve animals consisting of
three Hissari, three Lohi and three Bikaneri female lambs and three Betal goats
were included in each group. Two kids were kept to act as controls to ensure the
potency of the testing virus. Three c.c. of fresh rinderpest goat blood virus obtained
from Punjab Veterinary College, Hissar, was given to each of the animals under
experiment, and the controls. The animals under test were allowed to mix freely
with the reacting controls so that they were exposed to all possible outside chances
of infection. Morning temperature of all the animals was recorded for 10 days
following virus inoculation. Out of 12 animals vaccinated by scarification method,
three (Hissari lamb No. 749, Bikaneri lamb No. 293 and Betal goat No. 583) showed
thermal reaction on the fourth day, the temperature going as high as 105°F. The
goat also exhibited diarrhoea on the fifth day. In the second group of animals
immunised by subcutaneous method, only one (Hissari lamb No. 737) showed a break
down in immunity. Appendix shows reaction following vaccination and subsequent
to challenge dose with virulent virus in the experimental animals.
The four animals which showed breakdown in immunity were aged 10 months
to 1⅓ years at the time of vaccination. These can be classified into two groups, (A)
animals which showed mild reaction after vaccination, these were female lambs
Hissari No. 737 and 749, and (B) animals which showed appreciable reaction following
vaccination but did not develop immunity. These were female lamb Bikaneri
No. 293 and Betal goat No. 583. The breakdown in immunity in animals under
(A) above may be attributed to inadequate absorption of the virus but the breakdown
in immunity in animals under (B) cannot be satisfactorily explained except that it
may be said that the reaction in these animals following vaccination was due to some
factor other than rinderpest virus reaction. Simultaneously it is interesting to
observe that out of 24 animals used in the immunity test, six animals, female lamb
Hissari No. 748, female lamb Lohi No. 69, 72, 65, 64 and female lamb Bikaneri
No. 254, although showed mild reaction anologous to that observed in animals
under (A), withstood the challenge dose quite well.