210
Against Bovine Pleuropneumonia Vaccination
Out of the five vaccinated cattle, one bullock died of distomatosis and anaemia in July 1943
and a cow strayed away in May 1944 and could not be traced. The remaining three animals and
a healthy bull as control, were injected subcutaneously with 0.5 c.c. of pneumonic lung emulsion
and pleuritic effusion on the 24th November 1944.
Reaction The vaccinated animals showed slight local swelling. It was hard, slightly painful
and localized. It remained almost the same size for about a week and then gradually disappeared.
In one animal the local swelling was slightly bigger than those of the other two and also subsided
a few days later. There was no thermal reaction and the animals appeared normal and healthy
during the observed period of three months.
The reaction in the control bull was typical and similar to those previously observed in the
transmission experiments. The animal appeared dull on the 8th day and the local swelling began
to extend from the seat of inoculation to the region of the left shoulder. There was rise of tempe-
rature up to 105.2ºF. (10th day) and later it was a degree or two more than the normal. At first,
the swelling at the seat of inoculation was hot, painful and oedematous. Then, it increased in size,
progressively extending further and involving the neighbouring tissues. There was no indication
of abscess formation. The swelling extended to more than half way in the region of the neck, down
to the dew-lap and to the sternal region, presenting a contiguous extensive swelling. Appetite
was impaired and the bull was very dull with staring coat. The general condition was poor. During
the early stage it was lame and subsequently it limped on three legs and finally assumed recumbent
position for about three days before it died on the 19th December 1944 (25th day).
Post-mortem lesions at the seat of inoculation were extensive. The cut surface was reddish-
yellow in colour, firm and hard in consistency. There was oedema with pronounced serous infiltra-
tion of the subcutaneous and intramuscular connective tissues. The prescapular lymph gland was
enlarged and oedematous. There was nothing note-worthy in the lungs.
DISCUSSION
Cattle vaccinated on the 12th January 1943 were tested for immunity on the 24th November
1944 with a fresh and virulent strain obtained from a seat of outbreak of bovine contagious pleuro-
pneumonia. The control bull reacted typically and died, manifesting specific lesions. Out of the
three vaccinated cattle, one showed slight reaction or rather more local reaction than the other two,
and all the three survived. Although the number of animals tested is small for drawing definite
conclusions, yet there seems to be evidence that the duration of immunity is nearabout 22 months.
The fresh material used for the immunity test, was also sent to the Imperial Veterinary Research
Institute, Izatnagar, from which the virus was obtained.
In this connection, it is interesting to refer to the work in Australia. A different technique
has been developed and is now employed for experimentally reproducing the typical pulmonary
disease in cattle as well as for testing the value of immunization procedures (private communication
dated the 4th December 1944 from Dr A. W. Turner). Campbell [1938] has reported that the
disease produced experimentally in cattle, by the atomization technique, is in all respects identical
with the naturally occurring disease. The exposure of animals to finely atomized culture is also
used as a method of testing cattle for resistance produced following vaccination. The results of
experimental tests by this method are reported to indicate that immunity is maintained for more
than twelve months. Further, he suggested that animals vaccinated with a strain of the organism,
possessing a relatively high degree of virulence, maintain a high and lasting immunity. In case of
comparatively avirulent strain, the immunity is said to wane after two months. In regard to single
and double vaccinated cattle, there appears to be no significant difference in the immunity set up
when exposed at an interval of twelve months after vaccination.
SUMMARY
Details are given of the experimental vaccination carried out in two localities—Gauhati and
Kukuria—in Assam, against bovine contagious pleuropneumonia.
Observations on the reaction following the inoculation of pleuropneumonia vaccine (culture-
virus-vaccine) by tail-tip or Willem's method, are recorded.