18
Anthrax Spore Vaccine in Madras
[VOL. XVIII, PART 1,
TABLE I
Anthrax vaccinations in Madras 1939 to 1946
Apart from outbreaks
.
.
.
.
.
During outbreaks . . .
TOTAL
Bovines
61(1)
555(8)
616
Buffaloes
..
108(3)
10S
Sheep and
goats
16,793(31)
5,366(9)
22,159
Elephants
120
..
120
Totals
16,974
6,029
23,003
Figures in brackets indicate the number of places, where vaccination was done.
In cattle and buffaloes the reactions were negligible and consisted in a small proportion of cases
of slight local swelling, slight fever and dullness. All these symptoms were transient. In elephants,
only slight local swelling was seen. In sheep and goats, as noted by others e.g. Chadda [1939]
symptoms due to the local irritant effect of the strong glycerol diluent were seen. Shortly after the
injection, the animals started running round, jumping and bleating. Some lay down and rubbed their
heads on the ground. Such symptoms caused alarm to the ryots but the signs of acute local irrita-
tion could be easily avoided by diluting the vaccine with two parts of normal saline solution prior
to injection. With the first batch of vaccine from Mukteswar the reaction was very severe and
11.5 per cent of the injected animals (2,600 sheep and 88 goats) died, and some pregnant ewes aborted.
With the milder batches subsequently supplied the reactions consisted only of slight local swelling
and fever, though they were rather more severe in goats, a negligible percentage (below 1.0 per cent)
died.
DURATION OF IMMUNITY
Mitchell [1930 ] in Burma states that from his experience of the immunization of animals against
anthrax, the immunity lasts for about 12 to 16 months. It was found that sheep and goats left
under natural conditions are unable to withstand three months later an inoculation of 1000 MLD of
virulent anthrax culture. In this connection, 29 sheep and 25 goats, with six sheep to six goats as
controls, were tested. That there is some residual immunity however is shown by the fact that
after the test dose, the course of the disease in vaccinated animals is of two or three days, whereas
in unvaccinated ones death occurs earlier. Also, after experimental inoculation, the mortality ratio
as between vaccinated and non-vaccinated is 1:7.3, the numbers used being seven of the former
and 51 of the latter. Since in practice sheep and goats do not contract anthrax within eight months
after vaccination it would seem that they have a serviceable immunity at least for this period. In
some of the enzootic areas annual vaccination of sheep and goats has completely stopped the disease.
The vaccine indeed has become popular in the province. Ryots now understand the value of vaccina-
tion in minimising the losses from anthrax, whereas formerly they were often unwilling to permit
vaccination since deaths from anthrax are usually few, at least at the beginning of outbreaks. Finally,
a test with 1000 MLD of virulent culture applied by Mr Rajagopalan in Madras to an elephant 24
days after its second vaccination produced no reaction.
SUMMARY
Results obtained in Madras from the use of anthrax spore vaccine for cattle, buffaloes, sheep,
goats and elephants are briefly described. Over twenty-two thousand sheep and goats and 120
elephants have been vaccinated during this work. The first vaccines tried were too virulent for