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THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY. [V, I
9. The main contention of Mr. Purvis is that the subject of our article H. B.
288 did not take rinderpest at the initial inoculation, but had perhaps an attack of
Theileriasis. He admits that the pair to this hill bull, inoculated with the same
virus, undoubtedly developed rinderpest but reconciles, what appears to him a
disparity in the reactions on the view that goat virus need not infect 100 per cent.
of susceptible cases.
We have already examined the invalidity of this assumption. If a bull could
resist infection with even 5 c.c. of a viable rinderpest virus, it could not be an acci-
dental occurrence but must have depended upon a natural or previously acquired
resistance, and such resistance could not have collapsed within a period of 74 days.
Mr. Purvis attributes the temperature reaction to Theileriasis. The organism
of which we make mention is T. mutans, which normally exists in nearly cent per
cent. of Indian cattle. In our experience such a temperature curve (the tempera-
ture rising on the 3rd day after inoculation of the virus and coming down by the
7th day), is typical of rinderpest. It could not be due to inoculated Theileria para-
sites, since those of the bovine are not transmissible through the goat, and because
the incubation period of the inoculated Theileriasis is about 13—16 days. If this
were a case of resuscitated Theileriasis, it would be a strange coincidence that the
temperature should rise just on the 3rd day after the virus inoculation. Even
granting this improbability, what could be the exciting cause of resuscitation ex-
cepting rinderpest itself ! In this Institute, where the blood of experimental animals
is regularly examined as a routine measure, nearly cent per cent. cattle are found
to be carriers of T. mutans. It is to be noted that even of the 5 charts of animals
suffering from rinderpest, appended to our article, 4 (i.e., 80 per cent.) showed a
few T. mutans at some stage or other, and yet no one would imagine that they were
suffering from Theileriasis as opposed to rinderpest. The term " a few T. mutans "
is used to indicate that 4 or 5 parasites are detected in the examination of over
hundred fields. When thermal reaction and symptoms such as those seen in hill
bull 288, are due to Theileriasis (Parenthetically it may be observed that T. mutans
never causes these symptoms, but T. annulata or T. dispar is the species which causes
them in India and elsewhere), about 80 per cent. of the corpuscles are invaded and
individual cells may contain as many as 8—12 parasites. The contention that
hill bull 288 did not exhibit the usual clinical symptoms is incorrect since this animal
did manifest all the usual symptoms excepting mouth lesions and this is not a soli-
tary instance of such behaviour following infection with the virus. In the long
experience of this Institute about 20 per cent. of the bulls, used in the alternate
bull-goat virus passage, escape mouth lesions, and yet the virus has been success-
fully passaged from them. It is unfortunate that though the temperature curves
were identical on the 4th day, it fell to the lot of its pair and not to this bull to
be bled for sub-inoculation for further passage. Nevertheless taking together the
various points discussed above, there seems to be not the slightest doubt that it
was at the initial inoculation only that hill bull 288 contracted rinderpest. The
lesions seen at death in this animal are said to be suggestive of a recent infection