INFECTIVITY BY CONTACT OF RINDERPEST VIRUS, INCLUDING GOAT-
ADAPTED VIRUS, FOR CATTLE AND GOATS*
By C. SEETHARAMAN, B.Sc, B.V.SC, Indian Veterinary Research Institute, Mukteswar-Kumaun
(Received for publication on 3 February 1948)
(With four text figures)
E DWARDS [1927] succeeded in implanting virulent rinderpest bull virus in goats by passing it
through the foetal membranes of pregnant animals. In this way, a goat-adapted rinderpest
virus was elaborated which, while retaining its specific pathogenicity for goats, was of value for protect-
ing cattle and which is in use for this purpose in India up to the present time. This weakened virus,
produces in Indian cattle only a mild thermal reaction but the immunity is serviceable and lasting,
and under experimental conditions at Mukteswar has been proved to endure for some ten years.
After extensive use of this product for nearly twenty years, both in free areas and in the face of out-
breaks, almost no adverse comment has arisen as to its value and safety. On the other hand, im-
ported cattle, water buffaloes, cattle of pure-bred progeny, and native cattle with an admixture
of foreign blood tend to show a more severe thermal reaction and other ill effects. To control such
undesirable reactions it is well known to be sufficient to inject at the same time a small quantity of
rinderpest immune serum, say 10 to 40 c.c. per 100 lb. body weight. This serum-simultaneous method
using goat-virus has also been adopted with satisfactory results, both under laboratory and field
conditions [Bawa, 1940] for protecting sheep and goats against rinderpest. During the past twenty
years the general observation has been made that the use of goat-virus produces centres of infection
neither in native cattle nor in more susceptible cattle. Experiments in the same connection have
been made, both at Mukteswar and in the field, to determine whether cattle undergoing vaccination
with the modified virus are infectious for healthy cattle and goats by contact. As a result, it seems
evident that under what may be called ordinary conditions of contact transmission does not occur.
However, it still remained to be ascertained whether transmission might occur under conditions,
some of them admittedly rather artificial, which would enhance the chances of transfer. The results
of experiments in this light are reported here.
EXPERIMENTAL
The strains of virus used were (i) a virulent bull virus, designated Line 'E' This virus is highly
pathogenic for hill bulls and causes a mortality of 95 per cent. (ii) a goat-adapted virus, designated
Line 'W', which is maintained at this Institute for supplying goat spleen tissue to the field for immu-
nization work. Representative temperature charts of these viruses in bulls and goats are given
in Figs. 1 to 4. The animals used in the experiments were goats and Kumauni hilll bulls. The latter
according to Edwards, are 18 times as susceptible to rinderpest as plains cattle. The goats were
brought from the plains and the goat-modified virus has a specific pathogenicity for these animals.
To represent various degrees of contact that are possible under ordinary field conditions, ex-
periments were made as follows :
(i) In a cattle shed. This was of the double row type, 50 × 20 feet, in which the animals are tied
facing away from one another. At each end there are two doorways, between which runs a central
passage, three feet wide. The house has no separate feeding passages and is divided into stalls, six
feet wide. For ventilation there are skylights in the roof and three windows in each of the long
walls. In this experiment two animals were tied in the one stall, the windows were always closed
and doors opened except at night.
(ii) In a chappar, where still closer contact between healthy and infected was possible.
This was really a small room, 10 feet square, and about large enough to accommodate two hill
*Paper read at the Indian Science Congress 1948,
69
B