MUKTESAR, FOR THE YEAR ENDING THE 31ST MARCH, 1927
17
several months, both by direct passage, and by alternate passage through
goats and bulls. The goat virus also possesses a high degree of virulence
for sheep It retains its affinity for the small ruminants even though
after the initial implantation it is maintained by direct passage in bovines.
The morbid changes observed in these animals are principally pneu-
monic, and not alimentary as in bovines. Lung changes are constant,
while in animals that succumb rapidly no lesions may be clearly observed
in the alimentary tract. The disease is readily transmitted by contact.
We suspect that some outbreaks of so-called pleuro-pneumonia in sheep
and goats in India are in reality rinderpest.
The blood of artificially infected goats is virulent as early as the second
day after infection, and by the fourth day has reached a high degree of
virulence, when quantities as low as one-hundredth to one-ten thousandth
of a cubic centimetre may convey the disease to susceptible bulls. The
severity of the disease produced by the goat virus seems to be generally
lower than that conveyed by the bovine virus.
Means have therefore been found to overcome the distressing complica-
tion often observed after the serum-simultaneous inoculation caused by
the unwitting introduction of virulent piroplasms with the rinderpest
blood that has to be injected simultaneously with the serum. The piro-
plasms are parasites that are highly specific for their particular hosts,
and so by diverting the rinderpest virus to hosts other than cattle it
becomes completely separated from the bovine piroplasms. The question
of how to obtain a rinderpest virus that is not accompanied with the
parasites of virulent redwater has therefore now been solved. The
goat is a convenient animal for use as a virus producer; the rabbit was
too small for convenient work and too prone to other diseases (rabbit
septicæmia, coccidiosis) when maintained in large numbers. Researches
are in active progress to discover additional means of extending the
longevity of the virus, and it is hoped that methods will be found within
the next two or three years for distributing rinderpest virus in good
condition to all parts of India so that when field workers employ serum
for the protection of cattle they can with little more trouble and with
little or no risk inject some virus at the same time, and extend the
resultant immunity against rinderpest from one of a few days' duration
to one of some years.
Researches were continued upon methods of economic production of
serum. The results of a large test conducted on ou customary producers
(buffaloes) indicated that there was no advantage in resorting to ' hyper-
immunization ", the serum obtainable by the " immune " method being
equally good. A batch was put on concurrently and repeatedly treated
with small quantities (10 c.c.) of virulent blood mixed with minute
quantities of tapioca grains, to ascertain whether what has been dis-
covered recently by a French authority concerning the properties of
such particles in hindering absorption and hence increasing anti-toxin
production, applied also to rinderpest anti-body production. The
result was not decisive.