V. R. GOPALAKRISHNAN
293
DISCUSSION
It would appear that in India contagious bovine
pleuropneumonia has been in existence only in
the province of Assam. The disease has a great
bearing upon the cattle wealth of the province.
Mortality figures rank almost next to those of
Rinderpest. Since intensive investigation has
been carried out and the causal organism has
been isolated, measures of control by way of
vaccination will soon be undertaken.
It is fortunate that the disease has not shown
evidence of spreading to the neighbouring pro-
vince of Bengal, lying immediately west of Goal-
para district along the course of the Brahamaputra.
In the past, as even at the present, large numbers
of cattle have been imported into Assam from the
neighbouring provinces and States. The ab-
sence of exportation of cattle, appears to be the
reason for the disease not having spread outside.
Finally, it would be of interest to refer to the
primary source of infection in Assam, as indicated
by observations in the field. As already mention-
ed, an attempt was made to trace the source of
infection in all the outbreaks. Sufficient evidence
was forthcoming to show that the disease had
spread from some neighbouring villages where
the disease prevailed earlier, or due to purchase or
movement of cattle from the infected area.
It is significant that the occurrence of the disease
has been observed in villages and khutis on either
bank of the Brahamaputra, in the charlands on the
bed of the river and to a less extent in some
localities situated near its major tributaries.
In fact, the existence of the disease in Assam is
usually confined to the districts lying on either
side of the river, from Lakhimpur in the north,
Sibsagar, Darrang and Kamrup along its course,
to Goalpara on the west. It may be mentioned
that the incidence of the disease has been known
since 1913-14 and perhaps even earlier. It is
remarkable that other parts of the province in the
southern region including the Surma valley have
been free from the infection. This might be due
to the hill ranges lying south of the course of the
river, restricting the movement of cattle. The
occurrence of the disease in the riverain tracts
of Lakhimpur district—the district in the north-
eastern corner of Assam or even of India—sug-
gests the source of infection from the neighbouring
country, probably China. There are indications
that the infection has subsequently spread to
localities down the course of the river due to
movement or transportation of cattle.
SUMMARY AND CONCLUSIONS
Details are given of investigation of bovine
contagious pleuropneumonia in Assam and of the
occurrence of the disease as a specific epizootic
with a tendency to spread in a slow and insidious
manner. Full particulars relating to the source
of infection, nature of outbreak and localities
affected are given.
Symptoms, course, post mortem lesions, means
of control and treatment are described. Infection
is generally confined to cattle. Mortality is high,
viz., 60 to 70 per cent.
Buffaloes contract the infection only in the later
stage of the outbreak and that too rarely. Goats
and sheep appear to be resistant to natural in-
fection.
Successful transmission experiments with fresh
lung exudate have been made in healthy bulls at
Gauhati. Experimental reproduction in goats
was unsuccessful.
The causal organism of the disease—Borre-
lomyces peripneumoniae—has been isolated by the
Imperial Veterinary Research Institute, Mukte-
swar, from material sent from natural cases
occurring in Assam. From field observations and
laboratory findings, there is substantial evidence
that the disease, as it occurs in Assam, is the classi-
cal contagious bovine pleuropneumonia occur-
ring in other parts of the world.
In India, this disease appears to exist only in
Assam.
ACKNOWLEDGEMENTS
I wish to express my gratitude and thanks to
Mr F. Ware, C.I.E., F.R.C.V.S., F.N.I., I.V.S.,
Animal Husbandry Commissioner with the Gov-
ernment of India, for advice and encouragement,
and to Dr F. C. Minett, D.Sc., M.R.C.V.S., Direct-
or, Imperial Veterinary Research Institute, for
valuable suggestions. To Mr J. F. Shirlaw,
M.R.C.V.S., Officer-In-charge, General Disease
Investigation Section, Imperial Veterinary Re-
search Institute, I acknowledge my indebtedness
for arranging the examination of specimens and
for suggestions offered. I wish to place on record
acknowledgement of the assistance and facility
received from Rai Bahadur S. C. Ghose, and from
Mr A. K. Mitra, M.R.C.V.S., Director, Veterinary
Department, Assam.
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