R . L. CORNELL AND RATANA OONYWONGSE 5
TESTS ON BUFFALOES
All the buffaloes used for these tests have been those described as Class
H, that is from an area which has been free from rinderpest for five years,
and they can be depended upon to be at least 90 per cent susceptible. When
infected with bovine or buffalo virus they develop very severe reactions
and the mortality is at least 90 per cent. They are accordingly the most
susceptible stock available and in their lack of resistance remind one of the
Longhorn Ankole cattle of Central Africa though the syndrome developed
after infection presents some differences. Temperature reactions may be
erratic and often show little relation to the severity of other symptoms or
to the chance of recovery and many fatal attacks have been observed which
have been quite apyretic. A typical temperature curve is similar to that
seen in cattle. Lachrymation often but not invariably occurs with the forma-
tion of muco pus at the inner canthus ; as, however, our buffaloes when con-
fined often develop a non-specific conjunctivitis this symptom is not very
characteristic. Dullness and suspension of appetite and rumination set in
about the fifth to seventh day following infection and this is followed by
profuse diarrhœa ; blood and mucus appear in the excreta and the condition
passes to severe dysentery with considerable quantities of pure blood being
passed with the watery stools. Death may occur any time after the sixth
day while some fulminating cases have been observed which died four days
after infection with virus. We have been unable to demonstrate coccidia in
the faeces or ejecta of dysenteric buffaloes or in the faeces of normal animals
before their use for tests or experiments, either by direct smears or by flo-
tation methods, and we have no doubt that acute dysentery can occur in the
absence of these parasites, solely due to a pure rinderpest reaction. On
autopsy the most striking lesions are the acute gastro-enteritis and the
hæmorrhagic inflammation of abomasum, caecum and colon, often with
blood extravasation into the lumen of the gut fully explains the dysentery.
The above short description applies to buffaloes infected with buffalo virus
or with goat virus if severe reactions follow the latter. In experiments we have
injected fifteen buffaloes with goat virus using fresh citrated blood or spleen
suspension in saline, with the result that eight animals died, one appeared
to be immune and six recovered. Of these six, four showed severe symptoms
and two moderate symptoms. These results are shown in Table II.
In addition thirteen buffaloes have been injected with goat virus that
has passed one passage through a buffalo or calf. The experiments were
carried out in connection with infection tests and citrated blood was the
vehicle of virus. Of these thirteen buffaloes, seven died and six recovered,
three showing severe symptoms and three moderate symptoms. These
results are shown in Table III. This series also indicates that a single pas-
sage of goat virus through a calf or buffalo does not enhance its virulence.
Of the two series combined (Tables II and III) fifteen animals died out of a
total of twenty-eight, which included one immune animal, and seven of
thirteen recoveries suffered severe reactions. The series of tests have per-
force been spread over a period of months and different samples of virus
employed, but they clearly show that at least a 50 per cent mortality might