III.-AN OUTBREAK OF PASTEURELLOSIS IN DUCKS
By S. K. BHADURY, B.Sc., Assistant Disease Investigation Officer (Poultry), Bengal
(Received for publication on 20 January 1947)
T HE disease, though not uncommon, seems to have been little described so far as concerns symp
toms, post-mortem features and other correlated aspects of diagnosis and control. The
present article deals with a subacute type of outbreak in Bengal. Pasteurellosis was first suspected
from microscopical examination of films prepared from the heart blood of affected birds, and diagnosis
was subsequently confirmed by biological test. A significant point was that the causal organisms
could be demonstrated only in birds in which the course of the disease was prolonged. The charac-
teristic liver lesions, viz. greyish necrotic foci, were a regular feature in the protracted cases, and
were absent in the less acute cases, in which also films from heart blood were apparently free from
organisms.
History. About the middle of March, 1946, a firm of contractors in Calcutta sent to my
laboratory two living and one dead duck from their farm. This farm was started about six months
previously and to its stock frequent additions were made from time to time from local markets.
Prior to the investigation the total number of ducks on the farm was 300. For the previous two
months sporadic deaths of one or two ducks were reported, and were ascribed to the overwhelming
number of males to females. Little was done to combat these losses, and no serious attention was
paid to these isolated reports. This state of affairs continued until suddenly the mortality figure
rose to fifteen dead in a single day. The owners, then suspected some contagious disease and segre-
gated the affected birds, but heavy losses continued during the next few days till the matter was
referred to me.
Investigation. The duck farm was spacious and was sheltered by tall shady trees. Adjoining
was a wide, deep, semicircular pond. Some of the ducks were found to be swimming in the tank,
others were resting or moving about with a certain amount of freedom, in a manner that did not
seem to prohibit fully indiscriminate mixing.
At the date of my visit, the number of ducks on the farm had diminished from 300 to 150,
and about 25 sick birds had been segregated, of which four were already dead. The course of the
disease was generally rapid, varying from 16-20 hours, though some took a protracted course and
lingered up to three days. The disease appeared to have become widespread and losses at this stage
were recorded at the rate of about 30 a day. Six birds (three sick and three recently dead) were
brought to the laboratory for further study.
Symptoms. Clinical symptoms were few but were similar and more or less well pronounced
in almost every case. There was lameness of both legs, foul-smelling greenish-yellow diarrhoea, and
discharge from the eyes, which at times was copious and purulent. In some cases, the eyelids of
both eyes were glued together by an adhesive discharge, but on retracting the lids, the eyes seemed
to be normal. As the disease progressed the birds lost strength in their legs and rested on their
hocks, with head sunken in and turned towards the body. There was respiratory difficulty, marked
by a long inspiration and short rapid expirations. Finally, the neck and limbs were stretched and
the bird collapsed, the body sometimes turning turtle. There was inappetance and general lethargy
throughout, but the leg-weakness was usually the first sign marking the beginning of the malady.
Post-mortem. The carcases were generally in fair condition but heavily infested with lice.
On opening the body, the first noticeable feature was an unusual stickiness of the viscera, which were
enmeshed in a gelatinous, brownish-yellow exudate. This exudate was so gummy, that it hamper-
ed the post-mortem operation. The heart, liver, spleen, lungs, and kidneys showed signs of acute
congestion. The intestines were filled with dark-coloured semi-fluid ingesta, and the mucous mem-
brane showed haemorrhagic patches throughout. In two cases the liver was pale and anaemic.
Caecal scrapings of two ducks showed fairly frequent trichomonads; from the coecum of another
case about two dozen trematodes (N. attenuatus) were recovered.
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