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Important Helminth Parasites of Poultry
From its normal habitat, the bursa fabrici, the parasite enters the oviduct
in laying birds, being probably assisted by the movements of that organ, and
is responsible for acute inflammation and consequent production of abnormal
eggs and discharge of albumen. Owing to irritation, the oviduct performs
retroperistaltic movements causing broken yolk, albumen, bacteria and
parasite material to enter the peritoneal cavity and giving rise to acute peri-
tonitis. The disease is frequently fatal even in moderately heavy infestations.
An interesting, though not serious, aspect of the disease is the occasional occur-
rence of living parasites and parasite material inside the shell of a perfectly
normal egg. This inclusion is possible because the parasite lives on the sur-
face of the oviduct, which secretes the egg material. The infected bird
becomes extremely emaciated and anaemic. Post mortem examination reveals
the presence of fibrinous peritonitis with a large amount of a sticky, yellow
exudate, containing large masses of egg-yolk and albumen, parasites and
their eggs. The ovary has a number of diseased, collapsed ovules, containing
greyish-yellow, egg-yolk-like material mixed with fibrin and pus. The oviduct
is distended and its lumen contains a large amount of albuminous material
forming clots. The mucosa is covered with a sticky exudate consisting mainly
of albumen, blood and fibrin ; large number of flukes are also present. There
is a sharp decline in egg-production which falls to about 10 per cent of the
normal.
The diagnosis of the disease, especially in the initial stages, is usually
difficult. The earlier symptoms, e.g. laying of soft-shelled eggs and decrease
in egg-production, are likely to be attributed to nutritional irregularities. A
positive diagnosis is possible by the finding of the mature parasite or its eggs
in the faeces or the egg of the suspected bird. In the absence of a constant
passage of bulky material through the oviduct, the eggs are probably dis-
charged only periodically, hence faecal examination is not always reliable.
In the absence of a positive diagnosis, the following symptoms, when taken
collectively, are strongly suggestive of prosthogonimiasis : Inactivity of the
bird, sharp decline in egg-production, laying of soft-shelled eggs, presence or
chalky-white crusts on the feathers around the cloacal region and of hard-
cream coloured chrunks of abortive egg-white and yolk in the oviduct and
abdominal cavity and the distended oviduct filled with fibrinated pus and
the abdominal cavity with pus-exudate, parasites and eggs.
The worms in the oviduct cannot be removed by any method of treat-
ment. In the early stages, while the parasites are still in the intestine, it may
be possible to remove them and thus prevent their entry into the oviduct.
Successful results have been obtained in the treatment of prosthogonimiasis
with carbon tetrachloride given in repeated doses of 1.5 to 1.7 c. c. in liquid
cereal. On account of its toxicity the drug should be used with care.
The occurrence of the parasite in migratory birds, the lack of marked
host specificity and the migratory nature of its second intermediate host
render the problem of prevention extremely difficult. The only possible
method of prevention is by keeping poultry fenced away from permanent
ponds and lakes. As adult dragon-flies are easily caught by poultry on damp