H. D.
SRIVASTAVA
217
serious poultry disease in the United States of America was caused by a species
of the genus Prosthogonimus. The species has since been described as P.
macrorchis by Macy [1934], who has worked out the complete life-history
of the parasite. He has extended the work of the previous American workers
and has shown that the infestation is widely prevalent in the United States.
Taylor [1931] pointed out that though there was no record of the occurrence
of this disease in Great Britain it was likely to make its appearance sooner or
later as members of the genus Prosthogonimus as well as the dragonfly, L.
quadrimaculata, were known to occur in the country.
The early symptoms of prosthogonimiasis are the laying of soft-shelled
eggs and a marked decrease in the egg production. To determine the effect
of the infestation with P. macrorchis, Macy [1934], carried out experiments
on laying hens. He selected a flock of sixteen white-leghorn hens with known
laying records and to eight of them he fed cysts of the parasite obtained from
naiads, the other eight birds were kept as controls. During a fixed period of
observation he found that the controls laid ten times as many eggs as did the
infested birds. The striking fall in egg production was due entirely to P.
macrorchis. Thus it would appear that the worms when present even in such
small numbers as will not cause death of the bird, can be responsible for enor-
mous economic loss to poultry farmers.
The parasite usually lives in the bursa fabricii of both male and female
birds. In laying birds it enters the oviduct, being probably assisted by the
movements of that organ, and is responsible for causing acute inflammation and
the consequent production of abnormal eggs and discharge of albumen. Owing
to irritation retroperistaltic movements are set up in the oviduct causing broken
yolk, albumen, bacteria and parasite material to enter the peritoneal cavity and
giving rise to acute peritonitis. The disease is frequently fatal in even moderate-
ly heavy infestations. An interesting, though not serious, aspect of the disease
is the occasional occurrence of living parasites and parasite material inside
the shell of otherwise normal eggs. This inclusion is possible because the
parasite lives on the surface of the oviduct which secretes the egg material.
Kolan and Chandler, [1925], noticed the following pathological changes
in diseased birds on post mortem examination; heavy emaciation and
anæmia ; fibrinous peritonitis, with a large amount of a sticky, yellow exudate
containing large masses of egg-yolk and albumen, parasites and its eggs. The
ovary showed a number of diseased, collapsed ovules, containing greyish-yellow,
egg-yolk-like material mixed with fibrin and pus. The oviduct was greatly
distended, its serous coverings showing a more or less pronounced reddish
discolouration. The lumen of the oviduct contained a large amount of albu-
men material forming ovoid clots of about one to two cm. in diameter ;
the mucosa was covered with a sticky exudate consisting mainly of albumen,
blood and fibrin; large number of flukes was also present. Bacteriological
examinations, both microscopical and cultural, were negative. Bittner
[1923], and Macy [1934], found infiltration of large numbers of plasma cells