STUDIES ON THE HELMINTH PARASITES OF INDIAN
              POULTRY, PART II. THE OCCURRENCE OF
                            GAPEWORM IN FOWLS

                                                BY

                      HAR DAYAL SRIVASTAVA, D.Sc.

                         Helminthologist (On special duty)

     Imperial Veterinary Research Institute, Mukteswar-Kumaun

                  (Received for publication on 25th May 1938)

THE terms gapeworms, y-worms and forked-worms are applied to a
genus of strongyle nematodes— Syngamus v. Siebold [1836], which occur in
the adult stage in the trachea and bronchi of birds and mammals. In their
immature stage the worms inhabit the lungs and air sacs. As the name sug-
gests the males and females remain permanently joined in copula in the form
of the letter ' y '. The most important and widely studied member of the
genus is S. trachea [Montagu, 1811; Chapin, 1925], which occurs in the trachea
and bronchi of many species of birds of different groups. The parasite is
more or less cosmopolitan. In the Fauna of British India, Nematoda, Vol.
1, 1936, Baylis remarks, " The parasite is very widely distributed through-
out the world, but the only record from the Indian region appears to be from
the fowl at Colombo, Ceylon (v. Linstow)". In 1935 the author had oppor-
tunity to examine about a dozen chicken at Bareilly and recovered four speci-
mens of gapeworms from the trachea of two of them. The worms on care-
ful examination proved to be specimens of Syngamus trachea—a worm which
has not been previously recorded from this country. One of the birds was
found to be infested with Catatropis indicus Srivastava [1935]. In the
mature state S. trachea lives in copula attached to the mucous membrane of
the upper part of the respiratory tract. The eggs are laid by the gravid female
while still in copula and pass out under the margin of the bursa of the male
into the lumen of the trachea and bronchi. In their appearance the eggs
differ from those of other strongyle worms in the presence of a thickened oper-
culum at either end. They are in the 16-celled stage when laid. From the
trachea they are coughed up into the mouth and swallowed and are eventually
passed out with the droppings. Under suitable conditions of temperature
and moisture the eggs usually hatch in seven to ten days. The larva under-
goes a moult inside the egg shell. The second stage larva which retains the
cuticle of the first stage is infective and one ecdysis is skipped over in the
development of this parasite. It is, however, not necessary for the larva to

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