Caption: Poultry roundworm (nematode, Heterakis gallinarum). The stomodeum is the mouth and lip region (buccal cavity) of nematodes. It consists of having three lips each equipped with small piercing projections or papillae. This nematode infects domestic chickens and related birds. Infection occurs when eggs are usually eaten from soil. The second stage juveniles hatch in the gizzard or duodenum and pass down to the ceca. Most complete their development in the lumen, but some penetrate the mucosa, where they remain for 2 to 5 days without further development. Returning to the lumen they mature into adults. Adult roundworms lay eggs inside the infected bird. The eggs develop in to the infective stage and are voided from the host through the feces. They can remain infective for up to 4 years in the soil. Infective eggs, if eaten by an earthworm, may hatch into juveniles and become dormant in the worm's tissues remaining infective to chickens for at least a year. Since the nematodes do not develop further until eaten by a bird, the earthworm is called a paratenic (transport) host.
Magnification*: x400
Type: SEM
Copyright 2003 Dennis Kunkel Microscopy, Inc.
Keywords: 23064C,03.01.03,animal disease,ascarid nematode,ascarid roundworm,bird disease,buccal cavity,cecal nematode,cecal roundworm,cecal worm,Heterakis gallinarum,misc. invertebrates,Nematoda,nematode,parasite,parasitic,paratenic host,poultry nematode,roundworm,stomodeum,helminth,SEM