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Other Names: Proventricular Tetrameriasis, Tetrameriosis
Tetrameriasis is a parasitic infection of poultry caused by Tetrameres spp (T. americana or T. fissispina) roundworms. Tetrameres spp are small parasitic roundworms which invade the proventriculus of chickens, turkeys, pigeons, guinea fowls, ducks, pheasants, and quails. There are two species which infect poultry: T. americana and T. fissispina.
Adult female Tetrameres spp worms embed themselves into the glands or lining of the proventriculus, which induces nodules that can grow so large that they compress the glands and can cause them to atrophy. The mucosa of the proventriculus becomes irritated and inflamed from Tetrameres spp continuously feeding on blood. This can result in the accumulation of undigested food in the proventriculus, which can flow back to the esophagus and the crop that become obliterated.
Tetrameres spp have an indirect life cycle. Birds become infected through ingestion of an intermediate host, which are grasshoppers, cockroaches, earthworms, and water fleas. Adult female Tetrameres worms lay embryonated eggs in the host's gut that are passed in their droppings. Intermediate hosts ingest the eggs from the environment, which release the larvae a few hours later. These larvae complete development to infective L3 larvae in about 7 weeks and become encysted in the body of the intermediate host. The prepatent period (time between infection and first eggs shed) of Tetrameres worms is 7-8 weeks, depending on worm species and host.
Tetrameriasis is diagnosed based on detection of Tetrameres eggs in the feces via a fecal test.
Anthelmintics effective against Tetrameres worms include benzimidazoles (albendazole, fenbendazole, flubendazole, mebendazole, oxfendazole), levamisole, ivermectin, and piperazine.
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