Prevalence and pathology of the nematode Heterakis gallinarum , the trematode Paratanaisia bragai, and the protozoan Histomonas meleagridis in the turkey, Meleagris gallopavo. The prevalence of infection and associated pathology induced by two helminth and one protozoan species infecting Brazilian turkeys are reported. Histological findings in the ceca were represented by the presence of H. The prevalence of the protozoan H. The walls of the ducts presented a discrete heterophilic infiltrate among mononuclear cells.
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These worms do not affect dogs , cats, cattle sheep, goats, horses or swine. The disease caused by Heterakis worms is called heterakiasis or heterakiosis. Predilection site of adult Heterakis worms is the cecum. Occasionally they are found also in the gut.
Adult Heterakis worms are rather small roundworms, not longer than 15 mm, very thin and of a whitish color. Females are longer than males. The worms have a tubular digestive system with two openings, the mouth and the anus. They also have a nervous system but no excretory organs and no circulatory system , i.
The female ovaries are large and the uteri end in an opening called the vulva, which in these worms is located close to the middle of the body. Males have tail flaps alae and a copulatory bursa with two unequally long spicules f or attaching to the female during copulation. Heterakis worms have direct life cycle. Adult female worms in the small intestine pass eggs with the feces about per day per female!
Once in the environment infective L2-larvae develop inside the eggs in 1 to 10 weeks, strongly depending on temperature. These eggs can remain infective in the birds' litter and the environment for one year and longer and may survive slight frost. Birds become infected after eating infective eggs either directly with contaminated food or water, or indirectly when eating earthworms or flies.
Ingested eggs release the larvae in the gut's lumen in a few hours after ingestion. Hatched larvae reach the cecum one day later. Some larvae may penetrate the lining of the cecum, but it seems that most do not and complete development to adult worms in the lumen of the cecum after several molts. The prepatent period time between infection and first eggs shed is 3 to 4 weeks, depending on the worm species and the host.
Heterakis infections are not very pathogenic for poultry. Heavy infections can cause inflammation and thickening of the cecum, appearance of nodules and numerous small bleedings in the cecal wall, especially in turkey.
Egg production in layers can be significantly reduced. However, the major problem is that these worms are vectors of Histomonas meleagridis , a protozoan parasite that affects chicken, turkey, quails, pheasants and many other birds and is the causative agent of the blackhead disease , also called histomoniasis or infectious enterohepatitis. These protozoans remain viable in the eggs. They are particularly harmful and often fatal for turkeys. They can destroy large portions of the gut's wall and liver tissues.
To prevent or at least reduce Heterakis infections it is recommended to keep the birds' bedding as dry as possible and to frequently change it, because development of the worm's eggs needs humidity. Strict hygiene of feeders and drinkers are a must to avoid or reduce their contamination with eggs. Pasture rotation is also recommended.
All these measures are especially important for young birds, particularly for turkeys, which are likely to suffer more from Heterakis infections. They are highly recommended in flocks with a past history of histomoniasis. Numerous classic broad spectrum anthelmintics are effective against Heterakis worms, e. Some compounds with a narrower spectrum are also effective against these worms, e. This means that they have a short residual effect , or no residual effect at all.
As a consequence treated animals are cured from worms but do not remain protected against new infections. To ensure that they remain worm-free the animals have to be dewormed periodically, depending on the local epidemiological, ecological and climatic conditions. So far no vaccine is available against Heterakis worms. To learn more about vaccines against parasites of livestock and pets c lick here. Biological control of Heterakis worms i. You may be interested in an article in this site on medicinal plants against external and internal parasites.
There are a no reports on confirmed resistance of Heterakis worms to anthelmintics. This means that if an anthelmintic fails to achieve the expected efficacy against Heterakis worms it is most likely that either the product was unsuited for the control of these worms , or it was used incorrectly.
Ask your veterinary doctor! If available, follow more specific national or regional recommendations for Heterakis control. Junquera All rights reserved. Control: Introduction Biol. Control of Flies Biol. Control of Ticks Biol. Biology, prevention and control. Chicken heterakiasis.
Heterakis dispar, Heterakis isolonche. Details Written by P. Junquera Last Updated: July 09 Other interesting articles.
Metrics details. Density related effects, both inverse density- and density-dependent, contribute to regulating population dynamics of parasites. We investigated whether density related effects are directly controlling lifetime fecundity of Heterakis gallinarum. Daily total numbers of H.
Heterakis gallinae Heterakis papillosa Heterakis vesicularis Ascaris gallinae Ascaris vesicularis. Heterakis gallinarum is a nematode parasite that lives in the cecum of some galliform birds, particularly in ground feeders such as domestic chickens and turkeys. It causes infection that is mildly pathogenic. However, it often carries a protozoan parasite Histomonas meleagridis which causes of histomoniasis blackhead disease. The parasite is a diecious species with marked sexual dimorphism.