Review on Major Gastrointestinal Parasites that Affect Chickens

Abstract

Parasitic diseases are among the major constraints of poultry production. The common internal parasitic infections occur in poultry include gastrointestinal helminthes (cestodes, nematodes) and Eimmeria species. Nematodes belong to the phylum Nemathelminthes, class Nematoda; whereas Tapeworms belong to the phylum Platyhelminthes, class Cestoda. Nematodes are the most common and most important helminth species and more than 50 species have been described in poultry; the majority of which cause pathological damage to the host.The life cycle of gastrointestinal nematodes of poultry may be direct or indirect but Cestodes have a typical indirect life cycle with one intermediate host. The life cycle of Eimmeria species starts with the ingestion of mature oocysts; and each infective oocyst is formed by four sporocysts; and in turn by which each sporocyst contains two sporozoites.Diagnosis of gastrointestinal parasites would be done by direct smear and floatation techniques for faecal samples; but to be confident none is comparable with postmortem examination since it may allow investigating the adults together with pathological lesions.Helminth infections are known to cause interference with host metabolism; and Coccidiosis induced by Eimmeria species infection is an important parasitic disease of poultry which generates economic losses due to morbidity, mortality, reduced body weight, and the expenses related to preventive or therapeutic control and/or vaccinations.Some worms require an intermediary host, such as earthworms, snails, insects etc., and consequently preventing contact with these invertebrates is an obvious step in control and prevention.

Keywords: Chickens, Nematodes, Cestodes, Eimmeria Species.