Heterakis gallinarum
| Heterakis gallinarum | |
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| SEM image of the head | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Nematoda |
| Class: | Secernentea |
| Subclass: | Rhabditia |
| Order: | Ascaridida |
| Family: | Ascarididae |
| Genus: | Heterakis |
| Species: | H. gallinarum |
| Binomial name | |
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Heterakis gallinarum Schrank, 1788 |
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| Synonyms | |
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Heterakis gallinae |
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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. Transmission of H. meleagridis is through the H. gallinarum egg.H. gallinarum is about 1–2 cm in length with a sharply pointed tail and a preanal sucker. The parasite is a diecious species with marked sexual dimorphism. Males are smaller and shorter, measuring around 9 mm in length, with a unique bent tail. Females are stouter and longer, measuring roughly 13 mm in length, with a straight tail end.
H. gallinarum has a direct lifecycle involving birds such as chickens, turkeys, ducks, geese, grouse, guineafowl, partridges, pheasants, and quails as definitive hosts. Eggs of H. gallinarum are passed in feces by the host. At optimal temperature (22 °C), they become infective in 12–14 days and remain infective for years in soil. Upon ingestion by a host, the embryonated eggs hatch into second-stage juveniles in the gizzard or duodenum, and are passed to the cecum. Their development is completed in the lumen, but some may enter the mucosa and remain for years without further development. The prepatent time is 24–30 days. Earthworms and houseflies are considered paratenic hosts, as they can ingest the egg in feces and a juvenile may hatch in tissues, which stays dormant until eaten by birds.
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Wikipedia