| Heterakis | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Nematoda |
| Class: | Secernentea |
| Subclass: | Rhabditia |
| Order: | Ascaridida |
| Family: | Heterakidae |
| Genus: | Heterakis Schrank, 1790 |
| Diversity | |
| ~10 species | |
Heterakis is the name of a genus of parasitic nematodes. Members of the genus are minute roundworms (pinworms), hardly 1 cm long, infecting different species of gallinaceous birds, including chickens, turkeys, ducks, geese, grouse, guineafowl, partridges, pheasants, and quails. There are approximately 10 species under the genus, but classification is often ambiguous due to their close resemblance, and a number of synonyms have arisen. H. gallinarum Schrank, 1788; H. isolonche von Linstow, 1906; and H. dispar Schrank, 1870, are the best understood species in terms of prevalence, pathogenicity and biology. They inhabit the lumen of the cecum of the host.[1]
The nematodes are whitish in colour, cylindrical and with fine longitudinal striations throughout the body. The body covering is a proteinaceous layer named cuticle. Anterior end is the mouth with distinct lips, and anus opens towards the posterior. They are diecious with marked sexual dimorphism. Males are shorter and smaller, with straight blunt tail; while females are bigger and longer, with curved tail. They all exhibit direct life cycle. They cause nodular typhlitis, diarrhoea, emaciation and death.[2] H. gallinarum is the most well-known species, and is most important as it transmits the protozoan parasite, Histomonas meleagridis in birds.[3][4]