Heligmosomoides polygyrus
| Heligmosomoides polygyrus | |
|---|---|
 | |
| Female H. polygyrus from the digestive tractus of a woodmouse | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Nematoda |
| Class: | Chromadorea |
| Order: | Rhabditida |
| Family: | Heligmosomidae |
| Genus: | Heligmosomoides |
| Species: | H. polygyrus |
| Binomial name | |
| Heligmosomoides polygyrus | |
Heligmosomoides polygyrus (formerly known as Nematospiroides dubius[1]) is a common parasitic nematode found in the duodenum and small intestine of woodmice and other rodents. It is sometimes referred to as Heligmosomoides bakeri.[2]
They are 5–20 mm in length and bright red due to the pigmentation of their tissues. They are usually heavily coiled, with the female having 12–15 coils and the male 8–12. The male can be distinguished from the female by a prominent copulatory bursa and two long, thin spicules at the posterior end.
These worms often form cysts in the wall of the intestine. These cysts often become infected with bacteria, but it is not yet known if these are harmful to the host.
This organism is often used to model human helminth infection in laboratory mice.
Life cycle
Heligmosomoides polygyrus has a direct life cycle. its life cycle began with the eggs that get out with the faeces of suitable host into the environment. After two days they hatch as larvae which size is about 300 μm in length. The larvae moult 3 days later but it retains the shed cuticle layer for protection. It is at this point they become infective. The larvae shed its outer protective sheath layer after they were eaten by the host. The larvae then try to penetrate the submucosa layer of the duodenum where they undergo two further moults.
About seven days later the male and female adult worms emerge into the lumen of the duodenum. They attach to the epithelial layer of the duodenum where they feed on the contents of the gut. When adult worms mate, their eggs are shed in the faeces. The complete life cycle needs a minimum of 15 days, and the female worms will live inside their host for 8 months.
References
- ↑ Wabo Poné, J.; Fossi Tankoua, O.; Yondo, J.; Komtangi, M. C.; Mbida, M.; Bilong Bilong, C. F. (2011). "The in Vitro Effects of Aqueous and Ethanolic Extracts of the Leaves of Ageratum conyzoides (Asteraceae) on Three Life Cycle Stages of the Parasitic Nematode Heligmosomoides bakeri (Nematoda: Heligmosomatidae)". Veterinary Medicine International 2011: 1. doi:10.4061/2011/140293.
- ↑ Behnke, J.M.; Menge, D.M.; Noyes, H. (2009). "Heligmosomoides bakeri: a model for exploring the biology and genetics of resistance to chronic gastrointestinal nematode infections". Parasitology 136 (12): 1565–1580. doi:10.1017/S0031182009006003.