Heterakis

An atypical ascarid.
Lives in the caeca.
1.5cm long, relatively slender and has a pointed tail. (Thus, it does not look like an ascarid, but is otherwise typical of the group).
Eggs similar to those of Ascaridia.
Life-cycle is non-migratory.
Earthworms can act as transport hosts.
This worm is not very pathogenic – its main importance is as the vector of Histomonas meleagridis, the protozoan parasite that causes 'blackhead'.
Another species of Heterakis is a serious pathogen of pheasants. This burrows deeply into the caecal mucosa causing nodule formation, leading to weight-loss and death.