Thelazia lacrymalis



Thelazia lacrymalis
Class Nematoda
Super-family Spiruroidea
Also known as: Equine eye worm

Hosts

Intermediate hosts: Muscid flies.

Definitive hosts: Horses.

Identification

T. lacrymalis is a nematode of the superfamily Spiruroidea. The adults are small, at only 1-2cm in length, and are a pale yellow colour.

Life Cycle

The female worms are viviparous. L1 is passed by the female worm, and is ingested by the fly, acting as the intermediate host. The L1 develop into L2, then into L3 inside the ovarian follicles of the fly. The fly infects the definitive host, whilst feeding.

The prepatent period of T. lacrymalis is 3-6 weeks.