Nematodes (Strongyle)

Strongyles, or alternatively, strongyls, are nematode worms of the family Strongylidae, order Strongylida. They are often parasitic in the gastrointestinal tract of mammals, especially grazers such as sheep, cattle and horses.

The eggs of many roundworm species look alike. For this reason WEC tests usually report on the number of ‘strongyle’ type eggs per gram (epg) of faeces present in the sample. Strongyle type eggs include:

small brown stomach worm (Ostertagia ostertagi),
barber’s pole worm (Haemonchus placei),
stomach hair worm (Trichostrongylus axei),
small intestinal worm (Cooperia species),
hookworm (Bunostomum phlebotomum), and
large-mouthed bowel worm (Chabertia ovina).

The type of worm cannot be determined from the egg stage, but can be identified when they hatch into larvae (click here to see a roundworm life cycle), through a process called ‘larval culture and differentiation’.

This laboratory technique mimics conditions suitable for eggs to hatch as they would on pasture. If the WEC is at or above a target number, faeces should be cultured to hatch the eggs and the resultant larvae are identified and counted.