Trichuris ovis: Whipworm

General Description: Long nematodes with a long, slender neck end and a much thicker hind end, giving them the appearance of a whip. Males are 50 to 80mm long and have a curled tail. Females are 35 to 70mm long.

Life Cycle: Direct nematode life cycle. Infective larvae develop within eggs in about 3 weeks and are probably second-stage. These infective eggs are very resistant to stresses in the environment and remain viable for years. Sheep become infected when they ingest the eggs. Digestion causes hatching of larvae, and adult worms develop in the cecum. Prepatent period is 1 to 3 months.

Location: Caecum

Geographical Distribution: Worldwide.

Significance: Importance in sheep is unknown. Clinical disease is produced only in heavy infections, but its effects are additive to other worms.

Effect on Host: Heavy parasite loads may cause thickening of the cecal wall. Fluid absorption that normally occurs there is impaired and diarrhoea results.

Diagnostic Information: Barrel-shaped eggs with transparent plugs at both ends appear in faeces.

Control: Infected sheep should be treated with effective anthelmintics. Avoid use of contaminated pastures.

Trichuris – adults		Whipworm egg		SEM – whipworms in tissue