Parasitology

• Disease: Trichuriasis
• Habitat in human: Large intestine – specially caecum and colon
• Diagnosis of infection: Microscopic examination of faeces to detect eggs

Morphological Features

• Colour: Greyish white worm, often with a pink tint on posterior part
• Shape: resemble a whip – thread-like along most of body, with a thicker short portion at posterior end
• Mouth is a simple opening – lacks lips
• Buccal cavity is tiny with a spear-like projection
• Oesophagus: Narrow non-muscular tube; no posterior bulb; occupies ~2/3^rd of body length
• Posterior 1/3^rd of body contains intestine and reproductive organs

Male

• Size: Less than 4.5 mm long – slightly smaller than female
• Posterior end is coiled
• Single copulatory spicule in a retractile sheath covered with spines
• Single testes

Female

• Size: 3 – 5 cm long
• Posterior end is bluntly rounded
• Single ovary