Guinea Worm Infection Quiz

Guinea Worm (Dracunculus medinensis)

• Distribution: Found in areas where communities use shallow ponds or open wells for drinking water
• Adult Morphology: White, smooth surface; female is very long (up to one meter), male dies after fertilizing female
• Habitat: Subcutaneous tissue of lower limbs
• Larva: Large (500-700mm), rounded anterior end, pointed tail. Can be seen coiled or uncoiled in wet preparations.
• Intermediate Host: Cyclops, live in water. Infection occurs when humans drink water containing these infected copepods.
• Life Cycle: Larvae penetrate the host's stomach and intestinal wall, mature, and reproduce. Fertilized female worm emerges from skin after one year. L1 larvae are released into water from the emerging female.
• Pathology and Symptoms:
  • Inflammatory reaction (blister) at skin site when female emerges.
  • Secondary infections (abscesses, ulceration, necrosis, cellulitis, septicemia) can occur when blisters contact cold water and rupture
  • Other symptoms: urticaria, erythema, vomiting, fever
• Diagnosis:
  • Difficult: larvae often washed away into water
  • Diagnosis is usually made when blister ruptures, exposing the anterior end of the female
  • Can also use a few drops of water on ulcer to encourage larva discharge and examine it microscopically.
• Treatment: Carefully roll the worm around a stick and slowly pull it out of the skin

Trichinella Species

• Species:
  • T. spiralis: Infects domestic pigs, rats, cats, and dogs
  • T. nativa: Infects all carnivores
  • T. nelsoni: Infects carnivores and wild pigs
• Distribution: Africa, Asia, and America
• Adult Morphology:
  • Female: White, very small (4mm long), bluntly rounded posterior end, single ovary opening halfway down the body.
  • Male: Small (1.5mm), curved posterior end, lobular appendages
• Habitat: Small intestine
• Larva: Coiled within lemon-shaped cysts, lie longitudinally along muscle fibres. Calcified larvae appear black.
• Life Cycle:
  • Direct life cycle: Definitive host is pigs; accidental host (dead end) is humans.
  • Infective form: Encysted larvae in muscle
  • Infection: Ingestion of raw or undercooked infected meat containing encysted larvae (L1).
• Pathology and Symptoms: Typically mild; severe cases can cause: fever, chills, facial swelling, joint and muscle aches, rash
• Diagnosis:
  • Muscle biopsy (direct or digestion technique)
  • Intra-dermal tests, Bachmann skin test
  • Stool examination (adult presence in severe diarrhea)
  • Xenodiagnosis
  • Serology (ELISA, Latex agglutination test)

Test your knowledge about Dracunculus medinensis, its distribution, life cycle, and the potential health risks it poses. Explore the specifics of its morphology, habitat, and the role of intermediate hosts in transmission. This quiz is essential for understanding this parasitic infection.