Dracunculus medinensis - Guinea Worm

Guinea Worm
foe medical students

1. Dracunculus medinensis Guinea Worm Medina Worm Dragon Worm

2. classification

3. Morphology One of the largest nematodes known . Adult females have been recorded up to 120 CM long Few males known do not exceed 40 mm.

4. ADULT WORM Length 60-120 CM Thickness 1-2 mm Anterior end is blunt posterior end is tapering and is bent to form a hock Viviparious Gravid female discharge embryos in batches Male is 10-40 mm length 0.4 mm thick Not seen mostly- dies after fertilization Posterior end male is coiled Male Female

5. LARVA 500-750 μ M LENGTH 5-25 μ M DIAMETER BROAD ANTERIOR END It has a slender tapering tail Larva set free only when the affected part is submerged in water

6. Life cycle

7. First-stage larvae are released into water by a mature female worm It remain active in the water up to 1 week until they are ingested by a suitable cyclops The transformation to infectious third stage larvae occurs within 2 weeks

8. Infection of man is effected when swallowing infected cyclops After 3 month the worms mate and the male dies. The female continues to grow and travel down the muscle planes. The female emerges after 10-14 months to release larvae in water and completes the cycle…

9. pathogenesis 1 year – asymptomatic Before blister symptoms Nausea, vomiting, erythema, urticarial rash & pruritis blister – reddish papule with vesicular centre souround induration common site – feet ankle metatarsal Secondary infection at ulcer

10. Lab diagnosis Detection of adult worm : Gravid female worm appears at the surface of skin After death may become calcified can be detected radiological

11. Detection of larva Contact with water – large amount of larva discharges Microscopic examination Serology Antibody seen in serum by elisa & fluorescents antibody test Skin test Antigen is injected intradermal to see wheal reaction Blood test – eosinophilia

12. Treatment Removal of worm By twisting it around Take weeks to months Metronidazole, niridazole , membendazol Surgical removal of worm

13. Prevention Filtering or boiling drinking water Preventing the infected person from water sourse Cyclops are killed by insecticides using tube wells

14. History Known as a parasite of humans since about 1530 B.C. Guinea worm is thought to be the "fiery serpent" referred to in the Bible. The symbol of a Physician is the "Caduceus". The serpents are believed to represent the Guinea worm. Persian physicians removing the D. medinensis parasite from patient during the 9th century- 

15. Thank you