Guinea Worm Disease (Dracunculiasis)

Introduction

Dracunculiasis otherwise called Guinea worm disease is an infection by a very long nematode, Dracunculus medinensis.
It is contracted through drinking water
contaminated with water fleas (cyclops) infected with Dracunculus.
Except for remote villages in Rajastan desert of India and Yemen the disease is now only seen in Africa, between the Sahara and Equator.

Pathophysiology

In the stomach, the larvae penetrate into the mesentery, where they mature sexually in 10 weeks.
The female worm burrows to the cutaneous surface to deposit her larvae, causing specific skin manifestations.
When the parasite comes in contact with water, the worm rapidly discharges its larvae, which are ingested by the cyclops.

Symptoms and Clinical features of dracunculiasis

  1. As the worm approaches the surface it may be felt as a cordlike thickening.
  2. It forms an indurated cutaneous papule
  3. Several hours before the head appears at the skin surface there is (at the point of emergence)
  4. Local erythema
  5. Burning sensation
  6. Pruritus:
  7. Tenderness
  8. Soon after, the papule blisters and a painful ulcer develops, usually on the leg
  9. Ulcer may occur on other parts of the body e.g. the genitalia, buttocks, or arms

Differential diagnoses

  • Sickle cell ulcer
  • Stasis ulcer

Complications of dracunculiasis

  • Secondary infection
  • Cellulitis
  • Erysipelas
  • Progressive lymphoedema
  • Oesteomyelitis
  • Arthritis
  • Tetanus

Investigations

Radiograph of the affected area:

  • If osteomyelitis and arthritis (or calcified worms) are suspected

Treatment for Dracunculiasis

Treatment objectives

  1. Resolve local inflammation to permit easier removal of the worm
  2. Extract the worm
  3. Prevent and treat complications

Drug treatment

Metronidazole

  • Adult: 500 mg orally every 8 hours for 7 days
  • Child: 7.5mg/kg orally every 8 hours

Or:

Mebendazole

  • Adult: 400-800 mg orally daily for 6 days
  • Child over 1 year: usually 100 mg orally twice daily for 3 days

Or:

Ivermectin

  • Adult: 200 micrograms/kg orally as a single dose
  • Child: Consult specialist

Treat or prevent complications with antibiotics

Worm extraction

Traditionally:
Extract the worm slowly by winding it about a match stick or twig, removing 3-5 cm daily, with care not to rupture it.
In the event of such an accident, the larvae escape into the tissues and produce fulminating inflammation.
The process appears to be facilitated by
placing the affected part in water several
times a day

Notable adverse drug reactions, caution and contraindications

Metronidazole

  • Avoid high dose regimens in pregnancy
  • Avoid drinking alcohol during treatment and at least 48 hours after

Ivermectin

  • Oedema (face and limbs)
  • Fever, pruritus, lymphadenitis, malaise, hypotension
  • Should not be used in the presence of concurrents loa infection: risk of encephalopatic reactions to dying loaloa microfilariae
  • Should not be used in patients with central nervous system diseases (e.g. meningitis): increased penetration of ivermectin into the CNS
  • Caution in early pregnancy

Prevention of Dracunculiasis

To prevent this disease condition:

  • Provide universal access to safe and portable water
  • In hyperendemic areas, treat the whole population twice yearly with ivermectin