Dracunculiasis

Dracunculiasis, also called guinea worm disease, is an infection by the guinea worm, affecting the subcutaneous and deeper tissues.

A person becomes infected when he/she drinks water that contains water fleas infected with guinea worm larvae.

Cause

Dracunculus medinensis, transmitted to man by drinking water containing water flea or small crustacean infected with larvae of the guinea worm. 

Incubation period

About 2-3 weeks, i.e. from the vesicle rupturing until when larvae has been completely evacuated from the uterus of the gravid worm.

Signs and symptoms

• Adult worm may be felt beneath the skin
• Local redness, tenderness and blister (usually on the foot) at the point where the worms comes out of the skin to discharge larvae into the water
• There may be fever, nausea, vomiting, diarrhea and dyspnoea
• Generalized urticaria and esinophilia before vesicle formation.
• There may be difficulty in walking or work.

Diagnosis

• Dracunculiasis is diagnosed by seeing the worms emerging from the lesions on the legs of infected individuals
• Microscopic examinations of the larvae.

Life cycle of Dracunculus medinensis

• Guinea worm disease is caused by drinking water contaminated by water fleas (microscopic arthropods known as copepods(cyclopoids)) that host the Dracunculus medinensis larvae.
• After ingestion, the copepods die and are digested, thus releasing the larvae, which then penetrate the host’s stomach or intestinal wall, and then enter into the abdominal cavity and retroperitoneal space. After maturation, which takes approximately three months, mating takes place; the male worm dies after mating and is absorbed.
• Approximately one year after mating, the fertilized females migrate in the subcutaneous tissues adjacent to long bones or joints of the extremities.
• They then move towards the surface, resulting in blisters on the skin, generally on the distal lower extremity (foot).
• Within 72 hours, the blister ruptures, exposing one end of the emergent worm.
• The blister causes a very painful burning sensation as the worm emerges, and the sufferer will often immerse the affected limb in water to relieve the burning sensation.
• When a blister or open sore is submerged in water, the adult female releases hundreds of thousands of guinea worm larvae, thereby contaminating the water.
• Infected copepods can live in the water for up to 4 months.

Diagnosis

• Dracunculiasis is diagnosed by seeing the worms emerging from the lesions on the legs of infected individuals
• Microscopic examinations of the larvae.
• Active larvae can be obtained by immersing protruding female in a container with water
• Radiological test reveals dead calcified worms.

Treatment

• The first step is to do a controlled submersion of the affected area in a bucket of water. This causes the worm to discharge many of its larva, making it less infectious. Submersion results in relief of the burning sensation and makes subsequent extraction of the worm easier.
• Slow extraction of the worm. Avoid breaking the worm.
• Clean and dress the ulcer to prevent secondary bacterial infection such as tetanus.
• Give tetanus vaccination.
• Analgesics can be used to help reduce swelling and pain.
• Antibiotic ointments can help prevent secondary infections at the wound site.
• Use of metronidazole or thiabendazole may make extraction easier, but also may lead to migration to other parts of the body.

Prevention

1. Prevent people from drinking contaminated water containing the Cyclops copepod (water flea.

• • Drink water drawn only from sources free from contamination, such as a borehole or wells.
  • Filter all drinking water, using a fine-mesh cloth filter like nylonor sand filters, to remove the guinea worm-containing crustaceans.
  • Boil the water
  • Treat water sources with larvicides to kill the water fleas.

2. Prevent people with emerging Guinea worms from entering water sources used for drinking.

• • Community-level case detection and containment is key. For this, staff must go door to door looking for cases, and the population must be willing to help and not hide their cases.
  • Immerse emerging worms in buckets of water to reduce the number of larvae in those worms, and then discard that water on dry ground.
  • Discourage all members of the community from setting foot in the drinking water source

Complications

• Arthritis
• Crippling
• ulceration
• Tetanus infection
• Abscess formation
• Cellulitis if worm breaks