Dracunculosis, also known as dracontiasis or guinea worm disease, is caused by Dracunculus medinensis.
Dracunculus medinensis females are generally about 70 - 80cm long, rarely exceeding 100cm. After humans drink the contaminated water, the larvae enter the human body and complete their life cycle. Although certain animals can also be infected, humans are their main hosts.
Human stomach acid can help the larvae release from the swallowed copepods, and the larvae reach the loose connective tissue through the stomach wall. The larvae develop into adults in 10 - 14 months, and there are not histologic reactions. After mating, the males die, and the pregnant females migrate in the subcutaneous tissue, often entering the end of the lower extremities, leading to localized vesicles containing inflammatory cells and eosinophils. Finally, the vesicles rupture. After the skin lesions are in contact with water, the larvae are released into the water from the uterus. Ruptured worms in the tissues can cause strong inflammatory responses, leading to abscess formation.
Signs and Symptoms
Dracunculiasis is usually asymptomatic in the first year. Typical symptoms occur when worms penetrate the skin. Local symptoms include severe pruritus and burning pain at the rash. There are allergic reactions such as urticaria, erythema, dyspnea, vomiting, and pruritus. If the worm body is ruptured, severe inflammation and pain can occur. Once the worms are eliminated, the symptoms subside and the ulcers heal spontaneously. Secondary bacterial infections may occur in 50% of patients.
Arthritis, fibrous ankyloses, tendon contractures, and arthralgia may occur in the chronic stage.
If there are typical clinical manifestations and larvae found in feces or skin lesions, the disease can be diagnosed. Calcified worms may be found in the X-ray examination.
The common treatment is to slowly and carefully roll out the worm with a stick over days to weeks.