GENERAL CHARACTERISTICS
Dracunculus medinensis, commonly referred to as the guinea worm, is the cause of a subcutaneous infection known as dracunculiasis. The worm has a characteristic, thick cuticle and a large uterus that fills the body cavity and contains rhabditoid larvae.
EPIDEMIOLOGY
The parasite was once known to have a worldwide distribution affecting millions of people. In 2008, the World Health Organization in collaboration with governmental groups and other organizations attempted to eradicate the organism. Efforts have reduced the incidence of infection, confining the remaining endemic area to Africa.
Humans are infected by the ingestion of freshwater from stagnant ponds containing larvae-infected cope pods. The copepods are digested in the stomach, releasing the larvae. The larvae penetrate the small intestine and migrate through the thoracic musculature. Both adult male and female worms mature in approximately 2 to 3 months. The gravid female develops in approximately 10 to 14 months, migrating to the lower extremities. The gravid female produces a blister on the skin, and when the host submerges the affected area in water, the blister erupts and releases larvae into the water.
PATHOGENESIS AND SPECTRUM OF DISEASE
The blisters formed by the gravid female worm cause burning and itching. Systemic symptoms may include fever, nausea, vomiting, diarrhea, headache, urticaria and eosinophilia. Secondary bacterial infections may occur. In addition, dead worms within the host may be absorbed or may calcify, causing secondary inflammatory symptoms.
LABORATORY DIAGNOSIS
Diagnosis is by identification of larvae or adult worms.
THERAPY
Treatment requires removal of the adult worms. The female worms are attached to a stick and slowly retracted from the host by gradual turning of the stick and removal of the worm. Although anthelmintic medications, such as metronidazole or thiabendazole, are not lethal, they are administered to assist with the retraction of the worms. Analgesics and antimicrobials are administered for discomfort and the prevention of secondary infections.
