Dracunculcus medinensis

Velschius, 1674; Rudolphi, 1819; Forbes, 1838; Bastian, 1863;

Dracunculcus medinensis is the causative agent of daracunculosis, which has been known for centuries. A few decades ago, the number of infected people was around 3.5 million. Appropriate preventive measures and therapies have reduced the number of infected people to a few hundred cases. The infection is practically only rampant in South Sudan.

The male reaches a length of 3-4 cm, the female up to 1 m. The host of the larvae is the copepod Cyclops.

The transmission of the larvae of the Medina worm occurs via drinking water that has not been boiled. They enter the human organism by swallowing the copepods, which are about 4mm in size, when drinking water. Spread of the larvae in the stomach of the human, penetration of the stomach wall by the females (males die), settlement in the subcutis of the lower limb and maturation into adult forms. The mature worm reaches a length of up to 100 cm in the tissue. 10-14 months after infection, the pregnant female breaks the skin on contact with water and expels her larvae, rupturing the end of the worm. Local inflammation and blistering occurs at this site, and later an ulcer forms. The process is repeated on renewed contact with water until all larvae have been shed. The worm then dies and can be pulled out of the skin. In > 90% mainly feet and lower legs are affected. Mostly infestation by only 1 worm, rarely 2; maximum up to 50. Unusual localisations are scrotum or eye.

Incubation period 8-12 months. Allergic phenomena with fever, urticaria, nausea, diarrhea, dyspnea, eosinophilia, arthritides, sterile abscesses.

Skin lesions: The initial temperature stimulus that attracts the worm results in a 2-3 cm pruritic blister. After rupture of the blister cover, development of shallow ulceration and edema of the surrounding area. The real danger is bacterial superinfection. Also risk of infection with Clostridium tetani. Chronic suppuration, cyst formation and calcifications.

Contrast imaging to localize the worm, followed by surgical removal of the worm via multiple incisions. Local application of 5-10% tiabendazole ointment (e.g. tiabendazole 10%-betamethasone 0.1% cream (O/W) facilitates removal.

In some tropical areas, the worm, which can be > 1 m long, is slowly coiled up with a matchstick from the skin surface over several days to 2 weeks. If this is done too quickly, there is a risk of rupture and the remaining worm can no longer be grasped from the outside. If a remnant remains, it must be surgically removed. This procedure often leads to secondary infections that require systemic antibiotics according to an antibiogram.

Boil or filter the drinking water with close-meshed filters.

Facilitating the removal of the worm is the oral administration of metronidazole 2 times/day 5 mg/kg bw for 10-20 days or 2 times/day 25 mg/kg bw tiabendazole (Mintezol) for 3 days. Think of tetanus vaccination!

Diagnosis and therapy should be reserved for experienced tropical physicians.

1. Cairncross S et al (2002) Dracunculiasis (Guinea worm disease) and the eradication initiative. Clin Microbiol Rev 15: 223-246
2. Centers for Disease Control and Prevention (CDC) (2003) Progress toward global eradication of dracunculiasis, January-June 2003. MMWR Morb Mortal Wkly Rep 52: 881-883.
3. Forbes D (1838) Extracts from the half yearly reports of the diseases prevailing at Dharwar in the 1st Grenadier Regiment, N.I. for the year 1836. Trans Med Phys Soc Bombay 1: 215-225.

4. Rawla P et al (202q) Dracunculiasis. 2020 Jun 2. In: StatPearls. Treasure Island (FL): StatPearls Publishing PMID: 30855819.

5. Rudolphi CA (1819) Entozoorum Synopsis cui accedunt mantissima duplex et indices locupletissima. Sumptibus Augusti Rücker, Berlin

6. Velschius GH (1674) Exercitationes de vena medinensis et de vermiculis capillaribus infantium. Auguste Vindel, Augsburg