DRACUNCULIASIS ERADICATION

Dracunculiasis, also called guinea worm disease, is the only parasitic disease that may be totally eradicated from the world in the near future. Although widely distributed at the beginning of the 20th century, active foci of the disease are now found only in Africa south of the Sahara and in Yemen.

Prevalence

· Dracunculiasis is now prevalent in 17 countries, of which 16 are in Africa and 10 are in the category of least developed countries (LDCs).

· In 1997 there were less than 80 000 cases reported worldwide, compared to some 1 million cases in 1989 when national surveys started to be implemented.

· In Nigeria, the annual number of new cases was reduced from 653 000 in 1988 to less than 12 000 in 1997. In Ghana, despite an increase in cases between 1996 and 1997, the total number of new cases was reduced from nearly 180 000 in 1989 to less than 8000 now.

· Cameroon has reported only one indigenous case this year. Several imported cases have been notified all originating from a close-by Nigerian focus.

· The list of other endemic countries includes Benin, Burkina Faso, Central African Republic, Chad, Côte d’Ivoire, Ethiopia, Kenya, Mali, Mauritania, Niger, Senegal, Sudan, Togo, Uganda and Yemen, all of which have instituted campaigns to control the disease.

Characteristics

Dracunculiasis is caused by the parasite Dracunculus medinensis, commonly known as the guinea worm, which is the largest of the tissue parasites affecting humans. Once it infects a person, the parasite migrates through the body. The worm eventually emerges (from the feet in 90% of cases), causing an intensely painful oedema, a blister and then an ulcer. Perforation of the skin is accompanied by fever, nausea and vomiting. Infected persons frequently remain sick for several months.

The disease is only contracted by drinking water sources contaminated with the infected intermediate hosts of the parasite, called cyclops. The full-grown worm begins to migrate throughout the infected person’s body within about one year after ingestion. In endemic countries, the disease typically reappears every year during the agricultural season, with farmers in particular being affected. There are no drugs to treat the disease.

WHO Strategy for Eradication

In 1997, the World Health Assembly adopted a resolution reiterating its request that dracunculiasis be eradicated as soon as possible. The eradication strategy adopted by WHO is based on a three-fold approach: interruption of transmission, surveillance and certification. Interruption of transmission and surveillance combine a variety of interventions including:

· integrated community-based surveillance systems;

· intensified case-containment measures;

· provision of safe water including appropriate water supply systems, filtering devices and the chemical treatment of water to eliminate the vector;

· health education;

In addition, the Dracunculiasis Eradication Programme for coordination purposes has established the following:

· monitoring of the dracunculiasis situation through the use of geographical information systems (GIS);

· interagency collaboration;

Dracunculiasis transmission should be halted in all affected countries early next century given political and financial support. Burkina Faso, Nigeria and Sudan are expected to be the last countries where interruption of transmission will to take place. Strengthening of surveillance in endemic and risk villages, intensifying social mobilization, increasing involvement of communities themselves and improving the awareness and active participation of decision-makers in eradication efforts are the stepping stones to successful interruption of transmission.

Global Resources Needed

WHO, UNICEF, Global 2000, bilateral agencies, several NGOs, and the countries themselves contribute to the interruption of transmission, programme monitoring and surveillance processes. Certification of eradication falls directly under the mandate of WHO. The Dracunculiasis Eradication Programme at WHO has estimated at US$ 40 million the financial needs to achieve the ultimate goal of eradication. Today, US$ 12 million are required for 1998-1999 to meet both coordination activities and country programme needs.

For further information concerning global control strategies for tropical diseases, please contact Dr Kazem Behbehani, Director, Division of Control of Tropical Diseases, WHO, Geneva, Tel (41 22) 791 3826; Fax (41 22) 791 4777. For information concerning the eradication of dracunculiasis, please contact Dr Nevio Zagaria or P. Cattand, Dracunculiasis Eradication, WHO, Geneva, Tel (41 22) 791 2534 or 791 3880; Fax (41 22) 791 4777.