5.4 Eradication through community action
Several features of dracunculiasis suggested that a global eradication campaign would be feasible, despite the lack of drugs to kill the worms in the body or a protective vaccine (Box 4). Note the similarity between the first two features and the factors contributing to the global eradication of smallpox – a viral disease with a totally different transmission pattern (see Box 3).
Box 4 Reasons why the global eradication of dracunculiasis is feasible
- Although Dracunculus species are known to infect reptiles and large mammals in areas where guinea worm disease is endemic in humans, there is no evidence that these animals have ever acted as a reservoir for parasites in the human population.
- No other human parasite behaves like D. medinensis, so there is no ambiguity about the diagnosis at the point where the worm erupts from the skin. This makes case finding and case containment relatively straightforward.
- The period in which an infected person poses a risk to others is relatively short (about six weeks while the worm emerges) and the worm larvae are shed seasonally, over a predictable period of 2–3 months, so interventions can be focused intensively at certain times of the year.
- The intermediate host (cyclops) is restricted to still water in shallow pools and step wells, so it cannot easily extend its range (in contrast to an insect vector).
- Transmission to humans is exclusively in drinking water, so if local water sources are protected from contamination by worm larvae, the infection cycle will be broken.