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RESEARCH PRODUCT

Guinea Worm Infection in Dogs: A Case of Reverse Zoonosis that Impedes Dracunculus medinensis Eradication

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description

Dracunculus medinensis or Guinea worm was largely considered an exclusive human parasite. The adult female D. medinensis (up to 100 cm long and 1.5–2.0 mm thick) inhabits and moves in the connective tissue, including the skin. Large females protrude from the skin causing unusual and unambiguous signs. Hosts become infected by drinking water containing the crustacean intermediate hosts (cyclopoid copepods known as water fleas) infected with Guinea worm L3 larvae. After years of a successful eradication campaign (focused mainly on preventing humans from drinking unfiltered or untreated water), Guinea worm transmission has been eliminated from most, but not all, countries. An unforeseeable high rate of dog dracunculiasis, mainly in Chad, has been detected as a result of the surveillance program started in 2012. This reverse zoonosis is preventing dracunculiasis from becoming the first infectious disease to be eradicated without a vaccine or specific medical treatment and the second human pathogen eradicated after smallpox. The alternative food-borne route of transmission, in which frogs and fish are involved, suggested by scientists of the Guinea Worm Eradication Program in an attempt to explain dracunculiasis transmission route in dogs, is also discussed.