Dracunculus insignis and related species

Dracunculus insignis, originally described in 1858, was first recognized in North America in 1932 in carnivorous mammals. The nematode was first reported as D. medinensis (also known as Guinea Worm, a closely related species which infects humans in Africa and nearby areas) but was later found to be a distinct species. It was suggested that other Dracunculus nematoes previously reported in North America were also D. insignis (Ewing, 1966). Though the species is found in carnivorous mammals including raccoons, dogs, and skunks, the study of this species could lead to a better understanding of D. medinensis infections in humans (dracunculiasis).
Dracunculus larvae are eaten by copepods in bodies of water. When the infected copepods are ingested by larger mammals, the larvae will mature and migrate to muscle tissue causing severe pain and swelling which can be problematic to people in poorer areas who must do strenuous work to survive (Fargo, 2003). Though D. insignis does not infect humans, drugs may be tested on it in infected mammals which may lead to better drugs to combat D. medinensis. Treatment of drinking water to kill larvae-containing copepods, though effective, may not always be feasible in certain areas of the world. Boiling of water or chlorine tablets may be too time consuming or expensive for local people to bother doing. Treatment of the drinking water source may be done, but that will not be permanent as new copepods may be introduced to the water. As soon as a person infected with a fertile female nematode comes in contact with the water, the worm may release larvae into the water, once again infecting the copepods present (Fargo, 2003). Deep wells would create clean sources of water, but would be too expensive for all communities to build.
There is currently no specific drug of choice for treatment of dracunculiasis in humans. The most common way to remove worms is by manually extracting ones which have created a pustule near the surface of the skin by wrapping the nematode around a stick to slowly pull them out. If a cheap, easily accessible drug could be found to kill the worm, then control of the disease may be more feasible. As D. medinensis is not known to have a reservoir host (Bimi et.al. 2005), D. insignis would be the easiest way to study new drugs without having to resort to human subjects.

Works cited:
Ewing, S. A., Hibbs C. M. 1966. Dracunculus insignis (Leidy, 1858) in Dogs and Wild Carnivores in the Great Plains. American Midland Naturalist. 515-519

L. Bimi, A. R. Freeman, M. L. Eberhard, E. Ruiz-Tiben and

N. J. Pieniazek. 2005. Differentiating Dracunculus medinensis from D. insignis,

by the sequence analysis of the 18S rRNA gene.
Annals of Tropical Medicine & Parasitology, Vol. 99, No. 5. 511-517.

Fargo, D. 2003. "Dracunculus insignis" (On-line), Animal Diversity Web. Accessed September 20, 2012 at http://animaldiversity.ummz.umich.edu/accounts/Dracunculus_insignis/

Fargo, D. 2003. "Dracunculus insignis" (On-line), Animal Diversity Web. Accessed September 20, 2012 at http://animaldiversity.ummz.umich.edu/accounts/Dracunculus_insignis/

Fargo, D. 2003. "Dracunculus insignis" (On-line), Animal Diversity Web. Accessed September 20, 2012 at http://animaldiversity.ummz.umich.edu/accounts/Dracunculus_insignis/

Fargo, D. 2003. "Dracunculus insignis" (On-line), Animal Diversity Web. Accessed September 20, 2012 at http://animaldiversity.ummz.umich.edu/accounts/Dracunculus_insignis/