Global eradication of Dracunculiasis

Life cycle of Dracunculus medinensis, via the CDC

While sitting at home waiting for Hurricane Sandy to come ashore, I located this alert from the Centers for Disease Control and Prevention, detailing the current progress on the elimination of dracunculiasis. Public health measures have globally eliminated just two diseases, smallpox and rinderpest, and only the former is a disease of humans. Several other diseases though are on the horizon, and I presented an update on progress with the elimination of polio a few months ago. Most students of health probably have not heard of dracunculiasis, or guinea worm infection, as it is a disease which is endemic in Africa. It is caused by the nematode Dracunculus medinensis, and although it is not a fatal disease, it can cause crippling secondary infections.

Infection is acquired by drinking stagnant water contaminated with the larvae, and the larvae penetrate the host’s stomach and intestinal walls to reproduce in the body in tissue. Male and female worms mate, and the female worm continues to grow while the male dies. The mature female then migrates to the surface of the skin, and creates an abscess typically on the legs or feet. This creates a burning sensation in the victim, which can be soothed by immersing the skin in water. Larvae are then released back into the water to complete the cycle of infection. The female can remain in under the skin, and actually is quite large (70 to 120 cm in length). The parasite can be removed, and this is generally accomplished by grabbing the end of the worm when it extends from the skin, and tying it to a stick.

Guinea worm (Dracunculus)

Guinea worm (Dracunculus) (Photo credit: Wikipedia)

The worm is gradually wound up on the stick, pulling it out from under the skin of the patient. Historians of medicine have hypothesized that the Rod of Asclepius, a symbol used in the health care field, may actually represent this pulling out of a guinea worm from a patient.

The CDC reports the current status in the elimination of this tropical disease. Beginning in 1986, the World Health Assembly targeted to eliminate the disease by 1995, however that goal was not achieved. As of June 2012, dracunculiasis remained endemic in 4 countries (Chad, Ethiopia, Mali, and South Sudan) with 395 cases reported in the first six months of 2012. This number represents a 51% drop from a similar time period in 2011, however some areas in the endemic region (particularly in Mali) are increasing in numbers.

Public health officials are using several approaches in the eradication effort, primarily designed at educational measures and providing potable drinking water:

  • informing residents in endemic regions about the parasite, and to prevent the reintroduction of the larvae into drinking water in documented cases of infection
  • filtering potentially contaminated water to make it potable
  • treating potentially contaminated water with larvacides
  • providing safe drinking water by drilling new wells
  • containment of infection by providing first aid and extraction of worms in infected patients

The eradication effort has progressed somewhat more slowly than the classic story of smallpox, and in some part this due to guinea worm disease being perceived as a “third world” disease, whereas smallpox posed a global threat. Eradication has been hampered as a result by lack of funding. The CDC reports that $72 million dollars have been pledged by the Bill and Melinda Gates Foundation, the governments of the United Kingdom and the United Arab Emirates, and the Children’s Investment Fund Foundation. The CDC feels that this final infusion of funding will enable sufficient manpower to be deployed to completely contain transmission during the upcoming calendar year.

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About ycpmicro

My name is David Singleton, and I am an Associate Professor of Microbiology at York College of Pennsylvania. My main course is BIO230, a course taken by allied-health students at YCP. Views on this site are my own.

Posted on October 31, 2012, in Microbes in the News, Yikes! and tagged , , , . Bookmark the permalink. Comments Off on Global eradication of Dracunculiasis.

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