Dracunculus Medinensis

Aka: Dracunculus Medinensis, Guinea Worm

advertisement

II. Epidemiology

  1. Prevalance was as high as 3.5 Million, in 20 countries within Africa, Middle East and India
  2. Following public health efforts, as of 2023 it is limited to five countries (Chad, Mali, South Sudan, Angola, Ethiopia)
    1. Eradication efforts started in 1986 by WHO, Carter Center and Gates foundation have reduced cases by 99.9%
    2. Efforts included education, quarantine of infected patients from public bathing, and drinking water filters
  3. Historically, D. Medinensis has infected humans for millenia (at least back to ancient Egypt)
    1. Worm removal technique (wrapping around stick) may be the source of Rod of Asclepius (Medical icon)

III. Pathophysiology

  1. Dracunculus Medinensis (Guinea Worm) is a Roundworm, among the blood and tissue Nematodes
  2. Humans are primary hosts, making it a prime target for eradication
    1. However, Guinea Worm has also been found in domestic dogs (esp. Chad), cats, wildcats and baboons
  3. Transmitted via ingestion of Nematode larvae in contaminated fresh water
    1. Larvae are ingested by tiny crustaceans (copepods), where the larvae mature over 14 days from L1 to L3
    2. Fresh water, contaminated by infected copepods, is ingested by mammals
    3. Ingested copepods die within the acidic mammalian Stomach, and release the D. Medinensis larvae into the Intestine
  4. D. Medinensis larvae invade the mammalian intestinal wall
    1. Migrate into the abdominal cavity and retro-peritoneal space
    2. Larvae mature into adult worms
      1. Female adult worm
        1. Among the longest Nematode to infect humans (up to 80-100 cm long)
      2. Male worms
        1. Considerably shorter (up to 4 cm in length)
        2. Males die after mating
  5. Adult D. Medinensis female worms migrate into subcutaneous tissue
    1. Form a skin Blister, typically on the lower extremities at 1 year after infection
    2. Skin Blister ruptures and slowly releases the female worm over days to weeks
      1. Results in a severe local burning pain, as well as fever
      2. Skin site is a risk for secondary infection
    3. When mammalian host enters freshwater, female worm lays larvae into the water
    4. Larvae infect copepods to begin another cycle of infection

IV. Findings

  1. Skin symptoms on adult female worm emergence
    1. Skin Blister that ruptures at female worm emergence site
    2. Local severe burning pain at emergence site
  2. Allergic symptoms on larval release from skin
    1. Nausea or Vomiting
    2. Urticaria
    3. Dyspnea

V. Management

  1. No effective drug treatment
  2. Female worm removal as it emerges from skin
    1. Worm is gradually wrapped around as a stick as it emerges over days to weeks
    2. Skin care is performed to prevent secondary infection

VI. Prevention

  1. See Prevention of Waterborne Illness

VII. Resources

  1. Dracunculus Medinensis (Wikipedia)
    1. https://en.wikipedia.org/wiki/Dracunculus_medinensis

VIII. References

  1. Gladwin, Trattler and Mahan (2014) Clinical Microbiology, Medmaster, Fl, p. 367

Images: Related links to external sites (from Bing)

These images are a random sampling from a Bing search on the term "Dracunculus Medinensis." Click on the image (or right click) to open the source website in a new browser window. Search Bing for all related images

Related Topics in Helminth Infestation

advertisement