Dracunculiasis Guinea Worm Disease

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DracunculiasisGuinea Worm Disease
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Dracunculiasis

• Commonly as the Guinea worm disease
• Causes by the largest of tissue parasites
  affecting humans, the parasitic round worm
  Dracunculus medinensis
• Transmitted to people when they drink water
  containing copepods that are infected with
  Dracunculus medinensis
• Rarely fatal but often incapacitating for
  several months
• Not currently possible to drugs prevent or treat
  with

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Historical

• Thought to be referred to in a book written in
  Egypt 3,500 years ago (the Ebers' Papyrus).
• Probably the "fiery serpent" referred to in the
  Bible.
• Also may be the coiled serpents on the "Caduceus"
  the symbol of a physician.

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Dracunculus medinensis

• Epidemiology
• . In 1986, there were an estimated 3.5 million
  cases of Guinea worm in 20 endemic nations in
  Asia and Africa. The number of cases has been
  reduced by more than 99 to 3,190 in 2009, 3,185
  of them in the four remaining endemic nations of
  Africa Sudan, Ghana, Mali and Ethiopia.

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Map-2002
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The life cycle
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Life Cycle

• Adult females in subcutaneous tissues of the legs
  and arms.
• Blister forms over nematode. Breaks when exposed
  to water.
• Nematode uterus ruptures and discharges first
  stage juveniles into the water (ovoviviparous).
• Juveniles ingested by copepod (intermediate host,
  2 molts within copepod).
• Copepod swallowed by human.
• Juveniles migrate via lymph system.
• Develop to adults in subcutaneous tissues.

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MORPHOLOGY
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Morphology

• Dracunculus medinensis is usually white
• The adult female is among the longest nematodes
• Often measures one meter in length
• No more than 1-2 mm wide (thin like spaghetti)
• The male is generally much smaller and raerly
  recovered from humans because he dies shortly
  afer mating

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Symptoms
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Symptoms/Pathogenicity

• None until blister forms and toxic fluids result
  in -
• a rash accompanied by severe itching
• nausea
• vomiting
• diarrhea
• dizziness.
• Secondary bacterial infections of opening are
  possible.
• There may be later symptoms--fibrosis of the
  skin, muscles, tendons and joints ( may interfere
  with locomotion or use of limbs).

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Symptoms

• On occasion worms migrate to joints , die
  prematurely, calcify
• The calcified worms can trigger arthritis, locked
  joints, or permanent crippling deformities

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Diagnosis

• Made by observing visible characteristics of the
  disease communicating with the infected person
• Possible to discover infection up to six months
  befor emergence
• Enzyme-linked immunoelectrotransfer Blot (EITB)

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Treatment

• There is no cure. The only treatment is to remove
  the worm over many weeks by winding it around a
  small stick and pulling it out a tiny bit at a
  time. Sometimes the worm can be pulled out
  completely within a few days, but the process
  usually takes weeks or months.
• No medication is available to end or prevent
  infection. However, the worm can be surgically
  removed before the wound begins to swell.
  Antihistamines and antibiotics can reduce
  swelling and ease removal of the worm

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Prevention

• To stop the infection of the Guinea worm you must
  keep Guinea worm larvae out of the drinking
  water. Use only water that has been filtered or
  obtained from a safe source.
• Water can be boiled, filtered through tightly
  woven nylon cloth, or treated with a
  larvae-killing chemical. People with an open
  Guinea worm wound should not enter ponds or wells
  used for drinking water.