Dracunculus medinensis, also known as guinea worm, is a parasitic nematode transmitted through contaminated water. It causes the disease dracunculiasis. The parasite has a two-host lifecycle, infecting humans and water fleas. People in rural areas who depend on open water sources for drinking are most at risk. Symptoms appear about a year after infection as a blister forms on the skin and the female worm emerges to release larvae into water, causing intense pain. Diagnosis involves detecting the emerging worm or larvae microscopically. Treatment focuses on slowly removing the worm and preventing secondary infections. Contaminated water prevention through filtration and use of boiled water is key to control.

1. Dracunculus medinensis
Presentation by:
Prazuna Bajgain
B.Sc.MLT 3rd year

2. CONTENTS
• Introduction
• Geographical distribution
• Habitat
• Morphology
• Life cycle
• Pathogenesis
• Host immunity
• Clinical features
• Laboratory diagnosis
• Treatment
• Prophylaxis

3. INTRODUCTION
DRACUNCULIASIS :
 Also known as guinea worm ,medina worm, dragon worm disease.
 Vector borne parasitic disease.
 Involves subcutaneous tissues(leg and foot).
 Caused by nematode parasite, Dracunculus medinensis.
 Its not lethal but disable its victim temporarily.
 Transmitted exclusively when people drink stagnant water contaminated with parasite infected water fleas.
 It affects people in rural, deprived and isolated communities who depend mainly on open surface water
sources such as ponds and wells.

4. The Guinea worm is found in predominantly in Africa from Senegal
(west) to Ethiopia (east).
Also found in India, Pakistan, Saudi Arabia, and Yemen.
• The majority of human infections occur in parts of West Africa, East
Africa, and India.

5. Habitat
 subcutaneous tissue specially part that contact
with water(foot ,leg, shoulder,and back)

6. Morphology
• One of the largest nematode known.
• They are milky white in colour.
• They are cylindrical and unsegmented.
• Adult females have been recorded to 1.20 m long.
• Males are shorter and some are known to grow to 40 mm

7. Adult female worm
 It is slender,long,60cm -1m in length and 0.9-1.7mm diameter
 The cuticle is smooth .
 The posterior end is blunt and bent to form a hook .
 The body of gravid female is virtually filled with the branches of an
enormous uterus that contain about 3 million embryos.
 It is viviparous .Life span is 1yr.

8. • Length : 0.01 – 0.04 m
• Diameter : 0.4 mm
• Mostly dies after fertilization.
• Posterior end of male is coiled.
Adult male worm

10. Larva
• Large ,measuring 500 -700 um in length. 5- 25 um in diameter.
• Anterior end is rounded
• Tail is pointed and long. Tail looks coiled bodies in wet preparation.
• Cuticle shows prominent striations.
• Larva swims about with a coiling and Uncoiling motion.

11. Host factor
• Man is the definitive host.
• Also infects dogs.
• Multiple and repeated infection may occur to same individual.
• No immunity is developed after prior infections
• Habit of bathing and drinking surface water makes them prone
to infections.
• Infection can occur to people of all age but young adults (15-
45)are mostly infected.

12. Host factor
• Copepods specially water flea act as the intermediate host.

13. Environmental factors
• Season:
– Infection mostly occur during the months from March to May from
the step wells.
– It is dry during this time.
– Contact between guinea worm and the source of drinking water is
very high.
– During June to September the source of infection is ponds

14. Environmental factors
• Temperature:
– Larva develop well between the temperature 25 to 30 deg. C.
– It will not develop below temperature 19 deg. C.
– Thus it is limited to tropical and sub tropical regions.

15. MODE OF TRANSMISSION
:
 Disease is transmitted entirely through the consumption of water
containing cyclops harboring the infective stage of the parasite.
 Guinea worm disease is a totally water-based disease.

16. Lifecycle
• Passes life cycle in two hosts :man and cyclops
Definitive Host -.Man .Harbours the adult parasite in the
subcutaneous tissues
Intermediate host-Cyclops, in which larvae undergo certain
development changes before they become infective to man.

17. Lifecycle
• First stage larvae are released by female into the water by the female
worm.
• Female releases millions of first stage larva into water.
• They remain in water for up to 1 weeks until they are ingested by suitable
copepods.
• Inside the copepods they moult twice to form third stage larvae which is
its infective form.

18. Lifecycle
• Infection to man takes place when the ingest the contaminated water
consisting of infected copepods.
• The copepod is dissolved by the digestive juices in stomach releasing
the third stage larvae.
• It penetrates the tissue through the duodenum and migrate to the
lower limb growing and developing there.

19. Lifecycle
• After three months the male mates and dies.
• Female continues to grow and travel down the muscle
planes.
• The female emerges after 10 to 14 months to release
millions of larvae in water to complete its lifecycle.

21. Pathogenesis
• SIGN/SYMPTOMS :
 Intense burning pain localized to path of travel of worm(the fiery serpent
 Fever
 Nausea
 Vomiting
 Allergic reaction
 Arthritis and paralysis (due to death of adult worm in joint).
 Skin blisters , which when rupture form ulcers
 Adult worms protrude from these ulcers.

23. Blister formation
• This occurs usually 1 year after infection
• Reddish spot or papule appears in the skin .
• In majority of the cases lower limbs are involved but it may also involve
umblicus ,grion, palm ,wrist and upper arm .
• The head of the gravid worms tries to come to the surface resulting in an
itching sensation at the area.

24. • The worm produces a toxin that converts the small red papule into a small
belb or blister of 2-7 cm
• The fluid in the blister contains bacteriologically sterile fluid lymphocyte
neutrophil eosinophil and larvae .
• Finally the blister ruptures revealings a small superficial erosion .
• The worm protudes its head through a small hole at the centre of the
erosion whenever the part of the body comes in contact with water.
• The central hole leads to a tunnel in the subcutaneous tissue where the
gravid female worm lies.
Contd…

27. Lab diagnosis
• Detection of adult worm:
• Gravid female appears at the surface of skin
• After death gets calcified and can be
detected radiologically.

28. Detection of larvae:
• Exposure to water releases large amount of larva.
• It is microscopically examined

29. Serology
• Antibody seen in serum by ELISA.
• It can also be demonstrated by fluorecents antibody test

30. Skin tests
• Antigen is injected intra dermally to see the allergic reactions.

31. Treatment
Removal of worm by:
Twisting it around the stick inch by inch for weeks to months.
Surgical removal
Metronidazole, niridazole are found effective in deworming
programmes .
Antibiotics are given to prevent secondary infection in ulcers.
Analgesics are given to reduce the pain.

32. Prevention
• Use of boileed water and filtered water.
• Patients should not be allowed to dip their legs in source of
drinking water.
• Use of insecticides to clean the stagnant water sources.
• Early detection and treatment of patients.

33. `
• Parasitology (K. D. Chatterjee 13th edition)
• Textbook of Medical Parasitology (Subhash Chandra Parija 2nd
edition)
REFERENCE