Dracunculas Medinensis

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