Dracunculiasis or guinea worm disease is a
vector-borne parasitic disease, mainly of the subcutaneous tissues (usually leg
and foot) caused by the nematode parasite, Dracunculus medinensis. This
parasitic disease can disable its victims temporarily.
vector-borne parasitic disease, mainly of the subcutaneous tissues (usually leg
and foot) caused by the nematode parasite, Dracunculus medinensis. This
parasitic disease can disable its victims temporarily.
Natural History
Agent: The adult parasite inhabits the subcutaneous tissue
mainly of the legs but of other parts of the body, including the head and neck.
The gravid female makes her way down to the infected person’s lower limbs near
the skin surface. She penetrates into the dermis and induces an inflammatory
reaction and subsequent blister formation. Upon contact with water, the blister
soon ruptures and the parasite release up to one million, microscopic,
free-swimming larvae into water. The larvae may remain active in water for 3 –
6 days. They are picked up by small fresh-water crustaceans called cyclops. The
larvae require a period of about 15 days for development in cyclops, which is
the intermediate host.
mainly of the legs but of other parts of the body, including the head and neck.
The gravid female makes her way down to the infected person’s lower limbs near
the skin surface. She penetrates into the dermis and induces an inflammatory
reaction and subsequent blister formation. Upon contact with water, the blister
soon ruptures and the parasite release up to one million, microscopic,
free-swimming larvae into water. The larvae may remain active in water for 3 –
6 days. They are picked up by small fresh-water crustaceans called cyclops. The
larvae require a period of about 15 days for development in cyclops, which is
the intermediate host.
Man acquires infection by
drinking water containing infected cyclops. In the human body, digested by
gastric juice, the parasites are released. They penetrate the duodenal wall.
Subsequently, they migrate through the viscera to the subcutaneous tissues of
various parts of the body.
drinking water containing infected cyclops. In the human body, digested by
gastric juice, the parasites are released. They penetrate the duodenal wall.
Subsequently, they migrate through the viscera to the subcutaneous tissues of
various parts of the body.
Reservoir of Infection: An infected person
harbouring the gravid female. The possibility of an animal reservoir exists but
not proved.
harbouring the gravid female. The possibility of an animal reservoir exists but
not proved.
Host Factors: Host susceptibility is
universal. Multiple and repeated infections may occur in the same individual.
The habit of washing and batting in surface water and using step-wells is
important.
universal. Multiple and repeated infections may occur in the same individual.
The habit of washing and batting in surface water and using step-wells is
important.
Environmental Factors: The main link of
transmission of guinea worm disease is water infected with cyclop. The risk of
transmission exists where such cyclops infested water sources are frequented by
infected person.
transmission of guinea worm disease is water infected with cyclop. The risk of
transmission exists where such cyclops infested water sources are frequented by
infected person.
Mode of Transmission: the disease is transmitted
entirely through the consumption of water containing cyclops harbouring the
infective stages of the parasite. Guinea worm disease is a totally water-based
disease and does not have an alternative pathway of transmission.
entirely through the consumption of water containing cyclops harbouring the
infective stages of the parasite. Guinea worm disease is a totally water-based
disease and does not have an alternative pathway of transmission.
Preventing/Control Measures
1. Provide portable water.
Abolish step-wells and take other measures, such as the use of occlusive
bandages to prevent contamination of drinking water by infected persons
immersing feet or other parts of the affected body in water.
Abolish step-wells and take other measures, such as the use of occlusive
bandages to prevent contamination of drinking water by infected persons
immersing feet or other parts of the affected body in water.
2. Boil drinking water, filter
through fine mesh cloths to remove cyclops.
through fine mesh cloths to remove cyclops.
3. Educate the public to drink
only boiled and filtered water from the close or pump-well. Instruct infected
person on mode of spread of infection and the danger in contaminating wells or
other water supplies.
only boiled and filtered water from the close or pump-well. Instruct infected
person on mode of spread of infection and the danger in contaminating wells or
other water supplies.