Hookworm infection is caused by two types of hookworms i.e. Ancylostoma duodenal and Necator americanus. The anterior end of these worms is bent dorsally, hence it is known as hook worm. The male worm is shorter in length than female worm as male worm is about 8 to 10 mm in length and about 0.4 mm thick whereas female worm is about 10-13 mm in length and about 0.6 mm thick.
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A typical hookworm is almost cylindrical and threadlike with conical head and large oval mouth having four hooklike teeth on the upper side and two knobs like teeth on the lower side of the buccal cavity by which the worm fixes itself to mucous membrane of the intestines.
Mode of Transmission:
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A single female worm may lay 10,000 to 20,000 eggs per day which are passed in faeces. When they happen to be laid on warm moist soil the eggs hatch into larvae (in about 5 days time) outside the human body in the soil where they grow and develop into infective larvae. They can live in this stage for months when moisture and shade are available but are rapidly killed by drying.
When a person walks bare foot on the contaminated soil the infective larvae penetrate the skin and enter the body of healthy person. From skin they enter into the blood stream and are carried into the heart and from the heart into the lungs and reach upto trachea and pharynx from where they are swallowed.
After swallowing they enter the stomach from where finally they reach the small intestine where they develop into sexually mature worms and start laying eggs in about six weeks. It means an interval of about six weeks is required between the time of initial skin infection and the first appearance of eggs in the faeces. The adult worms attach themselves to the mucous membrane of the small intestines.
Ill-effects of Hookworm Infection:
It has been estimated that about 45 million people in India are suffering from hookworm infections. The ill-effects of this disease include iron deficiency anaemia, joint pains, abdominal pain, oedema, general weakness, loss of body resistance and decline in capacity to do hard work.
Prevention and Control:
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(i) Defecation in the open should be discouraged because when the moist soil is contaminated with faeces it leads to development of larvae of hookworm.
(ii) Night soil should be properly disposed of especially in rural and slum areas where chances of spread of this disease are more.
(iii) Use of sanitary latrines should be promoted in rural areas. This will prevent soil pollution.
(iv) As a personal protection the peasants working in the fields should wear shoes and gloves for prevention of hookworm infection.
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(v) Habit of walking bare-footed should be avoided.
(vi) Source of water supply should be protected from contamination with human excreta.
(vii) Public should be educated for proper use of sanitary latrines as well as personal hygiene specially washing hands after defecation and before taking meals.
In short, hookworm infection can be controlled by adopting sanitary measures, not defecating in the open, proper disposal of human excreta, wearing of shoes and imparting health education to the public.
Treatment:
For the treatment of hookworm infection various drugs are available which are quite effective against hookworm. These drugs include mebendazole, albendazole and pyrantal. In areas where hookworm infections are prevalent, community-oriented chemotherapy may be necessary. For the treatment of hookworm anaemia, iron and folic acid should be used and protein rich diet should be given to the patient.