Hookworm Infestation

An infestation of small, bloodsucking roundworms that may cause abdominal pain, cough, and fever

  • More common in children
  • Poor sanitation and inadequate personal hygiene are risk factors
  • Gender and genetics are not significant factors

The two main species of hookworms that can infest humans are Ancylostoma duodenale and Necator americanus. People are usually infested by direct contact with hookworm larvae (immature forms of the worm), which live in soil and can penetrate human skin. The larvae travel in the blood to the lungs and trachea (windpipe) and then to the intestines, where they develop into adult worms that can reach up to 1 cm ( 1 / 2 in) in length. The adults attach to the intestinal wall with hook-like teeth and feed by sucking blood from the wall. The female worms lay eggs, which pass out in the faeces of an affected person and develop into larvae in the soil.

Poor sanitation, inadequate personal hygiene, and the use of human faeces as fertilizer may increase the spread of the disorder. Hookworm is very common in tropical areas, affecting up to 1 in 2 people, especially children, at any one time. In the UK, people with hookworm have almost always acquired the infestation abroad through walking barefoot in water contaminated by sewage.

What are the symptoms?

In the early stages of hookworm infestation, the only symptom may be an itchy rash at the site where the larvae have pierced the skin. As the infestation progresses, symptoms may include:

  • Dry cough and mild fever due to the presence of larvae in the lungs.

  • Abdominal pain due to the presence of worms in the intestines.

Left untreated, large numbers of worms in the intestines may cause gradual, heavy blood loss, which may lead to iron-deficiency anaemia. If the anaemia is severe, it may cause chronic heart failure.


This magnified image shows the mouth of a hookworm. The “teeth” attach the worm to the wall of the intestine.

What might be done?

Your doctor will arrange for a sample of faeces to be examined for worm eggs if he or she suspects hookworm infestation. You will be given anthelmintic drugs to kill the worms and, if anaemia has developed, iron supplements. Rarely, if the anaemia is severe, a blood transfusion is necessary.

In order to prevent hookworm infestation when travelling in tropical and subtropical regions, you should wear waterproof shoes in villages and other populated areas if the ground is wet.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

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