Ancylostoma duodenale

Ancylostoma duodenale is one of the most widespread intestinal parasites, affecting southern Europe, north Africa, north India, north China, Japan and the west coast of of south America. These hookworms are about a centimeter long and they hook themselves to the lining of the inside of your duodenum and suck your blood after cutting into the mucosa with their teeth.

The female worm lays eggs into the bowel which are then passed (depending on where you had a poo) onto the soil, where three larval stages are passed through in one week. They stay infective inside the soil for many months and, if contact is made, bore themselves into the skin and migrate in 3 days through your lymphatic system and bloodstream into your lungs.

Inside your lungs the larvae continues to mature and then climbs up through the alveolar tree towards the epiglottis, where it is swallowed and reaches your gut.

Tricky, ay? Most medical studens wouldn't be able to complete that feat, as they would probably get lost after the second or third arterial branch, but these worms seem to have their anatomy up to pretty high standards.

Most patients only notice the little guest when they are starting to become anaemic. The more worms are sucking away, the more haemoglobin you will obviously loose. Diagnosis is done by proving iron-deficiency anaemia and finding the characteristic eggs in your patients faeces. Treatment is with classic antihelmintics like mebendazole and is generally quick and harmless.

So, how do you avoid getting it? Not walking around with bare feet in areas where people tend to poo on the grounds because they can't afford loos is a start, as prevention is always better than treatment.

Eradicating poor hygiene and poor living conditions would be even better, so think about hookworms before you vote.

Dion R. Bell: Tropical Medicine, 4th Edition, Blackwell Science, 2000

Gwenlillian writes: hookworm-induced anemia was also the reason southern Blacks and rural Appalachians were characterized as 'lazy'.