Strongyloidiasis

In humans strongyloides stercoralis (intestinalis) is particularly significant. It is a roundworm, occurring widely in tropical and subtropical countries. The female worm and her larvae inhabit the mucosa and submucosa of the small intestine where they cause diarrhoea and ulceration. Larvae expelled from an infected person with the faeces develop in the soil and penetrate human skin on contact. They eventually are carried with the blood stream to the lungs, where they cause haemorrhage when they rupture into the alveoli. They reach the intestines from the lungs via the trachea and the oesophagus.

Infection with strongyloides stercoralis is particularly common in immunosuppressed patients whereas in others the infection is frequently asymptomatic. In the early stages of strongyloidiasis barium studies will reveal thickened mucosal folds due to oedema in stomach, duodenum and jejunum. In the small bowel decreased motility and dilatation may be seen. In the later stages of the disease ulceration may be present. The bowel wall becomes fibrosed and more rigid, with obliteration of the normal fold pattern and absence of peristalsis. This rigid appearance has been termed "lead pipe" or "pipe stem" appearance.

ALB