Discussion Strongyloides stercoralis infestation is common in the tropical and sub-tropical areas of the world. In the United States, it is endemic in southern parts and can be often isolated from residents of mental institutions who have poor hygiene and from immigrants, or military veterans who have lived in endemic regions. The helminth lives in the small intestinal mucosa in most of the uncomplicated cases. It is characterized by its unusual capacity to replicate within the human host, thereby enabling perpetual autoinfection cycles due to internal production of infective larvae. The parasite also can tolerate a free-living cycle of development in the soil.
Humans acquire strongyloidiasis following contact with contaminated soil.
The filariform larvae penetrate the skin or mucous membranes. They then travel through the bloodstream to the lungs, where theypenetrate into the alveolar spaces, ascend the bronchial tree, and then, are swallowed down to reach the small intestine. Larvae have been found in several unusual sites, such as the skin 5,13 and the cerebrospinal fluid 2,6 in the disseminated forms of the disease. However, only a few reports indicate the observation of parasitic larvae in the mucosal lining of the stomach. Normand was the first to describe Strongyloides stercoralis as a pathogenic helminth of humans, in 1876.