Filariform larva - Strongyloides stercoralis

Filter preparation of bronchoalveolar lavage (BAL) fluid stained with Papanicolaou Transmitted light microscopy. Three focal planes fused. Strongyloidiasis is caused by infection with the nematode S. stercoralis. The initial infection involves penetration of the skin my filariform larvae, circulation of the organism to the lungs and subsequent involvement of the gastrointestinal tract. Internal autoinfection is exaggerated in hyperinfection syndrome and in some immunosuppressed individuals dissemination beyond the GI tract, skin and lungs may occur. This image of a filariform larva was obtained from a Papanicolaou stained filter preparation of bronchoalveolar lavage fluid in a patient receiving steroids for severe inflammatory bowel disease. Typically the presence of these parasites would cause numerous eosinophils to accumulate but in this case eosinophils were suppressed by steroids and only scattered lymphocytes and neutrophils are present around the larva. Image width 215 microns