Strongyloides stercoralis is a world wide human nematode,which is endemic in north of Iran. The forms of infection with strongyloides stercoralis varies from asymptomatic forms to life-threatening forms of the disease especially in immunocompromised hosts. Diagnosis can be made by detection of larvae in the stool,but routine stool examination may be negative,because larval output is irregular.Here we describe a case with unusual presentation of the disease.

Case report: A 78 years old man was referred to the gastroenterology clinic because of occult blood in stool. He reported no abdominal pain, weight loss, fatigue or other systemic symptoms and stool examination was obtained as annual screening evaluations. He had a history of well controlled hypertension on metoprolol. Laboratory investigations demonstrated a white blood cell count of 6.4 ×109/L with 9.4% eosinophils and a hemoglobin level of 13.9 g/L. Stool examination of three fecal samples was unremarkable except for positive occult blood in two samples. The results of routine laboratory testing, including liver and kidney function tests were normal. The patient underwent colonoscopy, which was unremarkable but gastroduodenoscopy revealed inflammation, erosions and small ulcers in first and second part of duodenum (figure1). The area of abnormality in Duodenum was biopsied, and the histology slide is shown in figure 2. Histologic examination showed mucosal injury with prominent eosionphilic infiltration and sections of Strongyloides stercoralis.

Strongyloides stercoralis is a worldwide human nematode,which is endemic in tropical and temperate climates. It is often asymptomatic or causes mild symptoms that involve the gastrointestinal tract, The disseminated and life-threatening forms of the disease are more commonly observed in immunocompromised hosts(1). Eosionophilia is seen in most infecected individuals. Diagnosis can be made by detection of larvae in the stool,but routine stool examination may be negative,because larval output is irregular. Histopathological identification of the parasite in tissue sections provides the definite diagnosis. Our patient had erosions and ulcers associated with Strongyloides stercoralis,he didn’t have any history of immunodeficiency.Although upper gastrointestinal ulcers induced by Strongyloides stercoralis are well described in Immunosuppressed patients, they are rarely reported in immunocompetent individuals and it seems that, index of suspicion of health care providers is low. The most anthelmintic drugs used to treat Strongyloides infection are ivermectin, albendazole and thiabendazole. The patient was treated with albendazole 400 mg orally twice daily for three days was found to be completely cured of Strongyloidiasis when the gastroduodenoscopy and duodenal biopsies were repeated after eight weeks.