Symptomatic Chronic Strongyloides Stercoralis Infection after Roux-en-Y Gastric Bypass in an Immunocompetent Patient

Strongyloides stercoralis is a parasitic nematode with a unique auto infective life cycle, enabling persistent infection. While infection can remain asymptomatic for decades, factors such as malnutrition may facilitate the transition to symptomatic strongyloides infection. Roux-en-Y gastric bypass (RYGB) induce malnutrition due to reduced intake and impaired nutrient absorption.

A 31-year-old male presented with nausea, diarrhoea, and general malaise following RYGB six months earlier. Jejunal biopsy and faecal polymerase chain reaction (PCR) confirmed chronic S. stercoralis infection, likely acquired during travel to Bali in 2016. Treatment with ivermectin led to rapid clinical improvement, normalization of eosinophil counts, and negative faecal PCR within four weeks.

Chronic S. stercoralis infection may become symptomatic following RYGB, likely due to postoperative physiological changes, such as malnutrition. Malabsorption, particularly zinc deficiency, may impair mucosal immunity and facilitate parasite persistence. Additionally, reduced colonic motility and gastric acid secretion post-RYGB may compromise host defence mechanisms, increasing the risk of transformation to symptomatic infection. These findings suggest that preoperative screening for S. stercoralis might be considered in bariatric candidates with prior exposure to endemic regions. Further research is warranted to clarify the pathophysiological mechanisms linking bariatric surgery to reactivation of chronic strongyloidiasis.

This case suggests that malnutrition, reduced gastric acid, and altered gut motility after Roux-en-Y gastric bypass (RYGB), might impair parasite clearance and immunity, turning an asymptomatic chronic infection into a clinical threat.The findings of this case suggest that preoperative screening in bariatric surgery candidates with relevant travel history related to S. stercoralis could be useful as RYGB may elevate risk for parasitic flare-ups.