A case of Strongyloides hyperinfection syndrome in the setting of persistent eosinophilia but negative serology

Strongyloides stercoralis is a unique intestinal nematode with the ability to replicate and complete its life cycle without leaving the host. We report a fatal case of Strongyloides hyperinfection syndrome in a patient who had persistent eosinophilia for several years but negative Strongyloides serology. Our case suggests that ELISA serologies cannot solely be relied upon to diagnose Strongyloides stercoralis infection; history and clinical judgment remain crucial to this diagnosis.