Infection with Isospora belli is a well-known cause of chronic diarrhea in patients with human immunodeficiency virus/acquired immunodeficiency syndrome. Recurrent isosporiasis, causing chronic diarrhea in human immunodeficiency virus–seronegative individuals, should lead to a search for other causes of immunosuppression, including human T-cell lymphotropic virus 1 infection.
From the *Division of Infectious Diseases, †Department of Internal Medicine, Maimonides Medical Center ‡Division of Infectious Diseases, SUNY Downstate Medical Center, and §Department of Pathology and Laboratory Medicine, Maimonides Medical Center, Brooklyn, NY.
Correspondence to: Purba Gupta, MD, Maimonides Medical Center, 4802 10th Ave, Brooklyn, NY 11219. E-mail: email@example.com.
Alternate corresponding author: Monica Ghitan, Maimonides Medical Center, 4802 10th Ave, Brooklyn, NY 11219; E mail: firstname.lastname@example.org.
The authors have no funding or conflicts of interest to disclose.