Lessons from the “Urbanorum spp.” controversy: a supposed parasite and the need for scientific rigor and quality research in Latin America

BACKGROUND Despite insufficient parasitological and clinical evidence, infections attributed to a putative protozoan named “Urbanorum spp.” have been associated with gastrointestinal disease and treated with anti-parasitic drugs. OBJECTIVES This study aimed to clarify the nature of “Urbanorum spp.” and provide guidance for health and biomedical professionals encountering this structure in human stool, emphasising the importance of rigor and quality in biomedical research. METHODS Coprological analyses were employed to detect intestinal parasites, lipids, and “Urbanorum spp.” in 249 samples. Samples positive for “Urbanorum spp.” underwent staining with trichrome, acid-fast, and Sudan IV and contrasted with positive controls. Examination with polarised light microscopy and a fragility test using ethanol were conducted. FINDINGS Of the tested samples, 19.4%, 2.5% and 1.3% were positive for intestinal parasites, lipids, and “Urbanorum spp.” respectively. Following trichrome and acid-fast staining, few “Urbanorum spp.” structures remained intact and exhibited no discernible eukaryotic characteristics; Sudan IV stain, polarized light microscopy and fragility test approaches indicated a cholesterol-based content. MAIN CONCLUSIONS “Urbanorum spp.” is not a protozoan parasite; therefore, antiparasitic drugs are unwarranted. This structure should be identified as lipid-based material and investigated for possible malabsorption syndrome. Rigorous scientific standards were missed in related publications and peer review, contributing to the spread of this pseudoparasitism case.