Explaining the Leak

An unexplained leak in a house can cause serious damage before the source is ever found. Ebola and Marburg viruses are deadly in part because they cause extreme diarrhoea, but until now it's been unclear how this happens. Researchers developed human gut organoids – mini guts grown in the lab – to investigate how these viruses attack the small intestine and colon. The viruses readily infected the organoids (pictured, red virus spreading in the colonic organoid one day (left) and three days (right) post-infection), and helps explain why symptoms are so severe. Infection disrupted the epithelial cells lining the gut, breaking down tight junctions and impairing ion (a charged atom or molecule) transport needed for normal fluid regulation. This leads to uncontrolled water loss and severe diarrhoea. The findings suggest that treatments protecting epithelial integrity or restoring ion transport could reduce symptoms and mortality, and the organoids provide a valuable platform for testing future therapies.

Written by Anthony Lewis

Anthony Lewis

Writer

Ant was the web editor in the early days of BPoD, and has since worked with the UK’s top science organisations as a writer and multimedia producer. He now splits his time between freelance work and managing multimedia at The Lancet.

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• Image from work by Elizabeth Y. Flores and colleagues
• Boston University Chobanian & Avedisian School of Medicine and Boston Medical Center, Boston, MA, USA
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in PLOS Pathogens, November 2025