Parasite-perverted Immunity

Nodding syndrome is a rare and poorly understood disease in which children become afflicted with characteristic head-bobbing seizures (hence the name), stunted growth and mental and physical disability. The condition was first identified in Tanzania in the 1960s, but the cause of this debilitating and distressing disease has remained a mystery. Researchers have long suspected that the parasitic worm Onchocerca volvulus(pictured), which also causes river blindness, might be involved because most nodding syndrome sufferers also have O. volvulus infections. New studies reveal that while the worm does not cause nodding syndrome directly, the body’s reaction to the parasite leads inadvertently to brain damage. Antibodies created by the immune system against proteins in the worm cross-react with host proteins in the brain causing cell death. The findings suggest that patients with this parasite-triggered disease may benefit from immunosuppressive therapies.

Written by Ruth Williams

Ruth Williams

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Ruth is a freelance science journalist based in the US. She's a regular correspondent for The Scientist, and her work has appeared in The Lancet, Nature, Scientific American Mind, BBC Focus and elsewhere. Twitter @rooph

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• Image courtesy of Dr. Thomas B. Nutman, Laboratory of Parasitic Diseases, NIAID, NIH
• Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
• Image copyright held by the photographer
• Research published in Science Translational Medicine, February 2017