The skin is a significant but overlooked anatomical reservoir for vector-borne African trypanosomes

• Main Authors: Paul Capewell, Christelle Cren-Travaillé, Francesco Marchesi, Pamela Johnston, Caroline Clucas, Robert A Benson, Taylor-Anne Gorman, Estefania Calvo-Alvarez, Aline Crouzols, Grégory Jouvion, Vincent Jamonneau, William Weir, M Lynn Stevenson, Kerry O'Neill, Anneli Cooper, Nono-raymond Kuispond Swar, Bruno Bucheton, Dieudonné Mumba Ngoyi, Paul Garside, Brice Rotureau, Annette MacLeod
• Format: Article
• Language: English
• Published: eLife Sciences Publications Ltd 2016-09-01
• Series: eLife
• Subjects: Human African Trypanosomiasis; skin; reservoir; transmission; trypanosomes; Trypanosoma brucei gambiense
• Online Access: https://elifesciences.org/articles/17716

The role of mammalian skin in harbouring and transmitting arthropod-borne protozoan parasites has been overlooked for decades as these pathogens have been regarded primarily as blood-dwelling organisms. Intriguingly, infections with low or undetected blood parasites are common, particularly in the case of Human African Trypanosomiasis caused by Trypanosoma brucei gambiense. We hypothesise, therefore, the skin represents an anatomic reservoir of infection. Here we definitively show that substantial quantities of trypanosomes exist within the skin following experimental infection, which can be transmitted to the tsetse vector, even in the absence of detectable parasitaemia. Importantly, we demonstrate the presence of extravascular parasites in human skin biopsies from undiagnosed individuals. The identification of this novel reservoir requires a re-evaluation of current diagnostic methods and control policies. More broadly, our results indicate that transmission is a key evolutionary force driving parasite extravasation that could further result in tissue invasion-dependent pathology.