Send to

Choose Destination
PLoS Biol. 2019 Jan 11;17(1):e3000105. doi: 10.1371/journal.pbio.3000105. [Epub ahead of print]

Resolving the apparent transmission paradox of African sleeping sickness.

Author information

Wellcome Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, United Kingdom.
Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom.
Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
Centre for Global Health, Usher Institute for Population Health Sciences and Bioinformatics, University of Edinburgh, Edinburgh, United Kingdom.
School of Veterinary Medicine, University of Glasgow, Glasgow, United Kingdom.
Unité Mixte de Recherche IRD-CIRAD 177, INTERTRYP, Institut de Recherche pour le Développement (IRD), Montpellier, France.
Programme National de Lutte contre la Trypanosomiase Humaine Africaine, Conakry, Guinea.
University of Kinshasa, Kinshasa, Democratic Republic of the Congo.
Trypanosome Transmission Group, Trypanosome Cell Biology Unit, INSERM U1201 and Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France.
Center for Infectious Disease Modeling and Analysis, Yale School of Public Health, New Haven, Connecticut, United States of America.


Human African trypanosomiasis (HAT), or African sleeping sickness, is a fatal disease found throughout sub-Saharan Africa. The disease is close to elimination in many areas, although it was similarly close to elimination once before and subsequently reemerged, despite seemingly low rates of transmission. Determining how these foci persisted and overcame an apparent transmission paradox is key to finally eliminating HAT. By assessing clinical, laboratory, and mathematical data, we propose that asymptomatic infections contribute to transmission through the presence of an overlooked reservoir of skin-dwelling parasites. Our assessment suggests that a combination of asymptomatic and parasitaemic cases is sufficient to maintain transmission at foci without animal reservoirs, and we argue that the current policy not to treat asymptomatic HAT should be reconsidered.

Free full text

Conflict of interest statement

The authors have declared that no competing interests exist.

Supplemental Content

Full text links

Icon for Public Library of Science
Loading ...
Support Center