Estimates of the duration of the early and late stage of gambiense sleeping sickness

Checchi, F., Filipe, J.A., Haydon, D.T., Chandramohan, D. and Chappuis, F. (2008) Estimates of the duration of the early and late stage of gambiense sleeping sickness. BMC Infectious Diseases, 8(16), (doi: 10.1186/1471-2334-8-16)

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Background: The durations of untreated stage 1 (early stage, haemo-lymphatic) and stage 2 (late stage, meningo-encephalitic) human African trypanosomiasis (sleeping sickness) due to Trypanosoma brucei gambiense are poorly quantified, but key to predicting the impact of screening on transmission. Here, we outline a method to estimate these parameters. Methods: We first model the duration of stage 1 through survival analysis of untreated serological suspects detected during Medecins Sans Frontieres interventions in Uganda and Sudan. We then deduce the duration of stage 2 based on the stage 1 to stage 2 ratio observed during active case detection in villages within the same sites. Results: Survival in stage 1 appears to decay exponentially (daily rate = 0.0019; mean stage 1 duration = 526 days [ 95% CI 357 to 833]), possibly explaining past reports of abnormally long duration. Assuming epidemiological equilibrium, we estimate a similar duration of stage 2 (500 days [ 95% CI 345 to 769]), for a total of nearly three years in the absence of treatment. Conclusion: Robust estimates of these basic epidemiological parameters are essential to formulating a quantitative understanding of sleeping sickness dynamics, and will facilitate the evaluation of different possible control strategies

Item Type:Articles
Glasgow Author(s) Enlighten ID:Haydon, Professor Daniel
Authors: Checchi, F., Filipe, J.A., Haydon, D.T., Chandramohan, D., and Chappuis, F.
Subjects:R Medicine > RA Public aspects of medicine
R Medicine > RC Internal medicine
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
Journal Name:BMC Infectious Diseases

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