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

By F Checchi, J A N Filipe, D T Haydon, D Chandramohan and F Chappuis


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 Médecins Sans Frontières 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

Publisher: BioMed Central
Year: 2008
DOI identifier: 10.1186/1471-2334-8-16
OAI identifier:
Provided by: MSF Field Research

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  1. (2000). [Persistence and resurgence of sleeping sickness caused by Trypanosoma brucei gambiense in historic foci. Biomathematical approach of an epidemiologic enigma].
  2. (1988). A general model for the African trypanosomiases. Parasitology
  3. (2006). Aparasitemic serological suspects in Trypanosoma brucei gambiense human African trypanosomiasis: a potential human reservoir of parasites? Acta Trop
  4. Clinical manifestations and diagnosis of sleeping sickness. In The African trypanosomiases first edition. Edited by: Mulligan HW. London: George Allen and Unwin Ltd;
  5. (1996). Control strategies for sleeping sickness in Central Africa: a model-based approach. Trop Med Int Health
  6. (1982). DD: Host susceptibility to African trypanosomiasis: trypanotolerance. Adv Parasitol
  7. (1995). De Muynck A: [Contribution of a mathematical model in the control of a parasitosis: the case of human African trypanosomiasis due to Trypanosoma brucei gambiense]. Ann Soc Belg Med Trop
  8. (2006). Diagnostic and neuropathogenesis issues in human African trypanosomiasis.
  9. (2005). Eflornithine is safer than melarsoprol for the treatment of second-stage Trypanosoma brucei gambiense human African trypanosomiasis. Clin Infect Dis
  10. (1997). Enyaru JC: Duration of symptoms and case fatality of sleeping sickness caused by Trypanosoma brucei rhodesiense in Tororo, Uganda. East Afr Med J
  11. (2000). Follow-up of Card Agglutination Trypanosomiasis Test (CATT) positive but apparently aparasitaemic individuals in Cote d'Ivoire: evidence for a complex and heterogeneous population. Trop Med Int Health
  12. (1995). Gastellu Etchegorry MG, Moren A: [Trypanosomiasis from Trypanosoma brucei gambiense in the center of north-west Uganda. Evaluation of 5 years of control (1987–1991)]. Bull Soc Pathol Exot
  13. (1978). Harndt I: Persistence of antibodies to Trypanosoma brucei gambiense after treatment of human trypanosomiasis in Uganda. Lancet cal diagnosis of T. B. gambiense trypanosomiasis. Ann Soc Belg Med Trop
  14. (2004). Human African trypanosomiasis: clinical presentation and immune response. Parasite Immunol
  15. Human African trypanosomiasis.
  16. INTCENS: Stata module to perform interval-censored survival analysis []
  17. (1999). Josenando T: Attitude towards CATT-positive individuals without parasitological confirmation in the African Trypanosomiasis (T.b. gambiense) focus of Quicama (Angola). Trop Med Int Health
  18. (1976). Le probleme du reservoir du virus et du mantien des foyers de trypanosomiase humaine en Afrique Centrale. Cah ORSTOM, ser Ent med et Parasitol
  19. Meirvenne N: A card-agglutination test with stained trypanosomes (C.A.T.T.) for the serologi-
  20. (2005). Options for field diagnosis of human african trypanosomiasis. Clin Microbiol Rev
  21. (2006). Organization: Human African trypanosomiasis (sleeping sickness): epidemiological update. Weekly Epidemiological Record
  22. (2005). Quantifying the level of under-detection of Trypanosoma brucei rhodesiense sleeping sickness cases. Trop Med Int Health
  23. (2004). Reanalyzing the 1900–1920 sleeping sickness epidemic in Uganda. Emerg Infect Dis
  24. (2001). S: Analysis of dynamic cohort data.
  25. (2003). S: Waking up to sleeping sickness. Trends Parasitol
  26. (2001). The epidemiology and control of human African trypanosomiasis. Adv Parasitol

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