Evaluating long-term effectiveness of sleeping sickness control measures in Guinea.
BACKGROUND
Human African Trypanosomiasis threatens human health across Africa. The subspecies T.b. gambiense is responsible for the vast majority of reported HAT cases. Over the past decade, expanded control efforts accomplished a substantial reduction in HAT transmission, spurring the WHO to include Gambian HAT on its roadmap for 2020 elimination. To inform the implementation of this elimination goal, we evaluated the likelihood that current control interventions will achieve the 2020 target in Boffa prefecture in Guinea, which has one of the highest prevalences for HAT in the country, and where vector control measures have been implemented in combination with the traditional screen and treat strategy.


METHODS
We developed a three-species mathematical model of HAT and used a Bayesian melding approach to calibrate the model to epidemiological and entomological data from Boffa. From the calibrated model, we generated the probabilistic predictions regarding the likelihood that the current HAT control programs could achieve elimination by 2020 in Boffa.


RESULTS
Our model projections indicate that if annual vector control is implemented in combination with annual or biennial active case detection and treatment, the probability of eliminating HAT as public health problem in Boffa by 2020 is over 90%. Annual implementation of vector control alone has a significant impact but a decreased chance of reaching the objective (77%). However, if the ongoing control efforts are interrupted, HAT will continue to remain a public health problem. In the presence of a non-human animal transmission reservoir, intervention strategies must be maintained at high coverage, even after 2020 elimination, to prevent HAT reemerging as a public health problem.


CONCLUSIONS
Complementing active screening and treatment with vector control has the potential to achieve the elimination target before 2020 in the Boffa focus. However, surveillance must continue after elimination to prevent reemergence.
Center for Infectious Disease Modeling and Analysis, Yale School of Public Health, New Haven, CT, 06510, USA.|Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06510, USA.
Abhishek
A
Pandey
HAT National Control Program, Ministry of Health, Conakry, Republic of Guinea. Katherine.Atkins@lshtm.ac.uk.
Katherine E
KE
Atkins
HAT National Control Program, Ministry of Health, Conakry, Republic of Guinea.|UMR INTERTRYP IRD/CIRAD, TA A 17/G, Campus International de Baillarguet, 34398, Montpellier, cedex 5, France.
Bruno
B
Bucheton
HAT National Control Program, Ministry of Health, Conakry, Republic of Guinea. mamadycamarafr@yahoo.fr.
Mamadou
M
Camara
Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06510, USA.
Serap
S
Aksoy
Center for Infectious Disease Modeling and Analysis, Yale School of Public Health, New Haven, CT, 06510, USA.|Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06510, USA.
Alison P
AP
Galvani
Center for Infectious Disease Modeling and Analysis, Yale School of Public Health, New Haven, CT, 06510, USA.|Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06510, USA.
Martial L
ML
Ndeffo-Mbah
D000818:Animals; D000981:Antiprotozoal Agents / Q000627:therapeutic use; D003140:Communicable Disease Control / Q000379:methods*; D060740:Disease Eradication; D018562:Disease Transmission, Infectious / Q000517:prevention & control*; D016701:Guinea / Q000453:epidemiology; D006302:Health Services Research; D006801:Humans; D008962:Models, Theoretical; D014353:Trypanosomiasis, African / Q000188:drug therapy / Q000453:epidemiology* / Q000517:prevention & control*
D000981:Antiprotozoal Agents