Oral Presentation 8th International Conference on Plasmodium vivax Research 2022

Mathematical modelling of Plasmodium vivax to identify areas of residual transmission and effects of delayed treatment (80307)

Clara Champagne 1 2 , Maximilian Gerhards 1 2 , Justin Lana 3 , Bernardo García Espinosa 3 , Michael T White 4 , Emilie Pothin 1 2 3
  1. Swiss Tropical and Public Health Institute, Basel, BASEL, Switzerland
  2. University of Basel, Basel, Switzerland
  3. Clinton Health Access Initiative, Boston, USA
  4. Institut Pasteur, Paris, France

Plasmodium vivax’s distinguishing characteristics such as its ability to relapse and its early transmission potential increase its robustness in a wide range of environments, and thus complicate elimination efforts. With improved understanding of P. vivax dynamics, mathematical modelling can be used to estimate intrinsic risk and explore the potential impact of different interventions to support strategic planning. In this work, we build on a previously developed compartmental model for P. vivax dynamics, and expand it to allow its pragmatic uses to support strategic decisions. Firstly, the model is extended to account for imported infections, case management interventions targeting liver- or blood-stage parasites, and the effects of delayed treatment on onward transmission. Secondly, the model is embedded in a framework aimed at utilising routinely collected data on local and imported case counts to quantify transmission intensity through the calculation of local reproduction numbers. Available now as an R package to enhance country-specific applications, this model was used to identify areas of sustained malaria transmission in relatively low endemic areas but where transmission is not mainly importation-driven. When applied to various settings, substantial heterogeneity in local reproduction numbers was identified, especially depending on the amount of importation for a given number of reported cases. We also evaluated how localized targeting of interventions, such as down- or up-scaling community health programmes or reductions in treatment delay impacted overall malaria prevalence and case numbers. These results can help to identify which specific areas would benefit most from additional or strengthened case management. Hence, this model can be a useful tool to guide decision-making for P. vivax control.