A model for malaria treatment evaluation in the presence of multiple species
Issued Date
2023-09-01
Resource Type
ISSN
17554365
eISSN
18780067
Scopus ID
2-s2.0-85162246774
Journal Title
Epidemics
Volume
44
Rights Holder(s)
SCOPUS
Bibliographic Citation
Epidemics Vol.44 (2023)
Suggested Citation
Walker C.R., Hickson R.I., Chang E., Ngor P., Sovannaroth S., Simpson J.A., Price D.J., McCaw J.M., Price R.N., Flegg J.A., Devine A. A model for malaria treatment evaluation in the presence of multiple species. Epidemics Vol.44 (2023). doi:10.1016/j.epidem.2023.100687 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/87698
Title
A model for malaria treatment evaluation in the presence of multiple species
Author's Affiliation
Mahidol Oxford Tropical Medicine Research Unit
Melbourne School of Population and Global Health
The Peter Doherty Institute for Infection and Immunity
Commonwealth Scientific and Industrial Research Organization
University of Melbourne
Menzies School of Health Research
James Cook University
Nuffield Department of Medicine
Cambodian National Center for Parasitology
Melbourne School of Population and Global Health
The Peter Doherty Institute for Infection and Immunity
Commonwealth Scientific and Industrial Research Organization
University of Melbourne
Menzies School of Health Research
James Cook University
Nuffield Department of Medicine
Cambodian National Center for Parasitology
Other Contributor(s)
Abstract
Plasmodium falciparum and P. vivax are the two most common causes of malaria. While the majority of deaths and severe morbidity are due to P. falciparum, P. vivax poses a greater challenge to eliminating malaria outside of Africa due to its ability to form latent liver stage parasites (hypnozoites), which can cause relapsing episodes within an individual patient. In areas where P. falciparum and P. vivax are co-endemic, individuals can carry parasites of both species simultaneously. These mixed infections complicate dynamics in several ways: treatment of mixed infections will simultaneously affect both species, P. falciparum can mask the detection of P. vivax, and it has been hypothesised that clearing P. falciparum may trigger a relapse of dormant P. vivax. When mixed infections are treated for only blood-stage parasites, patients are at risk of relapse infections due to P. vivax hypnozoites. We present a stochastic mathematical model that captures interactions between P. falciparum and P. vivax, and incorporates both standard schizonticidal treatment (which targets blood-stage parasites) and radical cure treatment (which additionally targets liver-stage parasites). We apply this model via a hypothetical simulation study to assess the implications of different treatment coverages of radical cure for mixed and P. vivax infections and a “unified radical cure” treatment strategy where P. falciparum, P. vivax and mixed infections all receive radical cure after screening glucose-6-phosphate dehydrogenase (G6PD) normal. In addition, we investigated the impact of Mass Drug Administration (MDA) of blood-stage treatment. We find that a unified radical cure strategy leads to a substantially lower incidence of malaria cases and deaths overall. MDA with schizonticidal treatment was found to decrease P. falciparum with little effect on P. vivax. We perform a univariate sensitivity analysis to highlight important model parameters.