The complex relationship of exposure to new Plasmodium infections and incidence of clinical malaria in Papua New Guinea
- Swiss Tropical and Public Health Institute, Switzerland
- Walter and Eliza Hall Institute of Medical Research, Australia
- Papua New Guinea Institute of Medical Research, Papua New Guinea
Abstract
The molecular force of blood-stage infection (molFOB) is a quantitative surrogate metric for malaria transmission at population level and for exposure at individual level. Relationships between molFOB, parasite prevalence and clinical incidence were assessed in a treatment-to-reinfection cohort, where P.vivax (Pv) hypnozoites were eliminated in half the children by primaquine (PQ). Discounting relapses, children acquired equal numbers of new P. falciparum (Pf) and Pv blood-stage infections/year (Pf-molFOB=0-18, Pv-molFOB=0-23) resulting in comparable spatial and temporal patterns in incidence and prevalence of infections. Including relapses, Pv-molFOB increased >3-fold (relative to PQ-treated children) showing greater heterogeneity at individual (Pv-molFOB=0-36) and village levels. Pf- and Pv-molFOB were strongly associated with clinical episode risk. Yearly Pf clinical incidence rate (IR=0.28) was higher than for Pv (IR=0.12) despite lower Pf-molFOB. These relationships between molFOB, clinical incidence and parasite prevalence reveal a comparable decline in Pf and Pv transmission that is normally hidden by the high burden of Pv relapses.
Article and author information
Author details
Funding
Swiss National Science Foundation (310030-134889 310030-159580)
- Ingrid Felger
- Ivo Mueller
National Institute of Allergy and Infectious Diseases (South West Pacific International Centers of Excellence in malaria research U19 AI089686)
- Inoni Betuela
- Ingrid Felger
- Leanne J Robinson
- Ivo Mueller
Bill and Melinda Gates Foundation
- Inoni Betuela
- Ingrid Felger
- Leanne J Robinson
- Ivo Mueller
National Health and Medical Research Council (Project Grant #1021544)
- Inoni Betuela
- Ingrid Felger
- Leanne J Robinson
- Ivo Mueller
Cellex Foundation
- Inoni Betuela
- Ivo Mueller
National Health and Medical Research Council (Early Career Fellowship #1016443)
- Leanne J Robinson
National Health and Medical Research Council (Early Career Fellowship #1052760)
- Stephan Karl
National Health and Medical Research Council (Senior Research Fellowship #1043345)
- Ivo Mueller
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Human subjects: The study received ethical clearance from the PNG IMR Institutional Review Board (0908), the PNG Medical Advisory Committee (09.11), the Ethics Committee of Basel 237/11 and was conducted in full concordance with the Declaration of Helsinki. Written informed consent was obtained from the parents/guardians of all children enrolled in the study.
Reviewing Editor
- Ben Cooper, Mahidol Oxford Tropical Medicine Research Unit, Thailand
Publication history
- Received: December 7, 2016
- Accepted: August 18, 2017
- Accepted Manuscript published: September 1, 2017 (version 1)
- Version of Record published: September 20, 2017 (version 2)
Copyright
© 2017, Hofmann et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Further reading
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- Epidemiology and Global Health
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- Epidemiology and Global Health
