Abstracts (first author)
Why anti-malarial drug resistance is spreading faster in Plasmodium falciparum than in Plasmodium vivax
Affiliation: Full Professor, University of applied Sciences Mittweida, Germany
Abstract: Drug treatments - in the absence of vaccines - are a major component of malaria control program. The two human malaria agents, P. falciparum and P. vivax, causing the most morbidity and mortality have distinct characteristics that affect their treatments. Considering these species-specific differences is crucial for control and elimination efforts. Particularly, the rapid evolution of drug-resistant P. falciparum is currently a source of concern for global health. A complex compound of particular steps (fitness components) in the malaria life cycle determines evolutionary fitness of drug-resistance-conferring mutations. Differences in fitness components affect how selection imposed by interventions, e.g. drug treatments, differentially acts on each Plasmodium species. We formulate a population-genetic model that explains how different fitness components affect selection for drug resistance, focusing on: (i) characteristics of sexual parasite life stages responsible for host-to vector transmission; and (ii) presence of dormant liver-stage parasites. The model explains why drug-resistance is evolving much faster in P. falciparum than in P. vivax. The model’s data-driven nature (i.e., parameters can be estimated from molecular data) has the potential to facilitate new experimental designs to better understand drug-resistance evolution in terms of clinically measurable quantities. A successful malaria control/elimination program should incorporate how differences in fitness components across malaria species affect adaptive evolution (e.g. the emergence of drug resistance).
Reference: Schneider, KA, Escalante, AA (2013). Fitness components and natural selection: why are there different patterns on the emergence of drug resistance in P. falciparum and P. vivax? Malaria J. 12: 15.