Contrasting Transmission Dynamics of Co-endemic Plasmodium vivax and P. falciparum: Implications for Malaria Control and Elimination

Published: May 7, 2015

Citation

Noviyanti R, Coutrier F, Utami RA, Trimarsanto H, Tirta YK, Trianty L, Kusuma A, Sutanto I, Kosasih A, Kusriastuti R, Hawley WA, Laihad F, Lobo N, Marfurt J, Clark TG, Price RN, Auburn S. Contrasting Transmission Dynamics of Co-endemic Plasmodium vivax and P. falciparum: Implications for Malaria Control and Elimination. PLoS Negl Trop Dis, 2015; 9(5):e0003739, 2015. doi: 10.1371/journal.pntd.0003739

Abstract

Background

Outside of Africa, Pfalciparum and Pvivax usually coexist. In such co-endemic regions, successful malaria control programs have a greater impact on reducing falciparum malaria, resulting in Pvivaxbecoming the predominant species of infection. Adding to the challenges of elimination, the dormant liver stage complicates efforts to monitor the impact of ongoing interventions against Pvivax. We investigated molecular approaches to inform the respective transmission dynamics of Pfalciparum and Pvivax and how these could help to prioritize public health interventions.

Methodology/ Principal Findings

Genotype data generated at 8 and 9 microsatellite loci were analysed in 168 Pfalciparum and 166 Pvivaxisolates, respectively, from four co-endemic sites in Indonesia (Bangka, Kalimantan, Sumba and West Timor). Measures of diversity, linkage disequilibrium (LD) and population structure were used to gauge the transmission dynamics of each species in each setting. Marked differences were observed in the diversity and population structure of Pvivax versus Pfalciparum. In Bangka, Kalimantan and Timor, Pfalciparumdiversity was low, and LD patterns were consistent with unstable, epidemic transmission, amenable to targeted intervention. In contrast, Pvivax diversity was higher and transmission appeared more stable. Population differentiation was lower in Pvivax versus Pfalciparum, suggesting that the hypnozoite reservoir might play an important role in sustaining local transmission and facilitating the spread of Pvivax infections in different endemic settings. Pvivax polyclonality varied with local endemicity, demonstrating potential utility in informing on transmission intensity in this species.

Conclusions/ Significance

Molecular approaches can provide important information on malaria transmission that is not readily available from traditional epidemiological measures. Elucidation of the transmission dynamics circulating in a given setting will have a major role in prioritising malaria control strategies, particularly against the relatively neglected non-falciparum species.