Genetic diversity ofPlasmodium vivaxover time and space: a community-based study in rural Amazonia

Abstract

To examine how community-level genetic diversity of the malaria parasite Plasmodium vivax varies across time and space, we investigated the dynamics of parasite polymorphisms during the early phases of occupation of a frontier settlement in the Amazon Basin of Brazil. Microsatellite characterization of 84 isolates of P. vivax sampled over 3 years revealed a moderate-to-high genetic diversity (mean expected heterozygosity, 0.699), with a large proportion (78.5%) of multiple-clone infections (MCI), but also a strong multilocus linkage disequilibrium (LD) consistent with rare outcrossing. Little temporal and no spatial clustering was observed in the distribution of parasite haplotypes. A single microsatellite haplotype was shared by 3 parasites collected during an outbreak; all other 81 haplotypes were recovered only once. The lowest parasite diversity, with the smallest proportion of MCI and the strongest LD, was observed at the time of the outbreak, providing a clear example of epidemic population structure in a human pathogen. Population genetic parameters returned to pre-outbreak values during last 2 years of study, despite the concomitant decline in malaria incidence. We suggest that parasite genotyping can be useful for tracking the spread of new parasite strains associated with outbreaks in areas approaching malaria elimination.

Frequent Spread of Plasmodium vivax Malaria Maintains High Genetic Diversity at the Myanmar-China Border, Without Distance and Landscape Barriers

“…Compared with other malaria-hypoendemic areas, such as Vietnam (71.4%; [40]), Sri Lanka (68%; [37]), Colombia (60-80%; [41]), and the Amazon Basin in Brazil (50%; [42]), the proportion of polyclonal infections among our samples was relatively low (29%). Our study sites represent a modest transmission area at the Myanmar-China border region.…”

Higher Complexity of Infection and Genetic Diversity of Plasmodium vivax Than Plasmodium falciparum Across All Malaria Transmission Zones of Papua New Guinea

“…33,[50][51][52] The complexity of infection was somewhat variable among different regions and geographic clusters for both species, and is comparable to that found in a wide range of higher transmission settings in other countries. 27,28,33,38,[53][54][55][56][57] However, the vast majority of P. vivax infections were polyclonal and MOI was almost 2-fold higher than that of P. falciparum. Furthermore, although complexity of infection was associated with prevalence for P. falciparum, there was no association between these parameters for P. vivax.…”

Reactive Case Detection for Plasmodium vivax Malaria Elimination in Rural Amazonia

“…To the contrary, we characterized a highly diverse P . vivax population in our study site as well as in endemic settings nearby [38–40], with a wide variety of strains co-circulating not only in the proximity of index cases but also in the surrounding HHs outside the clusters. Accordingly, nearly two thirds of the genotypes circulating within each cluster were unique, consistent with a continuous introduction of new parasite strains and little onward transmission of these strains to neighboring individuals over the following months.…”