Transmission intensity and Plasmodium falciparum diversity on the northwestern border of Thailand.

Rácz, Paul; Hackford, I.; Brockman, Alan; Müller‐Graf, Christine; Price, Richard; Luxemburger, Christine; White, Nicholas J.; Nosten, François; Day, Karen P.

doi:10.4269/ajtmh.1998.58.195

Cited by 89 publications

(77 citation statements)

References 38 publications

(68 reference statements)

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“…This evidence suggests that more recent selective forces have shaped population structure in this species. Previous studies also suggest that P. falciparum infections in Southeast Asia were more multiclonal two decades ago, again suggesting that recent forces have constrained its genetic diversification (75)(76)(77). This evidence is consistent with our findings that P. falciparum in Cambodia has undergone large demographic shifts much more recently than P. vivax.…”

Section: Discussionsupporting

confidence: 83%

Selective sweep suggests transcriptional regulation may underlie Plasmodium vivax resilience to malaria control measures in Cambodia

Parobek

Lin

Saunders

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Cambodia, in which both Plasmodium vivax and Plasmodium falciparum are endemic, has been the focus of numerous malaria-control interventions, resulting in a marked decline in overall malaria incidence. Despite this decline, the number of P. vivax cases has actually increased. To understand better the factors underlying this resilience, we compared the genetic responses of the two species to recent selective pressures. We sequenced and studied the genomes of 70 P. vivax and 80 P. falciparum isolates collected between 2009 and 2013. We found that although P. falciparum has undergone population fracturing, the coendemic P. vivax population has grown undisrupted, resulting in a larger effective population size, no discernable population structure, and frequent multiclonal infections. Signatures of selection suggest recent, species-specific evolutionary differences. Particularly, in contrast to P. falciparum, P. vivax transcription factors, chromatin modifiers, and histone deacetylases have undergone strong directional selection, including a particularly strong selective sweep at an AP2 transcription factor. Together, our findings point to different population-level adaptive mechanisms used by P. vivax and P. falciparum parasites. Although population substructuring in P. falciparum has resulted in clonal outgrowths of resistant parasites, P. vivax may use a nuanced transcriptional regulatory approach to population maintenance, enabling it to preserve a larger, more diverse population better suited to facing selective threats. We conclude that transcriptional control may underlie P. vivax's resilience to malaria control measures. Novel strategies to target such processes are likely required to eradicate P. vivax and achieve malaria elimination.D uring the last decade, western Cambodia has been the focus of numerous and multimodal interventions to control the spread of artemisinin-resistant Plasmodium falciparum (1, 2). Such interventions, including increased vector control, increased surveillance, and improved access to quality artemisinin-combination therapy (ACT), would be expected to curtail coendemic Plasmodium vivax as well. However, even as P. falciparum infections in Cambodia decreased by 81% between 2009 and 2013, P. vivax cases have increased, making it the predominant species in the Mekong region (3-6). This scenario, repeated in Brazil and other areas of coendemicity, has led to growing awareness that P. vivax, although infecting the same populations and transmitted by the same mosquito vectors, will likely be the more challenging species to eradicate (6-9). In this study, we use population genomics to gain insight into the evolutionary factors underlying P. vivax's resilience to malaria control measures.Population genetic studies have previously hinted at the resilience of P. vivax populations in comparison with P. falciparum. Studies of microsatellites and highly variable antigens of sympatric P. vivax and P. falciparum populations in Southeast Asia and the Southwest Pacific have consistently shown P. viv...

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Section: Discussionsupporting

confidence: 83%

Selective sweep suggests transcriptional regulation may underlie Plasmodium vivax resilience to malaria control measures in Cambodia

Parobek

Lin

Saunders

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…Genetic variation in areas of hyperendemicity has been found to be greater than that in areas of hypoendemicity (1,18). Previous studies of the genetic variation within the polymorphic region of PvMSP-1 showed several patterns among the isolates.…”

Section: Discussionmentioning

confidence: 99%

Molecular Genetic Characterization of the Merozoite Surface Protein 1 Gene of Plasmodium vivax from Reemerging Korean Isolates

Kim¹,

Hwang²,

Shin³

et al. 2009

Clin Vaccine Immunol

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Plasmodium vivax merozoite surface protein 1 (PvMSP-1) has been considered a major candidate for the development of an antimalaria vaccine, but the molecule exhibits antigenic diversity among isolates. The extent of genetic polymorphism in the region between interspecies conserved blocks 4 and 5 (ICB4 and ICB5) of the PvMSP-1 gene was analyzed for 30 Korean isolates. Two genotypes, SK-A and SK-B, were identified on the basis of amino acid substitution. Almost all the amino acid sequences of the Korean isolates were nearly identical to those of the Solomon Island isolate Solo-83 (97.8 to 99.9% similarity) and Philippine isolates Ph-79, Ph-52-2, and Ph-49 (97.3 to 99.8% similarity). Also, we report two sequences in the isolates that were characterized on the basis of restriction fragment length polymorphism (RFLP). The RFLP profiles following digestion with the DraI restriction enzyme produced two distinguishable patterns. This study might be the first report of the region between ICB4 and ICB5 of the MSP-1 gene of P. vivax in South Korea.

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“…However, based on empirical data indicating that genetic variation is substantial both within and between infections in other Plasmodium species (Babiker & Walliker 1997;Paul et al 1998;Konate et al 1999;Smith et al 1999), we favour a genetic explanation for variation between donor groups. However, we were unable to distinguish between genotype di¡erences between donor infections or di¡erences due to competition between clones.…”

Section: Discussionmentioning

confidence: 99%

Life history of a malaria parasite (Plasmodium mexicanum): independent traits and basis for variation

Eisen

Schall

2000

Proc. R. Soc. Lond. B

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Plasmodium mexicanum, a malaria parasite of lizards, exhibits substantial variation among infections in the life-history traits which de¢ne its blood-dwelling stages. Such variation in life histories among infections is common in Plasmodium and may in£uence the ecology and evolution of the parasite's transmission success and virulence. Insight into these issues requires identi¢cation of independent traits (some traits may be bound by developmental trade-o¡s) and the importance of genetic versus host e¡ects producing the variation. We studied 11 life-history traits in 120 induced infections of P. mexicanum in its natural lizard host (20 each from six donor infections). The traits varied among infections and fell into three clusters: rate/peak (rate of increase and peak parasitaemia of asexuals and gametocytes), time (duration of prepatent period and the infection's growth) and maturity (timing of ¢rst gametocytes). Thus, few lifehistory traits de¢ne an infection in the lizard's blood. Donor e¡ects were signi¢cant for ten traits and two trait clusters (maturity was the exception) suggesting genetic di¡erences among infections may in£uence the rate of increase and peak parasitaemia, but not the timing of the ¢rst production of gametocytes.

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Transmission intensity and Plasmodium falciparum diversity on the northwestern border of Thailand.

Cited by 89 publications

References 38 publications

Selective sweep suggests transcriptional regulation may underlie Plasmodium vivax resilience to malaria control measures in Cambodia

Selective sweep suggests transcriptional regulation may underlie Plasmodium vivax resilience to malaria control measures in Cambodia

Molecular Genetic Characterization of the Merozoite Surface Protein 1 Gene of Plasmodium vivax from Reemerging Korean Isolates

Life history of a malaria parasite (Plasmodium mexicanum): independent traits and basis for variation

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