Gametocyte dynamics and the role of drugs in reducing the transmission potential of Plasmodium vivax - PubMed (original) (raw)

Meta-Analysis

. 2013 Sep 1;208(5):801-12.

doi: 10.1093/infdis/jit261. Epub 2013 Jun 12.

Julie A Simpson, Aung Pyae Phyo, Hadjar Siswantoro, Armedy R Hasugian, Enny Kenangalem, Jeanne Rini Poespoprodjo, Pratap Singhasivanon, Nicholas M Anstey, Nicholas J White, Emiliana Tjitra, Francois Nosten, Ric N Price

Affiliations

Meta-Analysis

Gametocyte dynamics and the role of drugs in reducing the transmission potential of Plasmodium vivax

Nicholas M Douglas et al. J Infect Dis. 2013.

Abstract

Background: Designing interventions that will reduce transmission of vivax malaria requires knowledge of Plasmodium vivax gametocyte dynamics.

Methods: We analyzed data from a randomized controlled trial in northwestern Thailand and 2 trials in Papua, Indonesia, to identify and compare risk factors for vivax gametocytemia at enrollment and following treatment.

Results: A total of 492 patients with P. vivax infections from Thailand and 476 patients (162 with concurrent falciparum parasitemia) from Indonesia were evaluable. Also, 84.3% (415/492) and 66.6% (209/314) of patients with monoinfection were gametocytemic at enrollment, respectively. The ratio of gametocytemia to asexual parasitemia did not differ between acute and recurrent infections (P = .48 in Thailand, P = .08 in Indonesia). High asexual parasitemia was associated with an increased risk of gametocytemia during follow-up in both locations. In Thailand, the cumulative incidence of gametocytemia between day 7 and day 42 following dihydroartemisinin + piperaquine (DHA + PIP) was 6.92% vs 29.1% following chloroquine (P < .001). In Indonesia, the incidence of gametocytemia was 33.6% following artesunate + amodiaquine (AS + AQ), 7.42% following artemether + lumefantrine, and 6.80% following DHA + PIP (P < .001 for DHA + PIP vs AS + AQ).

Conclusions: P. vivax gametocyte carriage mirrors asexual-stage infection. Prevention of relapses, particularly in those with high asexual parasitemia, is likely the most important strategy for interrupting P. vivax transmission.

Keywords: Plasmodium vivax; antimalarial drugs; epidemiology; gametocytes; transmission.

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Figures

Figure 1.

Figure 1.

Frequency distribution of loge gametocyte density for those with Plasmodium vivax monoinfections on presentation for treatment and at the time of recurrence.

Figure 2.

Figure 2.

Proportion of individuals examined with sexual and/or asexual forms of Plasmodium vivax from presentation through to end of follow-up in Thailand and Indonesia (excludes patients with mixed infection on presentation in Indonesia). Abbreviations: AM + LUM, artemether + lumefantrine; AS + AQ, artesunate + amodiaquine; CQ, chloroquine; DHA + PIP, monotherapy dihydroartemisinin + piperaquine.

Figure 3.

Figure 3.

Correlation between the loge density of asexual and sexual stages of Plasmodium vivax at presentation for treatment and at the time of recurrence after treatment (analyses limited to those with P. vivax monoinfections at enrollment).

References

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