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Malaria Journal

, 12:339

First Online: 22 September 2013Received: 10 May 2013Accepted: 16 September 2013


BackgroundWhere malaria endemicity is low, control programmes need increasingly sensitive tools for monitoring malaria transmission intensity MTI and to better define health priorities. A cross-sectional survey was conducted in a low endemicity area of the Peruvian north-western coast to assess the MTI using both molecular and serological tools.

MethodsEpidemiological, parasitological and serological data were collected from 2,667 individuals in three settlements of Bellavista district, in May 2010. Parasite infection was detected using microscopy and polymerase chain reaction PCR. Antibodies to Plasmodium vivax merozoite surface protein-119 PvMSP119 and to Plasmodium falciparum glutamate-rich protein PfGLURP were detected by ELISA. Risk factors for exposure to malaria seropositivity were assessed by multivariate survey logistic regression models. Age-specific antibody prevalence of both P. falciparum and P. vivax were analysed using a previously published catalytic conversion model based on maximum likelihood for generating seroconversion rates SCR.

ResultsThe overall parasite prevalence by microscopy and PCR were extremely low: 0.3 and 0.9%, respectively for P. vivax, and 0 and 0.04%, respectively for P. falciparum, while seroprevalence was much higher, 13.6% for P. vivax and 9.8% for P. falciparum. Settlement, age and occupation as moto-taxi driver during previous year were significantly associated with P. falciparum exposure, while age and distance to the water drain were associated with P. vivax exposure. Likelihood ratio tests supported age seroprevalence curves with two SCR for both P. vivax and P. falciparum indicating significant changes in the MTI over time. The SCR for PfGLURP was 19-fold lower after 2002 as compared to before λ1 = 0.022 versus λ2 = 0.431, and the SCR for PvMSP119 was four-fold higher after 2006 as compared to before λ1 = 0.024 versus λ2 = 0.006.

ConclusionCombining molecular and serological tools considerably enhanced the capacity of detecting current and past exposure to malaria infections and related risks factors in this very low endemicity area. This allowed for an improved characterization of the current human reservoir of infections, largely hidden and heterogeneous, as well as providing insights into recent changes in species specific MTIs. This approach will be of key importance for evaluating and monitoring future malaria elimination strategies.

KeywordsMalaria transmission intensity Low endemicity Elimination Polymerase chain reaction Serology Peru Electronic supplementary materialThe online version of this article doi:10.1186-1475-2875-12-339 contains supplementary material, which is available to authorized users.

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Autor: Angel Rosas-Aguirre - Alejandro Llanos-Cuentas - Niko Speybroeck - Jackie Cook - Juan Contreras-Mancilla - Veronica Soto - D


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