Prevalence of malaria in pregnancy in southern Laos: a cross-sectional survey.

Valérie Briand,Sommay Keomany,Paul N Newton,Nanthasane Vannavong,Mayfong Mayxay,Yom Inthavong,Jean-Yves Le Hesran,Gwladys Bertin,Keobouphaphone Chindavongsa,Nadine Fievet,Bouasy Hongvanthong,Sandrine Houzé

doi:10.1186/s12936-016-1492-2

Abstract

BackgroundThere are no data on the burden of malaria in pregnancy (MiP) in Laos, where malaria still remains prevalent in the south.MethodsTwo cross-sectional surveys were conducted in 2014 to assess the prevalence of MiP in Vapi District, Salavan Province, southern Laos: the first consisted of screening 204 pregnant women during pregnancies [mean (95 % CI) gestational age: 23 (22–25) weeks] living in 30 randomly selected villages in Vapi District; the second was conducted among 331 pregnant women, who delivered during the study period in Vapi and Toumlane District Hospitals and in Salavan Provincial Hospital. Peripheral and placental malaria was detected using rapid diagnostic tests (RDT), thick blood smears (TBS) and real-time quantitative polymerase chain reactions (RT-qPCR). Factors associated with low birth weight (LBW) and maternal anaemia were assessed.ResultsIn the villages, 12/204 women (5.9 %; 95 % CI 3.1–10.0) were infected with malaria as determined by RT-qPCR: 11 were Plasmodium vivax infections and 1 was mixed Plasmodium vivax/Plasmodium falciparum infection, among which 9 were sub-microscopic (as not detected by TBS). History of malaria during current pregnancy tended to be associated with a higher risk of MiP (aIRR 3.05; 95 % CI 0.94–9.88). At delivery, two Plasmodium falciparum sub-microscopic infections (one peripheral and one placental) were detected (4.5 %; 0.6–15.5) in Vapi District. In both surveys, all infected women stated they had slept under a bed net the night before the survey, and 86 % went to the forest for food-finding 1 week before the survey in median. The majority of infections (94 %) were asymptomatic and half of them were associated with anaemia. Overall, 24 % of women had LBW newborns. Factors associated with a higher risk of LBW were tobacco use (aIRR 2.43; 95 % CI 1.64–3.60) and pre-term delivery (aIRR 3.17; 95 % CI 2.19–4.57). Factors associated with a higher risk of maternal anaemia were no iron supplementation during pregnancy, Lao Theung ethnicity and place of living.ConclusionsThe prevalence of MiP in this population was noticeable. Most infections were asymptomatic and sub-microscopic vivax malaria, which raises the question of reliability of recommended national strategies for the screening and prevention of MiP in Laos.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-016-1492-2) contains supplementary material, which is available to authorized users.

Highlights

There are no data on the burden of malaria in pregnancy (MiP) in Laos, where malaria still remains prevalent in the south
In Laos, interventions against malaria that are recommended during pregnancy are the same as for the general population, they consist of use of insecticide-treated net (ITN) and effective treatment of symptomatic malaria [7]
We considered the following covariates: ethnicity, place of living, maternal age, gravidity, tobacco use, forest activity during the current pregnancy, gestational hypertension, use of bed net the night before admission, number of antenatal care (ANC) visits iron and folic acid supplementation during the current pregnancy, maternal anaemia at delivery, duration of pregnancy (

Summary

Introduction

There are no data on the burden of malaria in pregnancy (MiP) in Laos, where malaria still remains prevalent in the south. Few studies have reported on the prevalence and consequences of MiP in low or unstable malaria transmission areas, and in Southeast Asia, compared to high transmission areas [3]. In Laos, malaria is endemic throughout most of the country, but intensity of transmission is variable, with more intense transmission in remote and forested areas in the south [4]. Asymptomatic and sub-microscopic infections as well as symptomatic women who do not access health services are neither detected nor reported. The lack of precise information on the burden of MiP in Southeast Asia, and in Laos, has hampered effective lobbying for the inclusion of malaria preventive strategies during pregnancy [6]. In Laos, interventions against malaria that are recommended during pregnancy are the same as for the general population, they consist of use of ITNs and effective treatment of symptomatic malaria [7]

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