title: Prevalence of malaria in pregnancy in southern Laos: a cross-sectional survey.
abstract: There are no data on the burden of malaria in pregnancy (MiP) in Laos, where malaria still remains prevalent in the south.
  
  
  
  Two 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.
  
  
  
  In 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.
  
  
  
  The 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.
authors: Faculté de Pharmacie, Institut de Recherche pour le Développement (IRD), Mère et enfant face aux infections tropicales (UMR216), 4 avenue de l'Observatoire, 75006, Paris, France. valerie.briand@ird.fr.|COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, Paris, France. valerie.briand@ird.fr.
authors: Valérie
authors: V
authors: Briand
authors: Faculté de Pharmacie, Institut de Recherche pour le Développement (IRD), Mère et enfant face aux infections tropicales (UMR216), 4 avenue de l'Observatoire, 75006, Paris, France.|COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, Paris, France.
authors: Jean-Yves
authors: JY
authors: Le Hesran
authors: Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Vientiane, Lao People's Democratic Republic.|Faculty of Postgraduate Studies, University of Health Sciences, Vientiane, Lao People's Democratic Republic.|Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
authors: Mayfong
authors: M
authors: Mayxay
authors: Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Vientiane, Lao People's Democratic Republic.|Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
authors: Paul N
authors: PN
authors: Newton
authors: Faculté de Pharmacie, Institut de Recherche pour le Développement (IRD), Mère et enfant face aux infections tropicales (UMR216), 4 avenue de l'Observatoire, 75006, Paris, France.|COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, Paris, France.
authors: Gwladys
authors: G
authors: Bertin
authors: Faculté de Pharmacie, Institut de Recherche pour le Développement (IRD), Mère et enfant face aux infections tropicales (UMR216), 4 avenue de l'Observatoire, 75006, Paris, France.|COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, Paris, France.|Laboratoire de Parasitologie, CNR du Paludisme, AP-HP, Hôpital Bichat, Paris, France.
authors: Sandrine
authors: S
authors: Houzé
authors: Salavan Provincial Hospital, Salavan, Salavan Province, Lao People's Democratic Republic.
authors: Sommay
authors: S
authors: Keomany
authors: Vapi District Hospital, Vapi, Salavan Province, Lao People's Democratic Republic.
authors: Yom
authors: Y
authors: Inthavong
authors: Champasack Provincial Health Office, Champasack, Champasack Province, Lao People's Democratic Republic.
authors: Nanthasane
authors: N
authors: Vannavong
authors: Center of Malariology, Parasitology and Entomology, Vientiane, Lao People's Democratic Republic.
authors: Keobouphaphone
authors: K
authors: Chindavongsa
authors: Center of Malariology, Parasitology and Entomology, Vientiane, Lao People's Democratic Republic.
authors: Bouasy
authors: B
authors: Hongvanthong
authors: Faculté de Pharmacie, Institut de Recherche pour le Développement (IRD), Mère et enfant face aux infections tropicales (UMR216), 4 avenue de l'Observatoire, 75006, Paris, France.|COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, Paris, France.
authors: Nadine
authors: N
authors: Fievet
mesh_terms: D000328:Adult; D002846:Chromatography, Affinity; D003430:Cross-Sectional Studies; D003955:Diagnostic Tests, Routine; D005260:Female; D006801:Humans; D007812:Laos / Q000453:epidemiology; D016778:Malaria, Falciparum / Q000453:epidemiology*; D016780:Malaria, Vivax / Q000453:epidemiology*; D008853:Microscopy; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology*; D015995:Prevalence; D060888:Real-Time Polymerase Chain Reaction; D055815:Young Adult
keywords: Epidemiology; Laos; Low birth weight; Malaria; Molecular biology; Pregnancy