title: Malaria epidemiology in central Myanmar: identification of a multi-species asymptomatic reservoir of infection.
abstract: BACKGROUND
  The spread of artemisinin-resistant Plasmodium falciparum is a global health concern. Myanmar stands at the frontier of artemisinin-resistant P. falciparum. Myanmar also has the highest reported malaria burden in Southeast Asia; it is integral in the World Health Organization's plan to eliminate malaria in Southeast Asia, yet few epidemiological data exist for the general population in Myanmar.
  
  
  METHODS
  This cross-sectional, probability household survey was conducted in Phyu township, Bago Region (central Myanmar), during the wet season of 2013. Interviewers collected clinical and behavioural data, recorded tympanic temperature and obtained dried blood spots for malaria PCR and serology. Plasmodium falciparum positive samples were tested for genetic mutations in the K13 region that may confer artemisinin resistance. Estimated type-specific malaria PCR prevalence and seroprevalence were calculated, with regression analysis to identify risk factors for seropositivity to P. falciparum. Data were weighted to account for unequal selection probabilities.
  
  
  RESULTS
  1638 participants were sampled (500 households). Weighted PCR prevalence was low (n = 41, 2.5%) and most cases were afebrile (93%). Plasmodium falciparum was the most common species (n = 19. 1.1%) and five (26%) P. falciparum samples harboured K13 mutations. Plasmodium knowlesi was detected in 1.0% (n = 16) and Plasmodium vivax was detected in 0.4% (n = 7). Seroprevalence was 9.4% for P. falciparum and 3.1% for P. vivax. Seroconversion to P. falciparum was 0.003/year in the whole population, but 16-fold higher in men over 23 years old (LR test p = 0.016).
  
  
  CONCLUSIONS
  This is the first population-based seroprevalence study from central Myanmar. Low overall prevalence was discovered. However, these data suggest endemic transmission continues, probably associated with behavioural risk factors amongst working-age men. Genetic mutations associated with P. falciparum artemisinin resistance, the presence of P. knowlesi and discrete demographic risk groups present opportunities and challenges for malaria control. Responses targeted to working-age men, capable of detecting sub-clinical infections, and considering all species will facilitate malaria elimination in this setting.
authors.affiliation: Research Department of Infection and Population Health, University College London, London, WC1E 6JB, UK.
authors.forename: Isaac
authors.identifier: http://orcid.org/0000-0003-1322-1331
authors.initials: I
authors.lastname: Ghinai
authors.affiliation: Malaria Centre, London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Jackie
authors.initials: J
authors.lastname: Cook
authors.affiliation: Institute for Global Health, University College London, London, UK.
authors.forename: Teddy Tun Win
authors.initials: TT
authors.lastname: Hla
authors.affiliation: Research Department of Infection and Population Health, University College London, London, WC1E 6JB, UK.
authors.forename: Hein Myat Thu
authors.initials: HM
authors.lastname: Htet
authors.affiliation: Malaria Centre, London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Tom
authors.initials: T
authors.lastname: Hall
authors.affiliation: Department of Immunology & Infection, London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Inke Nd
authors.initials: IN
authors.lastname: Lubis
authors.affiliation: Haematology, Severn Deanery, Bristol, UK.
authors.forename: Rosanna
authors.initials: R
authors.lastname: Ghinai
authors.affiliation: Institute for Global Health, University College London, London, UK.
authors.forename: Therese
authors.initials: T
authors.lastname: Hesketh
authors.affiliation: University of Medicine (2), Yangon, Myanmar.
authors.forename: Ye
authors.initials: Y
authors.lastname: Naung
authors.affiliation: University of Medicine (2), Yangon, Myanmar.
authors.forename: Mya Mya
authors.initials: MM
authors.lastname: Lwin
authors.affiliation: University of Medicine (2), Yangon, Myanmar.
authors.forename: Tint Swe
authors.initials: TS
authors.lastname: Latt
authors.affiliation: Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: David L
authors.initials: DL
authors.lastname: Heymann
authors.affiliation: Department of Immunology & Infection, London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Sutherland
authors.affiliation: Malaria Centre, London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Drakeley
authors.affiliation: Research Department of Infection and Population Health, University College London, London, WC1E 6JB, UK. nigel.field@ucl.ac.uk.
authors.forename: Nigel
authors.initials: N
authors.lastname: Field
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D058070:Asymptomatic Diseases / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005191:Family Characteristics; D005260:Female; D006801:Humans; D007223:Infant; D008288:Malaria / Q000453:epidemiology* / Q000469:parasitology; D008297:Male; D008875:Middle Aged; D002052:Myanmar / Q000453:epidemiology; D010961:Plasmodium / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D010963:Plasmodium falciparum / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D016790:Plasmodium knowlesi / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D010966:Plasmodium vivax / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction; D016036:Seroepidemiologic Studies; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: Artemisinin; Elimination; Malaria; Myanmar; Prevalence; Resistance; Risk factors; Serology; Transmission