title: Variation in Complexity of Infection and Transmission Stability between Neighbouring Populations of Plasmodium vivax in Southern Ethiopia.
abstract: BACKGROUND
  P. vivax is an important public health burden in Ethiopia, accounting for almost half of all malaria cases. Owing to heterogeneous transmission across the country, a stronger evidence base on local transmission dynamics is needed to optimise allocation of resources and improve malaria interventions.
  
  
  RESULTS
  In a pilot evaluation of local level P. vivax molecular surveillance in southern Ethiopia, the diversity and population structure of isolates collected between May and November 2013 were investigated. Blood samples were collected from microscopy positive P. vivax patients recruited to clinical and cross-sectional surveys from four sites: Arbaminch, Halaba, Badawacho and Hawassa. Parasite genotyping was undertaken at nine tandem repeat markers. Eight loci were successfully genotyped in 197 samples (between 36 and 59 per site). Heterogeneity was observed in parasite diversity and structure amongst the sites. Badawacho displayed evidence of unstable transmission, with clusters of identical clonal infections. Linkage disequilibrium in Badawacho was higher (IAS = 0.32, P = 0.010) than in the other populations (IAS range = 0.01-0.02) and declined markedly after adjusting for identical infections (IAS = 0.06, P = 0.010). Other than Badawacho (HE = 0.70), population diversity was equivalently high across the sites (HE = 0.83). Polyclonal infections were more frequent in Hawassa (67%) than the other populations (range: 8-44%). Despite the variable diversity, differentiation between the sites was low (FST range: 5 x 10-3-0.03).
  
  
  CONCLUSIONS
  Marked variation in parasite population structure likely reflects differing local transmission dynamics. Parasite genotyping in these heterogeneous settings has potential to provide important complementary information with which to optimise malaria control interventions.
authors.affiliation: College of Natural Sciences, Addis Ababa University, P.O. Box 52, Addis Ababa, Ethiopia; Armauer Hansen Research Institute, P.O. Box 1005, Jimma Road, Addis Ababa, Ethiopia.
authors.forename: Sisay
authors.initials: S
authors.lastname: Getachew
authors.affiliation: Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, NT 0810, Australia.
authors.forename: Sheren
authors.initials: S
authors.lastname: To
authors.affiliation: Eijkman Institute for Molecular Biology, Jl. Diponegoro 69, Jakarta Pusat 10430, Indonesia and The Ministry of Research and Technology (RISTEK), Jakarta, Indonesia; Agency for Assessment and Application of Technology, Jl. MH Thamrin 8, Jakarta 10340, Indonesia.
authors.forename: Hidayat
authors.initials: H
authors.lastname: Trimarsanto
authors.affiliation: Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, NT 0810, Australia.
authors.forename: Kamala
authors.initials: K
authors.lastname: Thriemer
authors.affiliation: Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, United Kingdom; Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, United Kingdom.
authors.forename: Taane G
authors.initials: TG
authors.lastname: Clark
authors.affiliation: College of Natural Sciences, Addis Ababa University, P.O. Box 52, Addis Ababa, Ethiopia.
authors.forename: Beyene
authors.initials: B
authors.lastname: Petros
authors.affiliation: Armauer Hansen Research Institute, P.O. Box 1005, Jimma Road, Addis Ababa, Ethiopia.
authors.forename: Abraham
authors.initials: A
authors.lastname: Aseffa
authors.affiliation: Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, NT 0810, Australia; Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom.
authors.forename: Ric N
authors.initials: RN
authors.lastname: Price
authors.affiliation: Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, NT 0810, Australia.
authors.forename: Sarah
authors.initials: S
authors.lastname: Auburn
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D003430:Cross-Sectional Studies; D005002:Ethiopia / Q000453:epidemiology; D005260:Female; D014644:Genetic Variation; D005828:Genetics, Population; D005838:Genotype; D006801:Humans; D007223:Infant; D015810:Linkage Disequilibrium; D016780:Malaria, Vivax / Q000453:epidemiology / Q000469:parasitology* / Q000635:transmission*; D008297:Male; D010966:Plasmodium vivax / Q000145:classification / Q000235:genetics*; D015995:Prevalence; D055815:Young Adult