title: Spatial heterogeneity of malaria in Ghana: a cross-sectional study on the association between urbanicity and the acquisition of immunity.
abstract: BACKGROUND
  Malaria incidence has declined considerably over the last decade. This is partly due to a scale-up of control measures but is also attributed to increasing urbanization. This study aimed to analyse the association between malaria and urbanization and the effect of urbanicity on the acquisition of semi-immunity.
  
  
  METHODS
  In 2012, children with fever presenting to St Michael's Hospital Pramso/Ghana were recruited. The malaria-positive-fraction (MPF) of fever cases was calculated on community-level to approximate the malaria risk. The mean age of malaria cases was calculated for each community to estimate the acquisition of semi-immunity. The level of urbanicity for the communities was calculated and associations between MPF, urbanicity and immunity were modelled using linear regression.
  
  
  RESULTS
  Twenty-six villages were included into the study with a mean MPF of 35 %. A linear decrease of 5 % (95 % CI: 4-6 %) in MPF with every ten-point increase in urbanicity was identified. The mean age of malaria patients increased by 2.9 months (95 % CI: 1.0-4.8) with every ten-point increase in urbanicity.
  
  
  CONCLUSIONS
  The results confirm an association between an increase in urbanicity and declining malaria risk and demonstrate that the acquisition of semi-immunity is heterogeneous on a micro-epidemiological scale and is associated with urbanicity.
authors: Research Group Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany. clemensfrank@gmx.de.|Institute of Microbiology and Hygiene, Charité-University Medicine, Berlin, Germany. clemensfrank@gmx.de.
authors: Clemens
authors: C
authors: Frank
authors: Research Group Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany. krumkamp@bnitm.de.|German Centre for Infection Research (DZIF), Partner Site Hamburg-Borstel-Lübeck, Hamburg, Germany. krumkamp@bnitm.de.
authors: Ralf
authors: R
authors: Krumkamp
authors: Kumasi Centre for Collaborative Research in Tropical Medicine, College of Health Sciences, KNUST, Kumasi, Ghana. nimakosarpong@yahoo.com.
authors: Nimako
authors: N
authors: Sarpong
authors: Research Group Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany. p.sothmann@uke.de.|Division of Tropical Medicine, 1st Department of Medicine, University Medical Centre Hamburg Eppendorf, Hamburg, Germany. p.sothmann@uke.de.
authors: Peter
authors: P
authors: Sothmann
authors: School of Public Health, University of Ghana, Accra, Ghana. jfobil@gmail.com.
authors: Julius N
authors: JN
authors: Fobil
authors: Kumasi Centre for Collaborative Research in Tropical Medicine, College of Health Sciences, KNUST, Kumasi, Ghana. geoffreyf4@yahoo.com.
authors: Geoffrey
authors: G
authors: Foli
authors: Research Group Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany. anna.jaeger@bnitm.de.
authors: Anna
authors: A
authors: Jaeger
authors: Research Group Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany. Lutz.Ehlkes@gmail.com.
authors: Lutz
authors: L
authors: Ehlkes
authors: Kumasi Centre for Collaborative Research in Tropical Medicine, College of Health Sciences, KNUST, Kumasi, Ghana. owusudabo@kccr.de.
authors: Ellis
authors: E
authors: Owusu-Dabo
authors: School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. yasax@hotmail.co.uk.
authors: Yaw
authors: Y
authors: Adu-Sarkodie
authors: International Vaccine Institute, Seoul, Korea. fmarks@IVI.INT.
authors: Florian
authors: F
authors: Marks
authors: Institute of Microbiology and Hygiene, Charité-University Medicine, Berlin, Germany. ralf.schumann@charite.de.
authors: Ralf R
authors: RR
authors: Schumann
authors: Research Group Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany. may@bnitm.de.|German Centre for Infection Research (DZIF), Partner Site Hamburg-Borstel-Lübeck, Hamburg, Germany. may@bnitm.de.
authors: Jürgen
authors: J
authors: May
authors: Research Group Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany. b.kreuels@uke.de.|German Centre for Infection Research (DZIF), Partner Site Hamburg-Borstel-Lübeck, Hamburg, Germany. b.kreuels@uke.de.|Division of Tropical Medicine, 1st Department of Medicine, University Medical Centre Hamburg Eppendorf, Hamburg, Germany. b.kreuels@uke.de.
authors: Benno
authors: B
authors: Kreuels
mesh_terms: D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D005869:Ghana / Q000453:epidemiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008288:Malaria / Q000453:epidemiology*; D008297:Male; D014507:Urbanization