title: Spatial clustering and risk factors of malaria infections in Bata district, Equatorial Guinea.
abstract: The transmission of malaria is intense in the majority of the countries of sub-Saharan Africa, particularly in those that are located along the Equatorial strip. The present study aimed to describe the current distribution of malaria prevalence among children and its environment-related factors as well as to detect malaria spatial clusters in the district of Bata, in Equatorial Guinea.
  
  
  
  From June to August 2013 a representative cross-sectional survey using a multistage, stratified, cluster-selected sample was carried out of children in urban and rural areas of Bata District. All children were tested for malaria using rapid diagnostic tests (RDTs). Results were linked to each household by global position system data. Two cluster analysis methods were used: hot spot analysis using the Getis-Ord Gi statistic, and the SaTScan™ spatial statistic estimates, based on the assumption of a Poisson distribution to detect spatial clusters. In addition, univariate associations and Poisson regression model were used to explore the association between malaria prevalence at household level with different environmental factors.
  
  
  
  A total of 1416 children aged 2 months to 15 years living in 417 households were included in this study. Malaria prevalence by RDTs was 47.53%, being highest in the age group 6-15 years (63.24%, p < 0.001). Those children living in rural areas were there malaria risk is greater (65.81%) (p < 0.001). Malaria prevalence was higher in those houses located <1 km from a river and <3 km to a forest (IRR: 1.31; 95% CI 1.13-1.51 and IRR: 1.44; 95% CI 1.25-1.66, respectively). Poisson regression analysis also showed a decrease in malaria prevalence with altitude (IRR: 0.73; 95% CI 0.62-0.86). A significant cluster inland of the district, in rural areas has been found.
  
  
  
  This study reveals a high prevalence of RDT-based malaria among children in Bata district. Those households situated in inland rural areas, near to a river, a green area and/or at low altitude were a risk factor for malaria. Spatial tools can help policy makers to promote new recommendations for malaria control.
authors.affiliation: CIBERESP, National Centre of Epidemiology, Carlos III Institute of Health (ISCIII), Madrid, Spain. dgomez@externos.isciii.es.
authors.forename: Diana
authors.initials: D
authors.lastname: Gómez-Barroso
authors.affiliation: RICET, National Center of Tropical Medicine, Carlos III Institute of Health (ISCIII), Madrid, Spain.
authors.forename: Emely
authors.initials: E
authors.lastname: García-Carrasco
authors.affiliation: RICET, National Center of Tropical Medicine, Carlos III Institute of Health (ISCIII), Madrid, Spain.
authors.forename: Zaida
authors.initials: Z
authors.lastname: Herrador
authors.affiliation: Reference Centre for Endemic Control of Equatorial Guinea (CRCE), Malabo, Equatorial Guinea.
authors.forename: Policarpo
authors.initials: P
authors.lastname: Ncogo
authors.affiliation: RICET, National Center of Tropical Medicine, Carlos III Institute of Health (ISCIII), Madrid, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Romay-Barja
authors.affiliation: Ministry of Health and Social Welfare, Malabo, Equatorial Guinea.
authors.forename: Martín Eka
authors.initials: ME
authors.lastname: Ondo Mangue
authors.affiliation: Ministry of Health and Social Welfare, Malabo, Equatorial Guinea.
authors.forename: Gloria
authors.initials: G
authors.lastname: Nseng
authors.affiliation: Ministry of Health and Social Welfare, Malabo, Equatorial Guinea.
authors.forename: Matilde
authors.initials: M
authors.lastname: Riloha
authors.affiliation: University Institute for Tropical Diseases and Public Health of Canarias, Tenerife, Spain.
authors.forename: Maria Angeles
authors.initials: MA
authors.lastname: Santana
authors.affiliation: University Institute for Tropical Diseases and Public Health of Canarias, Tenerife, Spain.
authors.forename: Basilio
authors.initials: B
authors.lastname: Valladares
authors.affiliation: RICET, National Center of Tropical Medicine, Carlos III Institute of Health (ISCIII), Madrid, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Aparicio
authors.affiliation: RICET, National Center of Tropical Medicine, Carlos III Institute of Health (ISCIII), Madrid, Spain.
authors.forename: Agustín
authors.initials: A
authors.lastname: Benito
mesh_terms: D000293:Adolescent; D000818:Animals; D002648:Child; D002675:Child, Preschool; D002846:Chromatography, Affinity; D016000:Cluster Analysis; D003430:Cross-Sectional Studies; D004777:Environment; D016703:Equatorial Guinea / Q000453:epidemiology; D005260:Female; D006801:Humans; D007223:Infant; D008288:Malaria / Q000453:epidemiology*; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D012424:Rural Population; D062206:Spatial Analysis; D019371:Topography, Medical; D014505:Urban Population
keywords: Children; Equatorial Guinea; Malaria; Rapid diagnostic tests; Spatial