title: Childhood Diarrhea Exhibits Spatiotemporal Variation in Northwest Ethiopia: A SaTScan Spatial Statistical Analysis.
abstract: BACKGROUND
  Childhood diarrhea continues to be a public health problem in developing countries, including Ethiopia. Detecting clusters and trends of childhood diarrhea is important to designing effective interventions. Therefore, this study aimed to investigate spatiotemporal clustering and seasonal variability of childhood diarrhea in northwest Ethiopia.
  
  
  METHODS
  Retrospective record review of childhood diarrhea was conducted using quarterly reported data to the district health office for the seven years period beginning July 1, 2007. Thirty three districts were included and geo-coded in this study. Spatial, temporal and space-time scan spatial statistics were employed to identify clusters of childhood diarrhea. Smoothing using a moving average was applied to visualize the trends and seasonal pattern of childhood diarrhea. Statistical analyses were performed using Excel® and SaTScan programs. The maps were plotted using ArcGIS 10.0.
  
  
  RESULTS
  Childhood diarrhea in northwest Ethiopia exhibits statistical evidence of spatial, temporal, and spatiotemporal clustering, with seasonal patterns and decreasing temporal trends observed in the study area. A most likely purely spatial cluster was found in the East Gojjam administrative zone of Gozamin district (LLR = 7123.89, p <0.001). The most likely spatiotemporal cluster was detected in all districts of East Gojjam zone and a few districts of the West Gojjam zone (LLR = 24929.90, p<0.001), appearing from July 1, 2009 to June 30, 2011. One high risk period from July 1, 2008 to June 30, 2010 (LLR = 9655.86, p = 0.001) was observed in all districts. Peak childhood diarrhea cases showed a seasonal trend, occurring more frequently from January to March and April to June.
  
  
  CONCLUSIONS
  Childhood diarrhea did not occur at random. It has spatiotemporal variation and seasonal patterns with a decreasing temporal trend. Accounting for the spatiotemporal variation identified in the study areas is advised for the prevention and control of diarrhea.
authors.affiliation: Ethiopian Institute of Water Resources, Addis Ababa University, Addis Ababa, Ethiopia.
authors.forename: Muluken
authors.initials: M
authors.lastname: Azage
authors.affiliation: School of Public Health, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
authors.forename: Abera
authors.initials: A
authors.lastname: Kumie
authors.affiliation: School of Public Health, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
authors.forename: Alemayehu
authors.initials: A
authors.lastname: Worku
authors.affiliation: Department of Civil and Environmental Engineering, School of Engineering, University of Connecticut, Storrs, CT 06269, United States of America.
authors.forename: Amvrossios C
authors.initials: AC
authors.lastname: Bagtzoglou
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003967:Diarrhea / Q000453:epidemiology*; D005002:Ethiopia / Q000453:epidemiology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008954:Models, Biological; D012189:Retrospective Studies