Aerial view of San Carlos depicting the location of the three major space-time primary clusters of Plasmodium vivax haplotypes (H11, H5 and H4) and a description of all the significant clusters found during the follow up. Households mapped with GPS on Google Maps. a Number of households by cluster; b Secondary cluster; Obs = observed number of cases; Exp = expected number of cases; RR = relative risk; LLR = log likelihood ratio. Radius in meters (m). *H4 cluster from June 2009 until May 2010.