Seasonality of plate agglutination tests results and rainfall. Grey bars show the number of test positives. A line shows monthly rainfall in Namulonge, Uganda. Monthly rainfall data were presented until December 2005 and after then the average monthly rainfalls between 1999 and 2005 were presented, because the published data are not available in 2006. There were periods clustered for months which plate agglutination tests could not be performed due to lack of the kits.