Data from the first five years of the study (August 30, 2004-June 30, 2009) were used for analysis. The first three days after onset of fever were considered the early febrile phase of illness. Day of illness at presentation was determined by the date of fever onset, which was defined as the first day of illness as reported by the parent/guardian. Variable definitions are described in Table 1 . Positive tourniquet test was examined using cut-offs of $10 petechiae/in 2 and $20 petechiae/in 2 . Platelet count was dichotomized using a cut-off of #150,000 cells/mm 3 to enable comparisons during days 1-3. Only data from days 1-8 of illness were included for analysis.