Determining the etiology of human diseases with symptoms that overlap with dengue-like illness is important for understanding the full spectrum of emerging or previously uncharacterized pathogens in tropical populations. In this study, 10% of acute serum samples negative for dengue virus from cases of pediatric dengue-like illness were positive for HHV-6. Primary HHV-6 infection causes undifferentiated febrile illness and exanthem subitum (roseola infantum or sixth disease), an acute illness with high fever and rash that typically resolves in three to seven days [49] . Exanthem subitum is a common disease of infants worldwide, and HHV-6 infection most frequently occurs between 6 and 12 months of age [50] , with seropositivity estimates of .95% in adult populations in developed countries [51] . The HHV-6 positive patients in this study were between 7-12 months old, and presented with fever and rash (Table S3) . We detected multiple kilobases of HHV-6 sequence in each positive sample, with sequence deriving from multiple viral genomic regions (Figure 2 ).