Dengue Outbreak in Martin County, Florida in 2013

Following a 2013 outbreak of dengue serotype 1 in Martin County, Florida, plasma samples from individuals with suspected dengue illness were tested for serotypespecific neutralization of dengue viruses 1-4. Titers and seroprevalence in these suspected cases from Florida were compared to those from (1) healthy donors from the U.S. and (2) dengue-suspected and dengue-confirmed samples collected from dengue-endemic regions during outbreaks in Puerto Rico in 2010 and Brazil in 2014. By dengue plaque reduction neutralization titer assays, we confirmed that four of the nine suspected individuals from Martin County Florida had been exposed to dengue virus serotype 1, and that these were primary dengue viral infections. Furthermore, primary and secondary dengue viral infections were observed in the Brazilian cohort, and a high incidence of secondary infections was observed in the Puerto Rican samples. Routine serotype-specific surveillance may be needed to continue monitoring establishment of dengue serotype 1 and