Virus quantification by real time RT-PCR RNA was extracted from infected cells using the RNeasy Mini Kit (Qiagen, Netherland). Dengue serogroup 2 virus TSV01 detection by TaqMan PCR was adapted to the ABI7900 real time instrument using previously published primers and probes [16] . Standard ABI conditions were used, incorporating primers at 900nM. Quantification was achieved by relating viral Ct value to the Ct value on a standard curve of a measured number of copies of a 750 bp section of the virus (forward: 59-AAAGATCAGTGG-CACTCGTTCC-39 and reverse: 59-GCAGGTCTAAGAAC-CATTGCCT-39), cloned into pCR2.1-TOPO (Invitrogen, USA).