MOCID staffs will visit hospital and bring samples back to MOCID. C6/36 cells will be inoculated with 100 micro L of serum for virus isolation. One hundred and forty micro L serum will be used for RNA extraction followed by RT-PCR for the detection of DV and CHIKV. The results of RT-PCR will be returned to the hospital. After virus isolation, viral RNA genome will be extracted, cDNA will be synthesized, and the nucleotide sequences of viral genome will be determined.