further tested with Zika virus-specific real-time quantitative RT-PCR (2) by using the QuantiTect Probe RT-PCR Kit (QIAGEN, Valencia, CA, USA) with amplification in the iCycler iQ5 (Bio-Rad, Hercules, CA, USA), following the manufacturer's instructions.Viral titers of JMB-185, as determined by real-time quantitative RT-PCR, were 4.25 × 10 3 PFU, 5.07 × 10 7 PFU, and 7.33 × 10 6 PFU for the clinical sample, first passage, and second passage, respectively.The isolation and characterization of Zika virus from a resident with no travel history confirm that the virus is circulating in Indonesia and that, by mimicking mild dengue infection, this infection is likely contributing to the large number of undiagnosed cases of acute febrile illness.Although reported human cases of Zika virus infection have been rare in Southeast Asia (1), confusion with dengue and difficulty in obtaining a laboratory diagnosis are likely causing its incidence to be underestimated.Surveillance must be implemented to evaluate and monitor the distribution of Zika virus and the potential public health problems it may cause in Indonesia.