The primary diagnosis of ZIKV infection is based on the patient's typical clinical features, places and dates of travel and activities. During the first week after onset of symptoms, laboratory diagnosis can be performed by using reverse-transcriptase polymerase chain reaction (RT-PCR) on serum or plasma to detect virus, viral nucleic acid,
or virus-specific immunoglobulin M and neutralizing antibodies. During the acute illness period of ZIKV infection in patients, symptoms such as fever, rash, conjunctivitis, and serological testing can confirm the presence of ZIKV virus.