Gold standard investigation for Zika Virus:
**Core Concept**
The diagnosis of Zika virus infection requires a sensitive and specific laboratory test, as the clinical presentation can be similar to other arboviral infections. **Viral RNA detection** is a crucial step in confirming the presence of Zika virus.
**Why the Correct Answer is Right**
The gold standard investigation for Zika virus is **RT-PCR (Reverse Transcription Polymerase Chain Reaction)**, which involves the amplification of viral RNA to detect the presence of the virus. This technique is highly sensitive and specific, allowing for early diagnosis and confirmation of Zika virus infection. RT-PCR targets specific regions of the viral genome, such as the NS1 gene, to accurately detect the virus.
**Why Each Wrong Option is Incorrect**
**Option A:** ELISA (Enzyme-Linked Immunosorbent Assay) is a serological test that detects antibodies against Zika virus, but it may not be accurate in the early stages of infection.
**Option B:** Blood culture is not a reliable method for diagnosing Zika virus infection, as the virus is not typically cultured from blood.
**Option C:** Serology-based tests, such as indirect immunofluorescence assay (IFA), may not be as sensitive as RT-PCR in detecting Zika virus infection.
**Clinical Pearl / High-Yield Fact**
RT-PCR is a highly sensitive and specific test for diagnosing Zika virus infection, especially in the early stages of illness.
**Correct Answer:** C.