Special Precautions/Comments:

N.B. Please provide a detailed travel history. (Please also provide travel history of sexual partner if sexual transmission is suspected).

Interferences:  Zika virus IgM is frequently not detectable in individuals who have previously had previous flavivirus infection (including dengue virus). These same viruses can cause cross-reactivity producing a positive Zika virus IgG result.

Method: Enzyme immunoassay (EIA) for the determination of Zika Virus IgG and IgM antibody levels. Real-time polymerase chain reaction (RT-PCR) for the detection of Zika Virus DNA. Calibration: – EQA scheme: – IQC: –

Interpretation: Results will be reported as DETECTED (positive) or NOT detected (negative). A negative PCR result does not exclude previous infection. Clinical comments will be provided based on patient history.

If Zika virus antibodies are not detected in a serum sample collected at least 2 weeks after the onset of an acute viral illness featuring fever, rash, arthralgia or conjunctivitis in a pregnant woman, appropriate investigations for alternative causes including parvovirus, rubella, CMV, dengue and chikungunya infections must be carried out, if not already done so.

If Zika virus antibodies are not detected in a serum sample collected 4 or more weeks* after the last possible travel-associated or sexual exposure, then recent Zika virus infection is highly unlikely. Therefore, pregnant women with negative antibody results for such samples do not require further extra fetal ultrasound follow-up, unless there are additional concerns.

For further information contact UKHSA Porton Down, Rare and imported pathogens laboratory (RIPL).

Additional Information:

Background information: Zika virus is non-endemic to the UK and is caused by a viral infection spread by Aedes mosquitoes. High risk areas include regions of Africa, Asia, the Pacific Islands, Central and South America and the Caribbean.

Most Zika virus infections remain asymptomatic and severe illness is uncommon. However, Zika virus is a known cause of congenital birth defects, such as microcephaly, and has been linked to neurological problems, such as Guillain-Barré syndrome.

Zika virus should be considered for patients who have recently returned from high risk areas and have presented with symptoms that began either whist abroad or within 2 weeks of returning to the UK. Symptoms include a rash, itching or pruritus, fever, headache, arthralgia or arthritis, myalgia, conjunctivitis, lower back pain, retro-orbital pain. Zika virus may also be sexually transmitted. If the patient is presenting with typical Zika-like symptoms consider sexual transmission if their sexual partner has visited a high risk country within the last 3 months.