Zika virus

Key points about Zika virus

  • The mosquito-borne Zika virus generally causes a mild flu-like illness. However, there are growing concerns about the impact Zika infection has on pregnant women and their babies.
  • The mosquitoes that are able to transmit Zika virus are not normally found in New Zealand.
  • Zika outbreaks are currently occurring in many countries,(external link) the closest to New Zealand being Samoa and Tonga.
  • While the symptoms of Zika are generally mild, pregnant women can pass the infection to their unborn child, which could lead to microcephaly and other serious brain anomalies in developing fetuses.
  • As a precaution, women who are pregnant or wanting to conceive are being advised not to travel to countries affected by Zika outbreaks.
  • There is currently no vaccination for Zika virus. 
Woman and daughter looking at ultrasound printout

Zika virus infection causes a mild illness with symptoms including:

  • low-grade fever (between 38°C and 38.9°C)
  • stillness and swelling of the joints, particularly those of hands and feet
  • muscle pain
  • headache
  • conjunctivitis (eye infection)
  • rash – could be confused with other diseases such as measles or dengue
  • post-viral weakness or lack of energy.

Little is currently known about the complications of Zika virus.

  • An unusual increase in Guillain-Barré syndrome(external link) has been observed during Zika outbreaks in French Polynesia (2013 – 2014) and Brazil (2015). 
  • In 2015, local health authorities in Brazil also observed an increase in babies born with microcephaly(external link) at the same time of an outbreak of Zika virus.
  • On 14 April 2016, the United States’ Centers for Disease Control and Prevention released a statement concluding that prenatal Zika virus infection is a cause of microcephaly and other serious brain anomalies in developing fetuses. 

More investigation and research is needed before we will be able to better understand Zika virus and its link to these conditions.

If you feel unwell after travelling to another country see your doctor. 

Your doctor will ask about your symptoms and travel history to rule out more serious diseases such as measles, rubella and dengue.

There is no specific therapy for Zika virus infection. The worst symptoms typically ease within 4–7 days.

If you are pregnant or plan to become pregnant the Ministry of Health recommends delaying travel to areas with Zika virus present. 

If you are travelling in Zika infected areas and are pregnant or plan to become pregnant, talk to your doctor first and take all precautions to avoid mosquito bites.

If you are pregnant and develop a rash, red eyes, fever or joint pain within 14 days of travel to a Zika virus infected country, please talk to your doctor and let them know your travel history.

The Ministry of Health's advice for avoiding mosquito bites:

  • Wear long-sleeved shirts and long pants.
  • Use permethrin-treated(external link) clothing and gear (such as boots, pants, socks, and tents).
  • Use insect repellents containing DEET, picaridin, oil of lemon eucalyptus (OLE), or IR3535. 
    • Insect repellents containing DEET, picaridin, and IR3535 are safe for pregnant and nursing women and children older than 2 months when used according to the product label.
    • Oil of lemon eucalyptus products should not be used on children under 3 years of age.
    • If you use both sunscreen and insect repellent, apply the sunscreen first and then the repellent.
  • Use bed nets as necessary.
  • Stay and sleep in screened-in or air-conditioned rooms.

Dr Laupepa Va'a from the Ministry of Health talks about how people travelling overseas can avoid being bitten by mosquitoes that might carry diseases such as dengue fever, malaria, yellow fever and Zika virus.

(Ministry of Health,  NZ, 2018)

Very little is known about the risk of passing the Zika virus on through sexual activity. The risk of sexual activity is thought to be low compared to that associated with mosquito bites, but due to the potentially serious implications of transmitting Zika to a pregnant woman, the Ministry of Health advises that:

  • All men who have travelled to a Zika-affected area and have a pregnant partner should abstain from sexual activity (oral, vaginal, and anal) or use condoms for the duration of the pregnancy, whether they have symptoms or not.
  • All men who have travelled to a Zika-affected area and have a partner who is at risk of becoming pregnant should abstain from sexual activity (oral, vaginal, and anal) or use condoms, whether they have symptoms or not, for at least six months after leaving a Zika-affected area.

See also: Zika and sexual transmission(external link) Centres for Disease Control, US

  • Prior to 2015, Zika virus outbreaks have occurred in areas of Africa, Southeast Asia, and the Pacific Islands.
  • In May 2015, Zika virus infections were confirmed in Brazil.
  • Currently, outbreaks are occurring in many countries, the closest to New Zealand being Samoa and Tonga.


Countries with a travel warning

The Ministry of Health recommends any women who are pregnant or plan to conceive in the near future to delay travel to countries affected with the Zika virus. See a list of countries where Zika infections are currently occurring.(external link) European Centre Disease Control

Zika virus(external link) World Health Organization
Zika virus disease – questions and answers(external link) World Health Organization
Zika virus: what we do and don’t know(external link) Ministry of Health NZ, update 27 July 2016

  1. Zika virus(external link) Ministry of Health, NZ
  2. Zika virus(external link) Centre for Disease Control and Prevention (CDC), US
  3. Zika virus(external link) European Centre for Disease Prevention and Control (ECDC)

Laboratory testing

Tests available to detect Zika virus in pregnant women

  • Reverse-transcriptase PCR (RT-PCR) can be used to detect the Zika virus during the first 1 week (inblood) to 4 weeks (in urine) of the illness.
    • This RT-PCR test is currently performed in Wellington at ESR, Auckland at Labplus, and Christchurch at Canterbury Health Laboratories
    • Expected turnaround time of 2 working days.
    • Zika virus RT-PCR can also be performed on amniotic fluid although it is not currently known how sensitive or specific this test is for congenital infection. The likelihood of an infected fetus developing a fetal abnormality is not known at this time.
  • Serology is less reliable due to potential cross-reaction with antibodies against other similar viruses (including dengue). 
  • Source: Laboratory testing(external link) Ministry of Health, NZ

Guidance for health professionals 

Information about zika virus and pregnancy for health professionals(external link) Ministry of Health, NZ
Factsheet for health professionals(external link) European Centre for Disease Prevention and Control (EDC)
Information for clinicians(external link) Centre for Disease Control and Prevention (CDC), US

Presentation by Dr Emma Parry 2017

(Goodfellow Symposium, 2017)

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