Zika virus is mainly transmitted by mosquitoes and may be present in any country that has the mosquitoes able to spread it. To date, the virus has been found in parts of Africa, southern Asia, the Pacific Islands, and the Americas.
Rare instances of sexual transmission (mainly male to sex partner) have also been documented.
There are concerns that pregnant women who become infected with Zika can transmit the disease to their unborn babies, with potentially serious consequences. Reports from several countries, including Brazil, indicate an increase in severe birth defects (microcephaly in particular) in babies whose mothers were infected while pregnant.
There are also concerns that Zika sometimes leads to Guillain-Barré syndrome, a serious neurological disorder caused by the immune system reacting to Zika infection.
Based on research to date, there is scientific consensus that Zika virus is a cause of microcephaly and other severe fetal brain abnormalities, as well as Guillain-Barré syndrome.
There is ongoing research about how Zika can affect infected people.
New Zealand and world health authorities are continuing to monitor the spread of Zika virus.
Cases in New Zealand
Between 1 January 2016 and 27 July 2016, a total of 90 confirmed cases of Zika virus have been reported in New Zealand. Visit the ESR website for weekly updates.
All cases of Zika reported in New Zealand have been connected to recent travel to countries where an outbreak was occurring.
The rise in numbers of cases reported in New Zealand at the beginning of this year was not unexpected. It corresponded with a rise in the number of countries reporting active transmission of the virus, including several countries in the Pacific, and with the holiday season with more people returning from overseas travel.
Cases reported in New Zealand peaked in February, and have been consistently low since then. We anticipate that numbers will likely remain low over winter. However, it is important for anyone travelling overseas to be aware of mosquito-borne illnesses which may be present, and take precautions to prevent being bitten.
Only around 1 in 5 people who are infected with Zika experience any symptoms. The virus causes mild symptoms that can last from 4–7 days. If someone does get symptoms, they are likely to occur within a few days to a week after being infected, but they may take up to 12 days to appear.
For those who do experience symptoms, they are likely to be mild. They can include:
- low-grade fever
- joint pain, especially in the small joints of the hands and feet, with possible swelling
- muscle pain
- red eyes
Zika infection may cause a rash that could be confused with other serious diseases such as measles or dengue, so it's important to check with a health care professional to rule out these diseases.
There are no specific treatments for Zika virus. Symptoms will typically clear up after 4–7 days.
Use paracetamol for pain and fever if needed. Until a health care professional can rule out dengue, do not take aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, as there is a risk of bleeding.
Anyone with symptoms should get plenty of rest and fluids.
If you're pregnant or trying to get pregnant, and you've recently travelled to an area with Zika, we recommend that you speak with your health care provider or lead maternity carer, even if you do not feel sick. It is especially important to see a health care provider if you develop a fever, rash, joint pain, or red eyes during your trip or within 2 weeks after travelling to a country where Zika has been reported.
Call Healthline 0800 611 116 if you are unsure what to do.
There is no vaccine for Zika virus. Because Zika virus is spread by mosquitoes, the best way to prevent infection is to avoid being bitten.
We recommend that people who travel to any Pacific Island country should protect themselves against mosquito bites.
If you are travelling outside the Pacific area, you should check the ECDC website for the most up-to-date list of countries with confirmed Zika virus transmissions.
If you are pregnant or planning to become pregnant in the near term
Anyone who is pregnant or plans to become pregnant in the near term should defer travel to a Zika-affected area. We recommend that women travelling in Zika-affected areas protect themselves against mosquito bites and, if needed, use an appropriate contraception to prevent pregnancy.
Women returning from Zika-affected areas should avoid getting pregnant for 8 weeks after leaving the affected country.
Sexual transmission of Zika
Though Zika virus is mainly transmitted by mosquitoes, there is scientific evidence to suggest the virus can be sexually transmitted. The best way to reduce the possibility of sexual transmission of the virus, or the possibility of becoming pregnant while infected with Zika virus, is to avoid sex or use condoms.
All men who have travelled to a Zika-affected area should avoid sex or use condoms, even if you do not have symptoms.
- If your partner is pregnant, you should abstain from sexual activity (oral, vaginal, or anal) or use condoms for the duration of the pregnancy.
- If you have a partner who is at risk of becoming pregnant, you should abstain from sexual activity (oral, vaginal, or anal), or use condoms, for at least six months after leaving a Zika-affected area.
There is only limited evidence available at this time about how long men should abstain from sex or use condoms. Initial research has found Zika virus present in semen at least 2 months after infection develops. However, how infectious the virus remains and how much longer it can possibly stay in the semen is not known. Until more information on the duration of sexual transmission becomes available, men should use condoms or abstain from sexual activity (oral, vaginal, or anal) for at least 6 months after leaving a Zika-affected area.
It's important that you abstain from sexual activity (oral, vaginal, or anal) or use condoms even if you are not showing symptoms. Only 1 in 5 people who get the Zika infection will show symptoms, so it's possible to have the infection and not know it.
Advice about avoiding sexual transmission of Zika virus can also be found on the following websites:
In New Zealand, we will continue to update our advice as further information becomes available.
Rio 2016 Olympic and Paralympic Games
The Ministry of Health has provided updated advice as required to a range of groups, including the New Zealand Olympic Committee.
People travelling to Rio for the Olympics who are concerned about Zika should talk to their GP.
The Ministry of Health will continue to review New Zealand guidance as further information becomes available.
Protect yourself from mosquitoes
Everyone who is travelling to an affected country should protect themselves from mosquitoes.
- Use insect repellents and check the label to make sure they contain DEET, picaridin, oil of lemon eucalyptus (OLE), or IR3535. Always use as directed.
- Insect repellents containing DEET, picaridin, and IR3535 are safe for pregnant and breastfeeding 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.
- Wear long-sleeved shirts and long pants. You can use insect repellent to treat your clothing, as directed.
- Use clothing and gear (such as boots, pants, socks, and tents) that has been treated with the insecticide permethrin.
- Use insecticide spray as directed to get rid of mosquitoes.
- Use bed nets to protect your sleeping area.
- Stay and sleep in screened-in or air-conditioned rooms.
- In tents, use a zip-up screen.