Zika virus

The zika virus, abbreviated to ZIKV, is a mosquito-borne flavivirus closely related to the Dengue virus.

How do you become infected with the zika virus?

The zika virus is transmitted through bites from the Aedes mosquito, the same mosquito that carries Dengue and Chikungunya. These mosquitos are usually active during daylight hours and often live in buildings in urban areas. It is also possible, though much more rare, for a foetus to contract the virus in the womb if the mother has become infected with zika.

How can you prevent ZIKV infection?

Human-to-human transmission does not occur. You cannot become infected through physical contact with an infected person, for instance through touch, shaking hands, sneezing and coughing, toilets etc. ZIKV is also not transmitted through contact with objects or animals.

What is the incubation time for the Zika virus?

The incubation time is the time that elapses between the initial infection (bite from an infected mosquito) and the appearance of the first symptoms. The incubation time for ZIKV has not been clearly established, but is probably between three and 12 days.

What are the symptoms?

A zika virus infection is generally mild. It is estimated that 75% of people who become infected with ZIKV experience no symptoms (i.e. a high rate of asymptomatic infection). Symptoms, if they occur, are one or more of the following:

  • Sudden onset with fever;
  • Muscle and joint pain (often in hands and feet);
  • Skin rash (often starting in the face and spreading);
  • Headache (especially “behind the eyes”);
  • Nausea, vomiting, abdominal pain and/or diarrhea;
  • People infected with the zika virus generally recover without treatment and without any serious lingering symptoms. The number of people who have died of the zika virus is very low.

What possible complications are associated with ZIKV?

There are indications that ZIKV may lead to two complications:

  • Babies born with birth defects to mothers who became infected with the zika virus during pregnancy. The main defect linked to ZIKV is microcephaly, which is a serious abnormality of the skull and brain.
  • In adults the virus may lead to the neurological condition Guillain-Barré Syndrome (GBS), which causes rapid-onset muscle weakness and paralysis. Most people with Guillain-Barré Syndrome make a full recovery without any lingering symptoms, but long-term and intensive treatment may sometimes be required.Both these complications are rare and the suspected link with zika has not yet been proven. However, statistical evidence does suggest a possible link. The WHO (World Health Organization) is carrying out research to establish whether there really is a link.

Who is most likely to suffer from complications?

The following groups are thought to be at a higher risk of complications:

  • Pregnant women and their unborn babies;
  • People with a serious immune deficiency, e.g. due to recent chemotherapy or HIV infection, with a low CD4 cell count.A link to ZIKV has also not been proven for these at-risk groups and further research is required.

Can I find out whether I have (had) the zika virus?

Yes, with a blood test.

Is there a treatment for the zika virus?

No, there are no medicines available specifically to treat the zika virus. They are also unnecessary, because people recover spontaneously from the virus. Only in the event of (possible) complications might it be necessary to carry out a targeted investigation to provide specific treatment.

Is there a risk to breastfeeding babies?

No, there is no indication that the Zika virus is transmitted through breastfeeding from mother to child. Moreover, even if newborns and infants become infected, they are no longer at risk of the abnormalities.

Can I catch the zika virus from someone who is infected?

No, that is impossible. Infection only occurs through mosquito bites and not through human-to-human contact. This means that social contact (talking, touching, sneezing, coughing) carries no risk, even if someone has ZIKV.

Can the zika virus be sexually transmitted?

  • There is strong scientific evidence that the zika virus can be transmitted by sperm. In all instances, transmission took place via men who had symptoms of the disease. The extent and duration of the risk of transmission via sexual contact is as yet wholly unclear. The WHO is still researching the nature and risk of transmission via sexual contact. To prevent transmission of the virus via sexual contact, we currently advise the following:
    Men who have never had symptoms of the disease: Use a condom for at least two months after returning from a zika infected country.
  • Men who have suffered a zika infection: Use a condom during the first six months after the symptoms of the disease have disappeared.
    Owing to the possibly serious consequences of zika infection for an unborn child, men who have been to a country where zika occurs and who have a pregnant partner are advised to use a condom for the remainder of the pregnancy. This minimises the risk of zika infection during pregnancy.

How long does the zika virus remain in the body after infection?

As far as anyone knows, the zika virus stays in the body for up to a week after the appearance of the first symptoms i.e. a maximum of three weeks after the initial infection. The body is virus free thereafter.

Can I become reinfected if I have already had ZIKV?

As far as anyone knows, a zika virus infection leads to lifelong immunity. In other words, once you have had the zika virus, it is very unlikely you will catch it again.

Can I still get pregnant if I have had the zika virus?

Yes, you can. There is no risk to the foetus in pregnancies. However, we advise you always to contact your doctor or specialist before starting a new pregnancy.

Where is ZIKV occurring at the moment?

The zika virus is currently found in Central and South America, the Caribbean, and Southeast Asia. The situation is changing all the time and the WHO (World Health Organization) expects the epidemic to spread to other areas.

If you would like up-to-date information about where ZIKV is currently being found here.

Is there an infection risk in the Netherlands?

The zika virus has been confirmed in a number of patients in the Netherlands. But no one has become infected in the Netherlands. It is highly unlikely that anyone will contract the virus in the Netherlands from mosquitos entering the country by plane or in cargo arriving from a zika-infected area.

Is there a vaccination or prophylaxis for the zika virus?

There is no vaccination for ZIKV. There is also no known preventative medicine (prohylaxis) to prevent symptoms from occurring.

How can I protect myself against the zika virus?

Protection against a zika virus infection comes down to preventing mosquito bites. These are the guidelines:

General: Take good anti-mosquito precautions, especially during the day:

  • Clothes: Wear long clothes (preferably light-coloured) as much as possible (long sleeves, long trousers, socks and closed shoes);
  • DEET (anti-mosquito lotion): Carefully follow the instructions for mosquito repellent (DEET) during the day:
    • Apply sufficient DEET to all uncovered skin;
    • It’s advised to use products with a DEET percentage from 30 – 50% (young children and pregnant women is advised to use DEET less than 30%);
    • DEET up to 30% may be applied a maximum of four times a day, DEET from 31 – 40% a maximum of three times a day, and DEET from 41 – 50% a maximum of two times a day.

Hotel room: Keep your hotel room mosquito free (keep windows closed, only open them if there are good screens, use air conditioning to keep the room cool.)

  • Mosquito nets: If it is not possible to sleep in a room that is free of mosquitos, take an impregnated mosquito net with you (i.e. one treated with an insect repellent, such as permethrin);
  • Ill on return: If you become ill with a fever within two weeks of returning from a zika-infected area, always consult a doctor.

Pregnant or possibly pregnant: For women who are pregnant or possibly pregnant, the following advice applies for destinations where the zika virus occurs:

  • If you are (possibly) pregnant, consider whether your journey to the zika-infected area is necessary and perhaps postpone your trip;
  • Carefully follow all the preventative measures given above;
  • DEET up to 30% may be used throughout the pregnancy, though preferably not more or for longer than is necessary for good protection;
  • Pregnant or possibly pregnant women should always consult a doctor if they become ill with a fever within two weeks of visiting a ZIKV-infected destination.

Sexual transmission: To avoid transmission of the virus via sexual contact, we advise as follows:

  • General: always use a condom when staying in a zika infected area.
  • Men who have never had symptoms of the disease: Use a condom for at least two months after returning from a zika infected region.
  • Men who have suffered a zika infection: Use a condom during the first six months after the symptoms of the disease have disappeared.

This Q&A has been compiled by KLM Health Services based on advice from the following organisations:

  • CDC (Centers for Disease Control and Prevention)
  • ECDC (European Centre for Disease Prevention and Control)
  • RIVM (Rijksinstituut Volksgezondheid & Milieuhygiëne)
  • LCR (Landelijk Coördinatiecentrum Reizigersadvisering, DEET-folder)
  • WHO (World Health Organization)