Zika virus

The zika virus, abbreviated to ZIKV, is a mosquito-borne flavivirus closely related to the Dengue virus. The zika virus is transmitted through bites from mosquitos.

What are the symptoms?

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.

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.

Where is the ZIKV prevalent at the moment?

The zika virus is prevalent in large regions of Central and South America and the Caribbean, as well as in some countries in Southeast Asia and Africa. The outbreak phase in which many new cases were reported is now behind us, but the virus can still be transmitted by mosquitoes in the affected regions. However, bear in mind that the situation can change. For the latest information see the relevant website pages of the RIVM (Netherlands Institute for Public Health and the Environment).

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.

The zika virus and pregnancy

According to the WHO, there is now strong scientific evidence that points to a relationship between a ZIKV infection and pregnancy and the development of microcephaly in the foetus (a serious disorder of the brain of the foetus). The following measures are recommended if you are travelling to a zika virus region in Latin America.

  • Pregnant women: postpone your journey.
  • Women who are trying for a baby (travelling without their partner): postpone your efforts to fall pregnant until a month after leaving the region in which the zika virus is prevalent and, in the meantime, use condoms to prevent possible sexual transmission.
  •  Male partners of women trying for a baby: use condoms until a month after leaving the region in which the zika virus is prevalent.

If you are travelling to ZIKV regions in Africa or Asia, the likelihood that you will be infected with the virus is smaller. In this case, preventative measures are still recommended (read more), but pregnant women are advised not to make the journey. Whether or not to run the risk is a personal decision.

How can you prevent ZIKV infection?

Protection against a zika virus infection is mainly a question of avoiding mosquito bites and – in some cases – the temporary practising of safe sex. The guidelines are described below.

  • General: Follow these anti-mosquito measures, particularly during the day.
    • Clothes: wear as much clothing as you can (long sleeves, long trousers, socks and closed shoes);
    • DEET (mosquito repellent): during the day apply mosquito repellent (DEET) carefully and in accordance with the instructions:
      • Apply sufficient DEET to all exposed areas of your skin;
      • It is advisable to use products with a DEET concentration that is between 30-50 per cent (for young children and pregnant women it is advisable that the DEET concentration is less than 30 per cent);
      • DEET 30 per cent products can be applied up to four times a day, for DEET 31-40 per cent the maximum frequency is three times a day, and for DEET 41-50 per cent the maximum is twice a day.
    • Hotel room: Make sure your hotel room is mosquito-free (keep windows closed and only open them if you have good screens, if it’s available use air conditioning to keep the room cool);
    • Feeling poorly after your return: if you have feverish symptoms, always consult a doctor during the two weeks after a stay in a region in which ZIKV is prevalent.
  • Pregnancy: for pregnant women travelling to destinations where the zika virus is prevalent, the advice is described below.
    • If you are pregnant and you must travel to a region in which the zika virus is prevalent, the following advice applies:
      • Strictly adhere to the measures outlined above;
      • You can use DEET up to 30 per cent concentration throughout the pregnancy, but preferably no more, or not for longer, than is absolutely necessary for effective protection.
    • Pregnant women who have visited a region in which the zika virus is prevalent during their pregnancy are advised to contact their family doctor, midwife or gynaecologist. This is to ascertain whether further tests, for a ZIKV infection or to check the development of the foetus, are necessary.
    • Pregnant women are advised not to have unprotected sex with a man who has recently visited a region in which the zika virus is prevalent (see below, Sexual transmission).
  • Sexual transmission:
    To prevent the transmission of the virus through sexual contact, the following measures are advised:
    • General: condoms should be used in regions in which the zika virus is prevalent.
    • For men who do not have (or have not had) the symptoms:
      Use condoms for at least two months after returning from a region in which the zika virus is prevalent.
    • For men who have contracted the zika virus:
      Use condoms for six months after the symptoms have cleared up.

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)