Increase in cases of congenital skull and brain abnormalities following Zika virus infection; Brazil and French Polynesia


The European Centre for Disease Prevention and Control (ECDC), the HSE and HPSC are advising women who are pregnant or who might become pregnant to ensure that they make every effort to protect themselves against biting mosquitos while travelling in areas affected by Zika virus disease. Zika virus infection is a febrile illness caused by Zika virus (ZIKAV). ZIKAV is spread by infected biting Aedes mosquitoes and can be found in a number of countries in the tropics (see here for a map of affected areas).

Authorities in Brazil and French Polynesia who have been monitoring extensive outbreaks of ZIKAV disease in these countries (each consisting of many thousands of ZIKAV cases) have begun - in the last two months - to see the emergence of large numbers of brain and skull abnormalities in new born babies. Currently there are 17 cases of brain abnormality under investigation in French Polynesia and more than 700 cases of microcephaly in north-eastern Brazil (microcephaly is a congenital condition in which a baby is born with an abnormally small head and it is frequently associated with markedly impaired intellectual development).

Until more information becomes available, HSE and HPSC are advising women who are pregnant or who might become pregnant to be aware of this risk and to make every effort to protect themselves against biting mosquitos while travelling in areas affected by ZIKAV illness (which corresponds very closely with malarious areas in the world).

Pregnant women (or those who are at risk of pregnancy) should discuss this with their Travel Physician and their Obstetrician (if they are already pregnant and booked in). Pregnant women should bear in mind that different mosquitoes (carrying different diseases) can bite at different times of day – they should ask locally which mosquitoes they need to protect themselves against (Aedes mosquitoes that carry ZIKAV tend to bite in the morning and late afternoon; Anopheles mosquitoes that carry malaria tend to bite at night). If pregnant or at risk of pregnancy they should remember to:

  1. Ensure they know when local mosquitos are likely to be biting
  2. Avoid areas where mosquitoes are likely to congregate (i.e. stagnant water)
  3. Wear appropriate clothing: long-sleeved shirts, long pants, boots and socks
  4. Protect their rooms: mosquito bites can be reduced by air conditioning, insect-proof screens
  5. Protect their beds: Bed nets and cot nets should be used if rooms are not adequately screened or air conditioned
  6. Use insect Repellents: CDC and the UK’s Bumps (run by the UK Teratology Information Service) advise that pregnant women can use DEET as a mosquito repellent, if they ensure to a) use it sparingly and b) wash it off when away from risk of biting mosquitoes, as it is a chemical applied to the skin. The risk to a pregnant woman's unborn baby, certainly from malaria, would outweigh any potential risk from DEET.

On December 3, 2015, PAHO (the Pan American Health Organization) issued an alert on ZIKAV and the clusters of congenital neurological disorders recommending to its member states (in North and South America) that they:

  1. Establish and maintain the capacity to detect and confirm Zika virus cases, 
  2. Prepare healthcare facilities for possible increase in demand at all healthcare levels
  3. Ensure the specialized care for neurological syndromes, 
  4. Strengthen their antenatal care,
  5. Continue efforts to reduce the presence of mosquito vectors through effective vector control strategies and public information and communication

The alert highlights the fact that, in Brazil, here has been a sudden, 20-fold increase in cases of microcephaly in 2015 in comparison to 2010.  The distribution of the cases of microcephaly mirrors closely the distribution of ZIKAV disease.  In addition, because of the high levels of ZIKAV disease, serious cases with complications are beginning to appear; there have now been tree deaths due to ZIKAV in Brazil, who in adults and one in a new-born.

Full information on ZIKAV disease is available on the HPSC website. Details of General Practitioners listed with the Irish Society of Travel Medicine are available on their website.

Updated: 3/12/2015