Zika virus disease is mainly spread by mosquitoes.
For most people it is a very mild infection and is not harmful. However, it may be more serious for pregnant women,
as there is evidence it causes birth defects – in particular, abnormally small
heads (microcephaly).
Zika does not naturally occur in the UK or USA.
Zika outbreaks have been reported in the Pacific Islands, South and
Central America, the Caribbean, Africa and parts of South and South East
Asia.
If you plan to travel to an affected area, seek
travel health advice before your trip. Travel advice is tailored to
you and based on the level of risk (high, moderate,
low) for the country you are travelling to.
It is recommended that pregnant women should:
- postpone
non-essential travel to areas at high risk of Zika virus
transmission, and
- consider
postponing non-essential travel to areas at moderate risk of Zika virus
transmission until after pregnancy.
Schematic diagram showing the Zika virus can be transmitted in the endemic areas.
High-risk areas are where there are current
outbreaks of Zika virus, or where there has been an increase in the number
of cases acquired locally, through mosquito bites. If you travel to an affected area, you can reduce
your risk of catching the virus by using insect repellent and wearing loose
clothing that covers your arms and legs.
Symptoms of Zika virus infection
Most people do not have any symptoms. If symptoms do
occur, they are usually mild and last around two to seven days. Commonly reported symptoms include:
- rash
- itching
all over the body
- fever
- headache
- joint
pain (with possible swelling, mainly in the smaller joints of the hands
and feet)
- muscle
pain
- conjunctivitis
(red eyes)
- lower
back pain
- pain
behind the eyes.
How you catch Zika virus infection
Most cases of Zika virus disease are spread by
infected mosquitoes biting humans. Unlike the mosquitoes that spread malaria,
affected mosquitoes (the Aedes mosquito) are most active during the day,
especially during mid-morning, then late-afternoon to dusk. There have been a small number of reports of Zika
virus being passed on through sexual intercourse, although the risk
is thought to be low.
Schematic diagram showing the chronology of discovery and spread of the Zika virus.
Reducing your risk of Zika virus infection
Before travelling, you must seek travel health advice from
your GP/practice nurse or a travel clinic ideally four to six weeks before you
go.
To reduce your risk of infection, you should avoid
being bitten by an Aedes mosquito. The most effective bite prevention methods,
which should be used during daytime and night-time hours, include:
- Using
insect repellent that contains DEET (N, N-diethyl-meta-toluamide) on
exposed skin, after sunscreen has been applied. DEET can be used by
pregnant or breastfeeding women in concentrations up to 50%, and in
infants and children older than two months. It should not be used on
babies younger than two months.
- Wearing
loose clothing that covers your arms and legs.
- Sleeping
under a mosquito net in areas where malaria is also a risk.
Advice for pregnant women
Scientists have concluded that there is enough
evidence to show that Zika virus infection is a cause of birth
defects, including microcephaly (this means the baby will have an
abnormally small head and can be associated with abnormal brain development).
This is also known as congenital Zika syndrome. It is therefore recommended that pregnant women
should:
- postpone
non-essential travel to areas at high risk of Zika virus
transmission, and
- consider postponing non-essential travel to areas at moderate risk of Zika virus transmission until after pregnancy.
Schematic diagram describing how infection with the Zika virus can be prevented.
Discuss your travel plans with your doctor/ GP/ practice
nurse or a travel clinic. If travel is unavoidable, then you should take extra
care to avoid being bitten by mosquitoes. If you and your partner are currently in an area
with high or moderate risk of Zika virus transmission, make sure you use
condoms during vaginal, anal and oral sex while travelling and for the duration
of your pregnancy.
If you are pregnant and have recently returned from
an area with high or moderate risk of Zika virus transmission, you should see your GP or
midwife and mention where you have been, even if you have not been unwell. Your
midwife or hospital doctor will discuss the risk with you and can arrange an
ultrasound scan of your baby to monitor growth. If there are any issues, you will be referred to a
specialist foetal medicine service for further monitoring.
Zika virus is most likely to be detected by
currently available tests when symptoms are present. If you are currently
experiencing Zika symptoms, contact your GP, who will decide whether
investigations are necessary. Investigations might include a blood test and/or
an ultrasound test if you are pregnant. Screening tests for Zika for those without symptoms
are not available.
Advice for women trying to get pregnant
If you are trying to get pregnant, discuss your
travel plans with your GP, practice nurse or travel clinic. You should take
extra care to avoid being bitten by mosquitoes. It is recommended that you avoid becoming pregnant
while travelling to an area with high or moderate risk of Zika virus
transmission, and for eight weeks after you return home. It is
also recommended that you take folic acid supplements for 28 days before
trying to get pregnant.
If you have experienced Zika symptoms within two
weeks of returning home, it is recommended that you wait eight weeks after full
recovery before you try to get pregnant. If your male partner has travelled to an area with
high or moderate risk of Zika virus transmission, you should use effective
contraception to prevent pregnancy and condoms during vaginal,
anal and oral sex to reduce the risk of sexual transmission. These measures
should be taken during travel and for six months:
- after
start of symptoms (if he does experience Zika symptoms or
a Zika virus infection has been confirmed by a doctor)
- following
his return home (if he has no Zika symptoms).
How Zika virus infection is treated
There is no specific treatment for Zika virus
symptoms. Drinking plenty of water and taking paracetamol may
help relieve symptoms. If you feel unwell after returning from a country
that has malaria as well as being high or moderate risk for Zika virus
transmission, you should seek urgent (same day) advice to help rule out a
malaria diagnosis. If you remain unwell and malaria has been shown not
to be the cause, seek medical advice.
Schematic diagram showing the advice by the World Health Organization (WHO) and the Pan American Health Organization (PAHO) about the treatment of the Zika virus.
What if
I'm worried that my baby has been affected by Zika?
Speak to your midwife or doctor for advice. If you
are still concerned after receiving assurances from your healthcare
professional and feel anxious or stressed more than usual, you can ask your GP
or midwife for referral to further counselling.
Zika virus and blood donation
As a precaution, the NHS Blood and Transplant service has
recommended that people who have travelled to areas with high or moderate risk
of Zika virus transmission wait 28 days before donating blood.
If you want to know whether any recent foreign
travel temporarily bars you from giving blood, you can call their National
Contact Centre on 0300 123 23 23.
Zika virus and Guillain-Barré syndrome
Scientists now believe that Zika virus is a cause
of Guillain-Barré syndrome (GBS), a
serious condition of the nervous system. The risk of developing GBS following a Zika virus
infection is currently unknown, but thought to be very low.
Information about you
If you have been infected with Zika virus, your
clinical team will pass information about you on to the National Congenital
Anomaly and Rare Diseases Registration Service (NCARDRS). This helps scientists look for better ways to
prevent and treat this condition. You can opt out of the register at any time.
Further reading
Public Health England. Zika virus: clinical and travel guidance.
Royal College of Obstetricians and
Gynaecologists. Q&As on Zika and pregnancy.
World Health Organization. Zika virus fact sheet.
Travel Health Pro. Zika virus – update and advice for travellers
including pregnant women.
