Zika virus

Zika virus disease is caused by the Zika virus. For most people, the infection is very mild and leaves no long-term problems.

In pregnancy, though, it can be harmful. It can lead to complications and birth defects in the baby, in particular an abnormally small head (microcephaly).

Zika virus does not naturally occur in the UK.

Zika virus has been reported in these areas:

• Africa
• Asia
• Australia and the Pacific region
• Caribbean
• Central America
• South America
• North America

Most people who catch Zika virus don't have any symptoms at all. When symptoms do appear, they are usually mild and start 3 to 14 days after the infection has been caught. They last around 2 to 7 days.

The symptoms people commonly report are:

• 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

There's no specific treatment for the symptoms of Zika virus. Drinking plenty of water and taking paracetamol may help ease them.

• you feel unwell after returning from a country that has malaria as well as Zika virus

Zika virus and malaria can cause similar symptoms, so your doctor needs to rule out malaria.

Zika virus is mainly spread by mosquito bites. Unlike the mosquitoes that spread malaria, this type of mosquito mainly bites during the day, from sunrise to sunset.

If a woman is infected when she is pregnant, the virus can spread to the baby and may cause harm. This is called 'Congential Zika Syndrome'.

Less commonly, Zika virus can be spread from:

• a person with the infection to another during unprotected sex
• through blood transfusions or organ transplants

If you are planning international travel, you can use this A to Z guide to check if your destination has Zika virus. There is no vaccine or medicine to prevent Zika virus infection. In a country with a risk of Zika virus, you can lower your risk of catching the virus by avoiding mosquito bites.

Pregnant women should avoid or postpone non-essential travel to areas with a risk of Zika virus transmission. If you are going abroad, Travel Health Pro has information on the risk of Zika virus and detailed travel advice. There is further information about travel health and vaccinations too.

If you want to lower your risk of Zika virus infection, avoiding mosquito bites is one of the best ways to do it. The methods that work best should be used both in the daytime and at night. There are a few simple steps you can take to keep the mosquitoes off you.

• cover your skin with light, long-sleeved clothing, and long trousers, dresses or skirts
• apply insect repellent to any skin that is not covered by clothing, including your face and neck
• remember to reapply insect repellent frequently, and after sunscreen has been applied
• rest or sleep under a mosquito net that's been treated with an insecticide
• use effective air conditioning indoors
• make sure window and door screens are closed when you are indoors

The most effective repellents contain 50% diethyltoluamide (DEET). Pregnant or breastfeeding women can use these.

You can find more information on preventing mosquito bites from Travel Health Pro.

If a pregnant woman catches Zika virus infection, her baby can be born with birth defects. One of these is microcephaly, where the head is abnormally small, and it can go along with abnormal brain development. Together these problems are known as congenital Zika syndrome.

Zika virus infection can also bring complications in the pregnancy itself, including stillbirth or premature delivery.

Pregnant women are advised to avoid non-essential travel to areas where there is a risk of Zika virus, or to put it off until after the pregnancy.

If you do plan to travel, talk it over with your midwife, obstetrician or a travel clinic first. And if the trip can't be avoided, there are steps you can take to help avoid infection.

• take extra care to avoid being bitten by mosquitoes
• use condoms during vaginal, anal and oral sex while travelling and during your pregnancy
• see your doctor or midwife if you have recently returned from an area with Zika virus and tell them where you have been, even if you have not been unwell

Your midwife or hospital doctor will discuss the risk with you and advise whether you need any additional tests.

If you are trying to get pregnant, talk about your travel plans with your doctor, practice nurse or a travel clinic first.

Women are advised to avoid unprotected sex and not to start a pregnancy while travelling in an area with Zika virus. You should also avoid unprotected sex and starting a pregnancy for 8 weeks after you return home if you are a woman, or for 3 months if you are a man.

If you're worried that your unborn baby may be affected by Zika virus, speak to your midwife or doctor and ask for advice. Even after they've reassured you, you can still ask for counselling if the worry doesn't go away. Counselling can also be offered if you feel more stressed or anxious than usual.

Zika virus can cause Guillain-Barré syndrome (GBS), a serious condition of the nervous system. The risk of getting GBS after a Zika virus infection is very low.