Zika has been around for a while, since at least the 1950s. In the past it was not considered an important disease. It was rare, and most people who catch the virus do not feel sick. Sometimes people have mild symptoms, such as fever, rash, red eyes or sore muscles and joints. These problems usually go away after a few days. In very rare cases, people with Zika can develop more serious problems, such as a neurological problem called Guillain-Barré Syndrome. However, this syndrome may be triggered by almost any virus, including the flu.
Around 2007, Zika suddenly became much more common. With many more people catching Zika, doctors started to notice something scary. When women caught Zika during pregnancy, even if they felt completely fine, the virus could pass to their unborn babies. Some babies were born with very serious problems.
We do not know if this happens because the virus is changing, or if the virus has always done this and we are just noticing now that Zika is becoming much more common.
Either way, we know that while Zika is not dangerous for most people, the damage it can do to unborn babies makes it very dangerous for pregnant women.
Most women who are infected with Zika while they are pregnant will still have a normal, healthy baby. We think that about five to 15 per cent will have babies with problems caused by Zika. Unfortunately, that still means a lot of people. Thousands of babies in over 30 countries have been affected by Zika, and often they have severe problems.
Many have microcephaly, meaning the baby’s head and brain did not grow normally before birth and are very small. As the brain is so important for almost everything humans do, these babies can have a lot of disabilities, including trouble learning, moving, eating, seeing and hearing. Microcephaly is only one problem that babies can have when mothers catch Zika during pregnancy. Many others exist, most involving the brain. Some babies even die before they are born.
We think people can be infected with Zika virus in two main ways:
Not all mosquitoes can carry Zika infection. The two kinds of mosquitoes that carry it are Aedes aegypti and Aedes albopictus. (Since the scientific names are hard to remember, just think of them as Zika mosquitoes.) If this type of mosquito bites someone with the virus, the mosquito can get infected. If that same mosquito then bites you, you too can get the virus.
Although we have a lot of mosquitoes in Canada, we do not have Zika mosquitoes. That means you do not have to worry about catching Zika if a Canadian mosquito bites you. However, if you travel to countries that have Zika virus and Zika mosquitoes, you could catch it if you are bitten. Normally this is not a problem, as most people with Zika do not get sick. It is a different story for pregnant women. If you are pregnant or are planning to get pregnant in the next few months, it is best not to go to Zika countries. If you do go to a Zika country, do not get pregnant for at least a few months after you return.
A woman can also catch Zika by having sex with a man who has the virus. Pregnant women and those planning a pregnancy must be careful about having sex with a man who has been in countries with Zika virus and Zika mosquitoes. Zika virus can live in semen for up to six months. If you and your male partner spend time in a Zika country together, avoid having sex while you are there. You should also take precautions for at least six months after your male partner has lived in or travelled to a Zika country. If you do decide to have sex during this time, you must use good birth control to prevent pregnancy. Condoms are also necessary to prevent catching Zika from him.
The same advice applies if your male partner has been to a place with Zika and you are already pregnant. Avoid sex or use condoms to prevent getting infected with Zika for the rest of the pregnancy. Remember, most people with Zika do not feel sick. You must be careful even if your partner feels fine. He could have Zika without knowing it, and might pass it on to you. This is even more likely if he is feeling sick.
As far as we know, women who have sex with other women cannot give Zika virus to each other. The virus also does not seem to spread through breast milk, saliva or tears.
Most countries with Zika are in the southern hemisphere or are around the equator (see sidebar). Zika mosquitoes cannot live in places where it gets cold, such as northern countries or high up in the mountains.
If you or your partner are planning a trip, remember that Zika is not the only dangerous disease you could catch. Before travelling to any exotic, tropical or developing country, it is always a good idea to talk to your health care provider and to visit a travel clinic. This is true even if you have lived or travelled there before. Get professional advice before you buy your tickets, especially if you are already pregnant. Your doctor may recommend against visiting an area where you were planning to go. If your plans are flexible, ask for recommendations on other places that are safer for pregnant women and their partners. There are many warm and wonderful places to visit that do not have Zika virus or Zika mosquitoes.
If you must visit an area with Zika virus, your care providers can advise on how best to protect yourself from Zika and other diseases. Almost all insect repellents are safe to use in pregnancy. The ones with DEET work well to help protect you from mosquitoes. Using window screens and bed nets, staying inside buildings where there is air conditioning, and wearing long sleeves and long pants can also help prevent bites. Since most Zika mosquitoes bite in the daytime, take steps to prevent mosquito bites during the day as well as at night.
Avoiding Zika infection is the best way to protect your baby. If you do catch Zika, there is no way to cure it, nor can you prevent your unborn baby from developing problems due to Zika. Although you might not even know you have Zika infection, it can still affect your baby.
If you are pregnant or plan to get pregnant soon, and if you or your sexual partner have been in a country with Zika, talk to your doctor or midwife. They can help you decide when it will be safe for you to get pregnant. If you are already pregnant, your blood and urine can be used to test for Zika infection. As well, they can check with ultrasound to make sure your baby looks healthy.
We are safe from Zika here in Canada. You do not need to worry about Zika as long as you and your partner stay away from Zika countries for a few months before you get pregnant, and throughout your pregnancy. This is the best way to make sure Zika does not affect your baby. However, if you or your partner must be in a Zika area just before getting pregnant or during your pregnancy, it is best to talk to your doctor or midwife before you go. They can advise you about how to lower your risk of catching Zika, and arrange the tests you will need.