Some short answers to hard questions about Zika virus

Where did Zika come from?

Zika virus was named after the Zika forest in Uganda, where it was first identified in 1947. From the 1950s to 2007 it was a disease seen in only a narrow band around the equator in Africa and Asia, but since 2007 it has spread to the Americas where is spread very rapidly.


Why has this pandemic happened now?

Until 2007 the virus circulated between monkeys and mosquitos, and was rarely seen in man. There was a low level of infection amongst people, but levels of immunity are high so the disease rarely spread. The problem is that this disease hasn’t been in the Americas before, so there is no immunity amongst the population. When the disease hit, it could therefore spread extremely rapidly. There are theories that suggest that global warming may have allowed the Aedes aegypti mosquito (the most common carrier of the disease) to thrive further from the equator, thus greatly increasing the spread of disease. We aren’t sure how many other species of mosquito can carry and spread Zika, but it has been found in at least ten others in recent months. Increases in trade and travel have spread these mosquitos all over the world, and A. aegypti is now seen extensively all over the world.


Is it safe to have sex after traveling to a Zika positive country?

This really depends on whether or not you want to have a baby. Half of all pregnancies are unplanned, so if you are in a Zika infected place then be sure to use birth control very carefully.


Is there a test for Zika?

Only one in five people who contract Zika virus have any symptoms so not being ill doesn’t mean that you haven’t had the disease. There isn’t currently any quick test available. It is possible to be blood or urine tested and doctors can check for the presence of antibodies in your blood however, as this disease is very similar to others such as yellow fever and dengue, false positives and false negatives may occur.


I want to get pregnant but my partner and I have been to a Zika infected area, is it safe to try for a baby?

New data shows that Zika can hide in the testes or prostate for at least two months after a man is infected, and can be transmitted to women sexually. Advice from the World Health Organisation (WHO) is that, if you’ve been to a Zika infected area and have had no symptoms, don’t have unprotected sex for at least 8 weeks. IF you did have any symptoms of Zika (fever, sore eyes, joint pain, headaches and a rash) then don’t have unprotected sex for 6 months and do not try to conceive during this time.


What does Zika virus do to an unborn baby?

The most devastating effect of Zika virus is its ability to infect unborn babies and prevent the correct development of their brain. We aren’t sure exactly how this happens yet but it is likely that the radial glial cells, which form the initial “scaffolding” that guides other brain cells to the right places, are the main viral target. The result is that babies are born with microcephaly, where the brain is under developed and nerves to the eyes and ears may also be damaged. The severity varies, probably depending on how developed the brain was when the virus hit. The results can however be terrible, with babies suffering from constant seizures or permanently rigid limbs.


Does it matter when in her pregnancy a woman is infected?

Any time in the pregnancy is dangerous. In lots of other infections, the earlier the baby is infected the worse it is, however with Zika we aren’t sure this is the case. Some mothers infected in late pregnancy have had terrible consequences including the sudden death of the infant in the womb. Some experts also suggest that there may be long term consequences for babies infected with Zika even if they look normal at birth, such as blindness, deafness and mental disabilities later in life.


What can I do to avoid catching Zika virus?

This is really quite simple. Don’t go to Zika infected countries if you have any intention of getting pregnant in the next six months unless you really have to. If you absolutely must go then all precautions to avoid getting bitten by mosquitos should be taken, including wearing long sleeves and trousers, sleeping under a mosquito net, wearing mosquito repellent and using insecticide before bed. If you or your partner have any symptoms then wait for six months before trying for a baby. It may be a frustrating wait, but it’s just not worth the risk to your baby to rush!