By Roger Marwood FRCOG
The Zika virus is a relatively new virus that is rapidly spreading through Brazil and the Americas.
It is important because it can affect pregnant women and may cause serious brain damage to their babies.
It is transmitted by a mosquito bite and once the virus multiplies in the mother , it can cross over the placenta and cause a problem in the baby’s brain development. The defect is called microcephaly , which means small head , and therefore, small brain. It is likely that infection in the early part of pregnancy carries the greatest risk.
The mosquito is called Aedes aegypti , and is unusual in that not only does it carry the Zika virus, but it also carries the organisms responsible for two other diseases, namely, Dengue Fever and Chikugunya Disease. It also likes to bite during the day and not just at nighttime!
The chances of a damaged baby after infection are not clearly known , and there is currently a lot of uncertainty about the severity of the outbreak , but all experts are agreed that it is serious and appears to be rapidly increasing.
Of particular concern is the work from recent studies that suggest that the virus may be spread by sexual intercourse as well as transfusion, breast feeding and possibly organ transplantation.
Most people (80%) do not get any significant symptoms! The commonest symptoms are of a mild fever, a red raised non blistery skin rash, red eyes (conjunctivitis but without the discharge) , joint pains.
Symptoms may arise up to 2 weeks after a mosquito bite. Generally the symptoms are mild and not disabling, and do not last for more than a week. Very rarely they can be associated with a severe neurological condition causing weakness and loss of muscle strength.
Diagnosis and Treatment
There is no specific commercially available test for Zika virus. There is , however, a special and specific blood test that can be arranged at the hospital if you are thought to be high risk. This test will also test for Dengue and Chikugunya.
There is no specific treatment to eradicate the virus.
At the moment there is no Vaccine, and antiviral drugs do not seem to help.
General support and tablets such as Paracetamol will be helpful .
If there is no evidence of Dengue then aspirin or non-steroidal preparations like Ibuprofen may be helpful.
An early scan should be able to tell if the baby’s brain and head is developing normally. Sometimes the scans may need to be repeated at 2-4 weekly intervals.
Advice to Travellers
Avoid travel to areas affected by the virus when you are pregnant.
If you do go the affected countries, then you must take every precaution to avoid mosquito bites:-
- Cover up , including arms and legs with loose fitting clothes.
- Use insect repellent . DEET (20% or more) is safe and effective, and can be applied after sunscreen. It is safe to use in pregnancy and lactation, if used as directed on the packaging.
- Sleep under an intact and impregnated mosquito net.
- When you return seek advice from your midwife or doctor.
- If your partner has just returned from one of the affected countries, use condoms for up to 4 weeks , to prevent any infection transmitted by sexual contact
You may find the NHS website useful too.