When you are pregnant, it is normal to feel paranoid about whether your baby will be healthy when it is born, and will your baby grow up to be a ‘normal’ child. The most recent reports about Zika virus will only act to send this anxiety through the roof. It is important that we look at the facts and make sure any precautions are taken to maximise the chance of a healthy baby in the event that you need to travel to an affected country or there is any spread to the Australian mainland (possible but unlikely in the foreseeable future).
Zika virus is a virus that is spread through mosquito bites. While it has been isolated from blood and semen, it seems that transmission is almost exclusively via mosquito bites. It is NOT spread from person to person through usual direct contact. As it is virtually always that infection is caused by mosquito bites, the main way to avoid infection is to avoid being bitten by mosquitoes. The mosquito that transmits the infection (the ‘vector’) is a particular kind of mosquito (aedes aegyptus) that exists only in TROPICAL areas. There is another species of mosquito (aedes albopictus) that lives in temperate areas which can also transmit the virus but this is less common. Hence, avoiding travel to areas where these mosquitoes thrive is recommended. Further, taking precautions to avoid mosquito bites also reduces the risk.
The most recent outbreak of Zika has been in Brazil. It has been noted that during the recent outbreak of Zika virus infection there has been a concomitant increase in the birth of babies with microcephaly. Microcephaly literally means small head. Many conditions can cause microcephaly, including other kinds of infections and specific developmental conditions. The concern with microcephaly is that it is usually associated with a smaller brain and related intellectual disability and developmental disorders.
While there is no doubt that Zika has been associated with increased risk of miscarriages and pregnancy loss, as well as microcephaly and intellectual disability, the exact way that it causes these serious problems is not completely understood. Further, how it affects development, and the impact of when during pregnancy is it contracted (ie how infection during each of the 3 trimesters), is also not completely understood. The most accurate thing that can be said is that the 20 fold increase in birth of babies with microcephaly in Brazil has occurred coincidentally with a large increase in the rate of Zika virus infection. Therefore, the logic is that the Zika virus is the likely cause.
Zika infection usually manifests in an illness about 2-12 days after being bitten by the infected mosquito. The illness caused includes fever (usually low grade: 37.8-38.5), rash, sore joints and conjunctivitis (at least 2 of these symptoms must be present to suggest the cause is possibly Zika virus). Other symptoms include headache, muscle pains and pain behind the eyes. Many infections can be ‘silent’ (or subclinical) whereby the infection can present without the patient being aware of having the infection. Even these ‘silent’ infections can be associated with a risk of having an affected baby. This is where the paranoia kicks in!!
Unless travel has occurred to an affected area, the likelihood is that there is another cause for the symptoms, including parvovirus, dengue fever, rubella, measles or other more uncommon infections. I routinely test all new pregnant patients for rubella and parvovirus, so I will be aware if you already have immunity to those particular viruses.
So what do I recommend:
1. Simply DO NOT GO to any countries where the offending mosquitoes thrives and/ or there is a current outbreak (check the CDC website (USA) or smarttraveller.gov.au. Sorry my lovely patients; NO trip to the Olympics! I don’t care what special corporate wiz-bang deal you may have been offered. Watch it at home!
2. Whilst the mosquito can live in temperate areas, there is currently no reason to believe the mosquitoes in Australia are affected. However, the virus has had outbreaks in Pacific Islands such as Samoa and the Cook Islands. It is possible that it could spread to temperate and tropical regions of Australia (FNQ, Northern territory, northern WA). I would possibly reconsider any trips to far north Queensland or pacific islands until we have a better grip on the situation.
3. It is sensible to be more strict about to covering up avoid insect bites. How do you do this:
- Wear long sleeves and long trousers.
- Apply insect repellent (DEET or picaridin containing). Forget the ‘natural’ repellants (citronella, eucalyptus, maleleuca, ultrasonic repellents). This is a situation where only tried and tested good ole chemicals will work.* The natural alternatives vary between useless (ultrasonic) to OK (oil of lemon eucalyptus) but only offer partial coverage and are simply not enough to protect you from Zika.
- Repellant can be applied directly to some skin surfaces but the best approach is to spray your CLOTHES and only apply repellent to EXPOSED skin surfaces. Do NOT apply repellent UNDER clothing.
- Purchase clothing/ bedding/ equipment pre-treated with permethrin or apply permethrin to these items.
- If overseas, use a mosquito net over the bed while sleeping.
*personally I feel the same when it comes to head lice treatment!! There are some things that require nothing less than chemical annhiliation….(just wait until your much loved little perfect baby turns into a mop-topped little toddler and comes home with a head full of lice. Trust me…)
With regards to insect repellent, it is appropriate to be cautious of pesticides. DEET, which is the main active ingredient in personal insect repellents, has NOT been shown to increase fetal abnormalities. When applied to skin it is absorbed into the circulation, thus a growing fetus is exposed to this pesticide. Therefore as explained above, it is more appropriate to apply DEET to clothes rather than skin. Another repellent is picaridin. It is a little stronger than DEET but does not last as long. Clothing and bedding itself can be treated with permethrin but it is not applied to skin.
It will be tempting to want testing to reassure yourself that you do not have Zika virus if you have travelled recently. This may be appropriate if you have been to one of the nominated countries that are affected, especially if you have had symptoms consistent with viral infection. At present the CDC in the US do not recommend testing for women with no symptoms and no evidence of fetal abnormality. This policy may change. The main basis of this policy is that the capacity for testing for this virus is currently very limited. We simply do not have the resources for a massive increase in testing, especially for the ‘worried well’ who have not even travelled to affected areas. Rest assured that this capacity is being reviewed and is likely to be ramped up in anticipation of an increased need to test women who have travelled to countries where Zika is already established or looks likely to be affected soon.
In the meantime I think the sensible approach is to avoid travel and step up your regime to avoid insect bites. (As you are probably aware I am not a great fan of women travelling during pregnancy anyway due to the unpredictable nature of pregnancy and the risks involved).
This infection is still being monitored and health agencies are active in trying to contain the spread and establish policies to protect pregnant women. In the meantime, watch this space!
Further information can be obtained from:
“There are concerns that pregnant women who become infected with Zika virus can transmit the disease to their unborn babies, with potentially serious consequences. The association between Zika virus and fetal malformations is still being investigated. However, rapidly accumulating evidence from the current outbreak appears to support a link between Zika virus infection and microcephaly and other serious brain abnormalities. Until more is known about Zika virus transmission in pregnancy and the association with adverse fetal outcomes, pregnant women should consider postponing travel to countries affected by the virus as authorities expand their list of places of concern.”
RANZCOG statement August 2016
The CDC website in the USA
Australian Department of Health
Countries affected by Zika:
I recommend that you appraise yourself of the most up to date list of countries through the Australian Department of Health website:
Insect repellants in Australia
- Aerogard – picaridin
- Bushman – DEET
- Off! – Picaridin
- Rid – DEET