Which areas are currently affected by the Zika virus? Should everyone avoid travel to these areas or only pregnant women?
The majority of the countries that are affected by the Zika virus are in the Caribbean. Many of the Caribbean Islands, including large islands such as Jamaica, Dominican Republic, Barbados and US Virgin Islands, as well as Mexico and other countries in Central and South America are affected.
The current Zika virus outbreak that most people are aware of, began in South America, so that's where they're seeing the heaviest burden of cases.
With regards to travel, I think that everyone should be cautious about traveling to countries where there is current Zika transmission. While certainly pregnant women are the most susceptible to side effects such as brain damage in their children, there's actually another condition called Guillain-Barré Syndrome that a lot of doctors in those countries are also concerned is associated with the Zika Virus.
Guillain-Barré syndrome can affect anyone of any age and, for that reason, I think everyone should be cautious and be aware when they're traveling to countries effected by the Zika virus.
For people that are traveling to Zika-affected areas, what are the best methods of protection?
As far as we know, the best method of protection is using a proven insect repellent. Certainly, DEET is considered to be the most effective type of insect repellent.
Typically, a DEET concentration of 20 to 30% protects against 90% of all mosquito and tick bites, so that's the first line of defense.
For people who are nervous or weary of using DEET, there are other types of insect repellent such as lemon of eucalyptus oil or permethrin, which can also protect against mosquito bites.
What are the main things to consider when choosing an insect repellent?
The main thing that you want to consider is how long you plan on being outdoors in an area where you're at risk of mosquito bites. For instance, a DEET concentration of under 20% will typically give you about 2 to 4 hours of protection, but if you anticipate staying outdoors for 6 hours or more, you may prefer higher concentrations.
The other thing that's really important is that you should only treat areas that are going to be exposed. If you're wearing a shirt with short sleeves, for example, you should only apply the insect repellent to the exposed skin. You don't have to apply it to the chest, back and other covered areas.
Are there any extra considerations for children and pregnant women?
Most insect repellents are safe to use on children and during pregnancy. Since pregnant women are at the highest risk of serious side effects, I would definitely recommend using DEET because it is proven to be the most effective.
For children, insect repellents containing up to 30% DEET are considered safe to use, but you should limit its use to children who are older than 2 months of age.
What do you recommend for children under 2 months?
You should use long sleeve clothing and hats to protect the majority of the skin, that’s very important.
Does a higher concentration of DEET mean the repellent is more effective?
No. It's really important to remember that a higher percentage of DEET is not necessarily more effective; it just means that it will last longer.
How long does insect repellent give protection for and how often should it be reapplied?
Most preparations containing at least 30% DEET will give you up 5 or 6 hours of protection; some preparations last even longer. Certainly, if you expect to be outdoors longer than that, you may need to reapply.
Once you are out of an exposed area, then you should wash off the insect repellent because some people notice some skin irritation. Otherwise, if you don't expect to be outside for longer than 6 hours, you don't need to reapply unless you plan to engage in water activity. If you apply DEET and then go swimming, you should reapply after getting out of the pool, to make sure that you're still covered.
Other than insect repellents, are there any other ways you can protect yourself from the Zika virus when traveling to affected areas?
As well as wearing long sleeves and long pants, you can actually also find pre-treated clothing. Permethrin is really the go-to insect repellent used on clothing.
You can buy clothing that's already been treated with insect repellent, but be aware that with each wash a little bit of the insect repellent will come off.
You can also buy permethrin spray to spray directly on clothes. Again, you should make sure you only treat outer layers of clothing and not use the permethrin spray on any bras or underwear because you don't need to treat any areas of the skin that will not be exposed.
What should you do if you are bitten by a mosquito?
If you notice a bite and it's itchy or bothersome, then you can use over-the-counter cortisone cream or an antihistamine cream to help control the itch. You really must try to avoid scratching it, if possible, because scratching the skin can cause it to tear and, in very rare instances, can lead to a skin infection.
Are there any myths about Zika that you’d like to dispel?
I'm not sure if I would call them myths, but there are a couple of things that I think are very important to know. At this time, it's unclear how long the virus is present in your system. One thing that I would say is that, if you don't have to travel to a Zika infected area, you should avoid it. If you're a young woman who's thinking about having kids, you may still have the virus in your system, even if it was a month ago that you travelled.
About 80% of people who are affected with the Zika virus won't have any symptoms at all. It's really important to break that into two points: firstly, you can have the Zika virus without having symptoms and, secondly, the Zika virus can potentially stay in your blood stream for an extended period of time. At this point, we don't know how long the virus stays in your system.
What do you think the future holds for the Zika virus?
I think the primary goal from a medical standpoint, is to see whether or not a vaccine can be developed. I think it's very difficult to envision an eradication of mosquitoes. Obviously, a lot of communities are taking very aggressive steps to minimize exposure to mosquitoes, but I think down the line, a Zika vaccine will be really important, especially because the potential side effects are so severe.
We really haven't seen a mosquito-borne illness with such severe symptoms as the Zika virus in a long time, so hopefully a vaccine will be the next step.
Where can readers find more information?
If you want more information about insect repellents, visit EPA.gov
The World Health Organization website and the Centers for Disease Control and Prevention (CDC) website also have great information about the Zika virus.
You should also visit your local government website to read about updated travel notices, but the CDC and World Health Organization also have travel notices.
About Dr Aguh
Crystal Aguh MD is an Assistant Professor in the Department of Dermatology at Johns Hopkins hospital. She obtained her undergraduate degree from Duke University and obtained a medical degree with honors from the University of Pennsylvania School of Medicine.
Her clinical interests include complex medical dermatology, ethnic skin, procedural dermatology, and international health.