Somewhat unbelievably given the preponderance of violence today, humans are not responsible for the most human deaths worldwide.  This distinction instead belongs to that annoying buzzy insect, the mosquito.  Mosquitoes are like an Uber for infectious pathogens hitching a ride to and from nice cozy destinations such as humans.  There are numerous viruses, bacteria, and even fly larvae (I dare you to watch this video) taking mosquito Ubers, but the one I want to talk about today is called Zika.

Zika virus causes a mild flu-like illness in just 1 in 5 people who are infected, but it is not the cold it causes that is worrisome.  The bigger problem with Zika virus infection is that it has been linked to birth defects including microcephaly (literally, small brain) in babies born to pregnant women infected with Zika virus.  Last year, there was an outbreak of Zika virus in Brazil along with an unusually large number of babies born with microcephaly, and Zika continues to spread throughout Central and South America (see map, below).  Because it’s vector (that Uber described above, the mosquito) is notoriously hard to contain, Zika virus outbreaks are not likely to go away any time soon.

So, what should you know and what can you do?

1.  First and foremost, if you live in a purple area on this map, take precautions to prevent mosquito bites.   Notably, use insect repellent, wear clothing that covers exposed skin, and stay and sleep indoors.
2. No cases of Zika have been reported yet in the U.S. that have not been in a traveler returning from a purple area.  That is, right now people in the U.S. aren’t getting infected.  However, much like how West Nile virus, Eastern Equine Encephalitis virus, and more recently Chikungunya virus made their way to the U.S, infected travelers may pass the virus to local mosquitoes, which can then infect other people.  You can be sure that the Centers for Disease Control and Prevention (CDC) will be keeping a close eye on Zika virus infections, particularly in the southern U.S. right now, and all over the U.S. come the spring and summer months.
3. There is no vaccine or treatment for Zika virus infection.  If you have Zika, get plenty of fluids and rest.  Importantly, the best thing you can do is to stay indoors, away from mosquitoes.  It’s not known how long Zika virus stays in the blood, but based on what we know about similar viruses, it’s likely to be about 1 week.  By staying away from mosquitoes, you can stop the transmission of the virus to others.
4. Because of the risks of microcephaly, if you are pregnant, the CDC suggests delaying travel to the purple areas in the map above, where Zika virus is present.  If you must travel, take precautions to prevent mosquito bites.
5. Public health authorities in 4 countries (Columbia, El Salvador, Equador, and Jamaica) have issued statements urging families to delay planned pregnancy.  It’s not clear whether these statements will impact pregnancy rates or incidence of microcephaly in these areas, nor what social ramifications may arise if they do, but it’s likely to be a hotly debated global issue for 2016.

For more information, please see the CDC Zika virus page