Doctors working in the maternity wards of Recife, Brazil, noticed a spike in late August 2015 in babies born with a medical condition known as microcephaly — a defect characterized by normal head construction up to the eyebrows but with little-to-no forehead or upper cranial formation. Since then, scientists discovered that the Zika virus, a pathogen carried by female mosquitos, is the likely cause.

More than 1 million people in 30 different countries have been affected, with the potential for more than 4 million cases by the end of 2016. The World Health Organization (WHO) has declared a public health emergency and has urged health ministers in many Latin American countries to promote a period for women to refrain from childbirth. With the 2016 Summer Olympics in Rio de Janeiro and the Roman Catholic Church’s influence as it pertains to birth control and abortion, the virus will likely affect the region’s economy.

What is Zika?

Zika, named after the Ugandan forest where the virus originated from, is a mosquito-transmitted illness that causes a brief flu-like illness in adults. But the virus is incredibly deadly to unborn babies and newborn children. Aedes mosquitos are powerful hosts for Zika, as they are abundant and actively seek other species for feeding purposes. While the mosquitoes originated on the African continent, the species can now be found on every continent except Antarctica.

When did Zika start?

In 1947, U.S. and European scientists studying a rhesus monkey for yellow fever unintentionally discovered Zika when blood samples from an infected monkey showed the unknown virus. The first true outbreak of the disease happened in 2007 in the Yap Islands in Micronesia, where there were 49 confirmed cases. There were only 14 documented cases of Zika before that.

What happens to an infected individual?

Although the virus has been fatal in rare cases, it is generally mild to the host and could be gone in less than a week with proper treatment. Unborn babies are the most at risk and only 20 percent of adults who contract the disease ever show signs of it. Symptoms include fever, joint pain, red eyes and rash.

Is sexual transmission possible?

Sexually transmitting Zika is possible, but scientists are still researching the extent to which sexual contact impacts the spread of the virus. Last week, medical authorities in Texas confirmed a traveler who had recently returned from Venezuela infected a sexual partner. Prior to this event, scientists had only seen such incidents on two occasions.

Is there a vaccine?

As of now, there is no known vaccine for Zika, but scientists have been working on creating one for the past two years. The recent spike in cases will likely jump-start more initiatives for a cure. The virus is generally harmless on its own in adults, and over-the-counter drugs can treat the symptoms.

What does this mean for travel?

Indefinite travel warnings have been issued by the United States for 20 countries at the epicenter of the virus’ spread. In particular, pregnant women are urged to refrain from travel that puts their unborn fetuses at risk. The Center for Disease Control and Prevention (CDC) recommends travelers take extra precautions, especially in preventing mosquito bites.