In May of last year, it was announced that Ebola, at one point the seemingly deadliest virus to date, was basically no longer a threat. Unfortunately, in that same month, the Pan American Health Organization (PAHO) reported an outbreak of Zika, a mosquito-borne virus, in Brazil -- and it has continued to spread.

Though not nearly as life-threatening as Ebola, this virus has already affected many, and is causing concerns for those traveling to infected countries and territories.

So before you travel and/or freak out, here are six things you need to know about the Zika virus.

1. The mosquito-borne virus was discovered in Africa, but it has spread over the past several months.

Brazil’s Sao Paulo has reported numerous cases.

Zika was first discovered in Africa in the 1950s. But it didn’t spread widely until 2014, when it reached the French Polynesia. In 2015, Zika made its way to South America, the Caribbean, and Central America. The largest recent outbreak was in Brazil in May 2015; reports indicate there have been over 3,000 related cases in the country.

2. Reports have even claimed cases in Europe, though we can't know how many.

It was announced today that a Danish citizen contracted the virus after visiting countries in Central and South America. Though this is apparently not Europe’s first reported case, the exact numbers will likely never be known: countries in the European Union are not required to report cases of Zika to the European Centre for Disease Prevention and Control (ECDC).

3. The U.S. CDC has issued an alert for travelers visiting 24 countries and territories.

Since the virus can cause birth defects in children born of infected women, the U.S. Center for Disease Control and Prevention (CDC) has issued a Level 2 Travel Alert for pregnant women visiting the following Zika-affected areas:

Puerto Rico is one of many popular destinations affected.

BrazilColombiaEl SalvadorFrench GuianaGuatemalaHaitiHondurasMartiniqueMexicoPanamaParaguaySuriname

Cape Verde is also an affected area.

VenezuelaPuerto RicoU.S. Virgin IslandsDominican RepublicBarbadosBoliviaEcuadorGuadeloupeSaint MartinGuyanaCape VerdeSamoa

4. Most travelers, even to these countries, should be fine.

Though there is no medication for Zika, it is a relatively mild sickness, generally lasting a week or less; there have been no reported deaths from the virus to date.

5. But all should practice caution, and look out for symptoms.

Still, it can cause serious birth defects in the children of infected mothers; Zika is linked to microcephaly birth defects, in which children are born with malformed or smaller heads and brains that can cause serious developmental delays. Health officials in infected El Salvador have gone so far as to advise all women to avoid pregnancy until 2018.

Researchers are also looking into a potential link between the virus and Guillain-Barre, a rare form of paralysis. Largely transmitted via a bite from the Aedes aegypti species of mosquito, Zika causes symptoms such as fever, rash, headache, joint pain, and muscle pain.

6. Airlines are offering refunds to some passengers with flights to infected areas.

Mexico City is a top travel destination for 2016, but it falls onto the CDC list of Zika-affected areas.

In response to the CDC travel alert, numerous airlines are offering free re-bookings and/or cancellations to pregnant women scheduled to travel to Zika-affected areas. Pregnant women with the appropriate doctors’ notices can receive full refunds from American Airlines for flights booked to San Salvador, San Pedro Sula and Tegucigalpa in Honduras, Panama City, and Guatemala City. British Airways is allowing pregnant passengers traveling to Sao Paulo and Rio de Janeiro in Brazil, Mexico City, or Cancun to change their reservations, free of charge.

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