There are currently 57 countries and territories with direct flights to countries where the Zika virus is being actively transmitted, according to a Quartz analysis of flight schedules from PlaneStats.com, and information from the US Centers for Disease Control and Prevention.

Zika has “exploded” in the Americas, according to the World Health Organization. The mosquito-transmitted disease is being actively transmitted in 24 countries and territories. Typically Zika leads to a mild fever in adults, but recently it has been associated with microcephaly, a birth defect that causes infants to be born with shrunken heads and incompletely developed brains, and Guillain-Barré syndrome, a rare neurological condition that causes temporary paralysis.

The virus is thought to only be transmitted by certain mosquitos after it bites an infected individual.

Currently, many of the places one flight away from the virus have seasonal weather that is inhospitable to the mosquitos that carry the virus (though there is some doubt about which types of mosquitoes are capable of transmission). So the travelers flying these routes are at a low risk of spreading the virus—at least until warmer temperatures during the northern hemisphere’s spring and summer.