Major airlines have announced that they will allow customers concerned about the Zika virus to cancel or postpone their trips if they are ticketed to fly to areas affected by the infectious virus, USA Today reported Tuesday. Just last week, the U.S. Centers for Disease Control and Prevention (CDC) issued a travel warning for more destinations, largely in the Americas, as information continues to emerge about the dangers of the mosquito-borne virus. 

United Airlines claimed its policy will include to travel to all areas mentioned in the CDC alert, which now includes Puerto Rico, Brazil, Colombia, El Salvador, French Guiana, Guatemala, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Suriname, Venezuela, Barbados, Bolivia, Ecuador, Guadeloupe, Saint Martin, Guyana, Cape Verde and Samoa. Late Tuesday, the CDC added the U.S. Virgin Islands and the Dominican Republic to that list. It was unclear whether the cancelation policy would cover the two additional locations. 

“We are offering customers who are traveling to the affected regions the opportunity to rebook at a later date or receive a full refund,” United Airlines spokesman Charles Hobart said in a statement to USA Today on Tuesday.

American Airlines' policy, which was implemented Monday, will allow customers to receive a refund if they provide a doctor's note stating they are unable to travel to one of four cities due pregnancy. The four cities included in American's policy are San Pedro Sula and Tegucigalpa, Honduras as well as Panama City, Panama and Guatemala City, USA Today reported.  

Grupo LATAM, the largest airline in Latin America, also said it will be waiving cancelation and flight-change fees for pregnant customers ticketed for Brazil, Colombia, El Salvador, Guatemala, French Guiana, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Puerto Rico, Suriname and Venezuela. 

"In order to be eligible for these options, the pregnant passenger must submit a medical statement from a doctor confirming the weeks of gestation," Grupo LATAM told Mashable.

Officials in Brazil are investigating more than 3,500 cases of microcephaly, a birth defect in newborns, that were reported between October and January. While the exact correlation between a Zika infection and microcephaly is unclear, officials believe that pregnant women who are bitten by infected mosquitoes may be transmitting the virus to their fetuses through the placenta.

“Pregnant women in any trimester should consider postponing travel to the areas where Zika virus transmission is ongoing," the CDC said.