4 countries added to growing list of Zika virus travel advisories

The Centers for Disease Control is warning pregnant women to avoid travel to four more countries because of Zika virus.

On Monday, the CDC added American Samoa, Costa Rica, Curaçao and Nicaragua to the advisories.

Zika virus has been linked to a sharp increase in birth defects, including a particularly devastating condition known as microcephaly. In addition to birth abnormalities, the Zika virus has also been tied to an uptick in adult neurological disorders such as Guillain-Barré syndrome, which can cause paralysis.

"Some travelers to areas with ongoing Zika virus transmission will become infected while traveling but will not become sick until they return home," the CDC said in a statement. "Some people who are infected do not have any symptoms."

The countries and territories already on the list: Barbados, Bolivia, Cape Verde, Colombia, Ecuador, El Salvador, French Guiana, Guadeloupe, Guatemala, Guyana, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Saint Martin, Suriname, Venezuela, the Commonwealth of Puerto Rico and Samoa.

The only Central American country not on the list yet is Belize.

While the advisories are targeted toward women who are pregnant or trying to get pregnant, the effect of the warning could be much larger. The World Health Organization (WHO) announced on Monday that the outbreak is now an international "public health emergency." 

Travel risk management company On Call International ran a Google Consumer Survey of U.S. adults, and 64% or respondents said they would cancel their trip to affected countries amid the outbreak.

Only 32% of women who responded to the survey said they would proceed with their travel plans.

Andrew Freedman contributed to this report.

Have something to add to this story? Share it in the comments.