WASHINGTON (AP) — The United States is warning of the risk of Zika virus in Cuba just as President Barack Obama heads to the country.

The Centers for Disease Control and Prevention says it's adding Cuba to its travel notice for Zika. The notice warns travelers they are at risk of contracting the virus.

Zika is spread though bites from a specific mosquito and is believed to carry particular risk for birth defects. The CDC advises pregnant women not to travel to places with Zika.

Obama heads to Cuba on Sunday on a three-day trip. It's the first trip to the country by a sitting U.S. president in nearly 90 years.

The Obama administration says the virus hasn't been a factor in Obama's travel decisions and isn't expected to be in the future.