ORLANDO, Fla. — Millions of people travel in and out of Disney World, Universal Orlando, and SeaWorld Orlando every year. So with the coronavirus spreading to areas outside of China, Florida's theme parks are keeping a close eye on developments.

• Coronavirus, officially called COVID-19, has spread internationally
• Florida's economy depends on millions of travelers visiting state
• Theme parks are bracing for potential impacts from the virus

On Tuesday, top health officials with the Centers for Disease Control and Prevention warned that the coronavirus will almost certainly spread in the U.S. and that Americans need to prepare.

"It's not so much a question of if this will happen anymore, but more really a question of when it will happen — and how many people in this country will have severe illness," said Dr. Nancy Messonnier, director of CDC's National Center for Immunization and Respiratory Diseases, in a briefing.

As for Florida, where the tourism industry is an integral part of the economy, the virus's potential impact on travel is a major concern. Even though there have been no confirmed cases of the coronavirus in the state, the theme parks are monitoring developments closely.

"The health and safety of our guests and team members is our top priority," Universal Orlando spokeswoman Alyson Lundell said in a statement. "We are in contact with health officials and others in our industry and we are closely monitoring the situation."

During an earnings call Wednesday morning, SeaWorld CEO Serge Rivera said the company's parks haven't seen a noticeable impact to business from the virus. But a SeaWorld spokesperson said the company is in contact with health officials to ensure guests and employee safety.

"The health and safety of our guests, ambassadors and animals is our top priority, the spokesperson said in an email. "In matters pertaining to public health, our parks take direction from Florida Department of Health or other state agency and Centers for Disease Control (CDC). We employ rigorous sanitation standards across our parks."

"At this time no additional measures are currently prescribed for our location. However we will continue to collaborate with health officials, monitor the situation for changes and will act accordingly."

At Disney World, several employees who recently returned from a trip to Italy were told to stay home. A Disney spokesperson said the decision was "out of an abundance of caution" as there are no suspected cases of coronavirus at Disney.

So far, the virus officially known as COVID-19 has sickened about 80,000 people worldwide and has been responsible for more than 2,700 deaths. In the U.S., there have been 57 confirmed cases.