The world's largest cruise ship, Freedom of the Seas, returned to Miami on Dec. 3rd with more than 380 passengers and crew were sickened by what was believed to be the norovirus, according to Royal Caribbean Cruise Line officials.

The outbreak struck Freedom during a week-long cruise to the western Caribbean, and was likely brought aboard on Nov. 26th by an ill guest, according to the company. The norovirus, spread by contact, can quickly sweep through enclosed areas like cruise ships.

The outbreak on Freedom comes only a couple of weeks after more than 700 passengers and crew members were sickened during a trans-Atlantic repositioning sailing by the Carnival Cruise Lines ship Carnival Liberty from Italy to Fort Lauderdale.

The norovirus, which is characterized by stomach flu-like symptoms, affects about 23 million Americans annually, making it the second most common illness after the common cold, according to the U.S. Centers for Disease Control.

Freedom of the Seas and the Carnival Liberty are the two line's newest cruise ships, suggesting that passengers on older ships are no more at risk than on the very newest.

The ill passengers on Freedom of the Seas received over-the-counter medication, and crew members sanitized frequently touched surfaces such as railings, door handles and elevator buttons after the outbreak began.