Fast-spreading norovirus is often to blame for similar symptoms sweeping closed quarters like those on cruise ships, but a determination will likely have to wait until samples are tested in a lab. Diaz said special cleaning products and disinfectants that are proven to kill norovirus are being used to clean the ship.
In a Sunday statement, Beverly Nicholson-Doty, the U.S. Virgin Islands' tourism commissioner, said the territory was grateful for the CDC's "quick response" and St. Thomas was ready to welcome ship passengers cleared to disembark.
On Friday, an Explorer of the Seas passenger named Arnee Dodd tweeted that she had fallen ill aboard the ship and was quarantined with the other sick people. The Connecticut woman wrote that ship employees "put a lock down on food & are constantly cleaning everything."
It was not clear if any passengers were still being quarantined Sunday.
The ship's next scheduled stop is the Dutch Caribbean country of St. Maarten.
David McFadden on Twitter: http://twitter.com/dmcfadd