There were about 300 people aboard the ship, according to Saint Lucia authorities, which said they provided 100 doses of measles vaccine at no cost.
A Church of Scientology cruise ship quarantined by the Caribbean nation of St. Lucia for measles is due to arrive on Saturday back at its home port on the island of Curacao, where it will face similar restrictions, a top health official there said. The ship is scheduled to arrive early Saturday in Curacao, where it is normally docked when not in use.
On Thursday, the ship's doctor requested 100 doses of the measles vaccine, according to a statement from the St. Lucia Department of Health and Wellness, "and this is now being provided from our supplies, at no cost".
Gerstenbluth said the infected crew member had travelled to Europe and rejoined the ship on April 17, then reported feeling ill on April 22.
An official with St. Lucia's Marine Police identified the ship as the Freewinds.
The Church of Scientology operates the ship and calls Curacao its home port. According to the church's website, the ship is a religious retreat for Scientology members.
Though Scientology takes a well-known stance in opposition to psychiatric medication, the church does not oppose standard medical treatment for physical illness and injury. The measles virus is highly contagious and can cause blindness, deafness, brain damage or death. They said proof is required, and that people who do not comply will be vaccinated immediately.
The number of measles cases in the United States has reached a 25-year peak with more than 700 people diagnosed as of this week, part of an worldwide resurgence in the disease.
That includes the largest outbreaks in Orthodox Jewish communities in and around New York City.
Incubation can last up to 21 days after exposure, with infected individuals most contagious from four days before the onset of tell-tale measles rash - while the person is experiencing cold-like symptoms - to four days after the rash appears. If they have already caught the disease, the vaccine should reduce the severity.
Some children complain of disliking bright lights or develop white spots with red backgrounds on their tongue.