The ship is expected to arrive in Willemstad, Curacao, around daybreak Saturday, according to officials on the island and Albert Elens, managing director of Maduro Shipping, the Freewinds' agent in Curacao.
When it arrives, a team of local health officials will assess those on board before consulting with international health agencies on a disembarkation plan, the head of the Epidemiology and Research Unit at Curacao’s Ministry of Health, Izzy Gerstenbluth, told ABC News. The vast majority of those aboard the ship were crew members, including the woman who had tested positive for measles, Gerstenbluth, said.
The ship is expected to arrive around 3:45 a.m. Saturday, according to the Curacao Ports Authority. There are about 300 crew members and passengers on board, according to Elens.
On Tuesday, Dr. Merlene Fredericks-James, chief medical officer in St. Lucia, announced that a cruise ship had docked on the island and was being quarantined as health officials investigated a possible case of measles aboard the vessel. By Wednesday, St. Lucia police had confirmed the ship was the Freewinds and belonged to the Church of Scientology.
The Freewinds website describes the ship as "a religious retreat that marks for Scientologists the pinnacle of their journey to total spiritual freedom."
St. Lucia's Department of Health and Wellness said in a statement Thursday that its investigation aboard the ship had confirmed that one person had measles.
Gerstenbluth, who is a public health physician and epidemiologist, said he had been in touch daily with the ship's doctor, who originally thought the woman with measles had a cold. The woman had been in Europe "for a while" before boarding the ship on April 17, he said. The ship's doctor said she exhibited cold symptoms on April 22, developed a fever the next day, and three days later developed a rash, according to Gerstenbluth, who said the ship's doctor isolated the woman from the start.
When the ship stopped in Aruba on Monday, the ship's doctor took a blood sample that, two days later, tested positive for measles, Gerstenbluth said. At that point, Gerstenbluth consulted with the ship's doctor about isolating the woman and taking an inventory of those on the ship, as authorities in St. Lucia -- the ship's next destination -- were notified.
"On the ship, you have to be a bit more broad-minded and consider the entire ship to have had contact," Gerstenbluth said.
In St. Lucia, both police and the health ministry said that no one had been allowed on or off the ship until it departed Thursday night over fears that others on the ship may be infected.
"Measles, we know, is a highly infectious disease. So because of the risk of potential infection, not just from the confirmed measles case but from other persons who may be on the boat at the time, we thought it prudent to make a decision not to allow anyone to disembark," Fredericks-James said. "The Ministry of Health continues to work with all authorities."
St. Lucian authorities did not disclose any information about the woman and Gerstenbluth said he did not know her nationality.
The woman, as well as other crew and passengers, were "stable" and under surveillance by the ship's doctor, the St. Lucian health ministry said Thursday.
"Continued surveillance is necessary as the incubation period for measles ranges from 10 to 12 days, before symptoms in exposed persons occur," the health ministry said in a statement.
The ministry said it had also provided 100 doses of the measles vaccine, free of charge, at the request of the ship's doctor.
When Curacao authorities investigate Saturday, they will also seek out information about people who had been in contact with the infected woman in the days before she tested positive for measles and who had already left the ship, Gerstenbluth said.
"That’s another group that we’re trying to make an inventory of," he said. "Who are these people, where do they live, and where do they come from?"
Gerstenbluth said those still aboard who had been previously vaccinated or who had previously had the measles would likely be allowed to disembark after authorities investigate Saturday.
Before the ship's departure from St. Lucia Thursday night, authorities there were in contact with their counterparts in Curacao and shared information with them, St. Lucia's health ministry said. It also said local officers who boarded the ship while it was in St. Lucia would continue to be monitored. St. Lucia confirmed Friday that the ship had departed Thursday night "for its home port in the Dutch Caribbean."
An adviser to Dominica's prime minister told ABC News Thursday that the ship had intended to come to Dominica for an event but that the event had since been canceled and the ship was not coming.
The ship was scheduled to depart to Aruba on Sunday night but Elens said the health-inspection team and Aruban officials would determine whether the ship would stay in Curacao or continue onward as planned.
"[We] will have to wait and see," he said.
The Church of Scientology has not responded to a request for comment from ABC News.