A crew member aboard a cruise ship used by the Church of Scientology tested positive for measles, causing the vessel’s occupants to be quarantined in the Caribbean since Monday, a report said.

The vessel and its roughly 300 passengers and crew members have been stuck on the “Freewinds” ship in the Caribbean port of St. Lucia after the confirmed case of the highly contagious disease, according to NBC News.

The infected female patient has been isolated and is in stable condition, according to St. Lucia’s chief medical officer Dr. Marlene Fredericks-James.

St. Lucia Coast Guard Sgt. Victor Theodore confirmed to the network that the cruise ship was the same as the one listed on the Church of Scientology’s website.

The ship is described on the church’s website as being used as a floating “religious retreat ministering the most advanced level of spiritual counseling in the Scientology religion.”

The ship is set to depart Thursday. The church couldn’t immediately be reached for comment.