A cruise ship is being quarantined at a port in St. Lucia after it was discovered someone on board had measles.

Passengers are being kept on board because health officials don't want the disease to spread.

The boat is reportedly owned by the Church of Scientology, who did not comment on the matter.

Symptoms of the measles include rash, high fever, cough, runny nose and red, watery eyes. It can cause serious complications such as pneumonia and the swelling of the brain.

The Centers for Disease Control and Prevention says that cases of the measles in the United States have reached their highest peak in 25 years – with over 667 cases reported this year.