The coronavirus cluster detected on the Diamond Princess cruise ship is by far the biggest cluster of cases outside mainland China. (Photo: AFP/Philip Fong)

HONG KONG: Deadly viruses, chickenpox outbreaks and mass cases of the runs: Sometimes luxury cruise ship holidays are not the trips of a lifetime elderly passengers had hoped for.

Cruise-goers have fallen sick en masse in the past, their predicament on the high seas coming into sharp focus because the holidays can cost thousands of dollars and are often marketed as trips of a lifetime.