There are a couple of news stories here and here talking about a man on an Australian cruise who died of meningococcal disease.
The death, occurring a few years back, has prompted some changes to be made in cruise policy, notably that authorities must be notified, especially interstate health authorities to the risk posed to other passengers.
It sounds intuitive that cruise passengers should be notified of a potentially transmittable (and fatal) disease like this, but cross-jurisdictional policies can often be muddled and not require such notification when crossing international waters. Hopefully that policy will be mended.