Two luxurious cruise ships have been linked to a Legionnaires’ disease outbreak, with private hot tubs on cabins emerging as the apparently relaxing sources of bacteria that sent ten passengers to the hospital.

Between November 2022 and June 2024, a dozen joy-seeking passengers found themselves battling Legionnaires’ disease after unwittingly soaking in luxury hot tubs that doubled as bacterial breeding grounds. The Centers for Disease Control and Prevention reported that private hot tubs on these ships, with harmless-sounding water temperatures but a serious penchant for Legionella growth, have left ten hospitalized, marking the cruise industry's biggest Legionella outbreak since 2008. As cruise lines scramble to do damage control, they’ve now vowed to fill these hot tubs only upon request—a decision that might leave some guests feeling less ‘splashing luxury’ and more ‘bathtub bingo.’

The unfortunate truth is that hot tubs, those bubbly havens of relaxation and social mingling, can sometimes harbor unwanted guests. In this case, between November 2022 and June 2024, at least a dozen passengers on two different cruise lines had to face the reality that their enjoyment could come with an unexpected side of lung infection. This discovery was enough to make anyone rethink their next dip in the hot tub, especially since 10 of the 12 affected individuals found their cruise dream turned into a hospital visit.

How precisely did we arrive at such a troubling situation? The CDC's epidemiologists, equipped with not just clipboards but a willingness to delve into the steamy underbelly of cruise life, conducted extensive interviews and environmental assessments. What they uncovered was enough to send shivers down the spine of any hot tub enthusiast. Investigations revealed that the private hot tubs, which cruise lines market as a unique feature for a luxurious getaway, were the prime suspects in this aquatic investigation. Specifically, Legionella bacteria were identified in a shocking six out of ten hot tubs on the first vessel, and all eight hot tubs on the second one. It seems like when it came to the prizes for the worst hot tub in the cruise industry, that bacteria got the gold medal.

A deeper look into the circumstances revealed some alarming operating procedures for these hot tubs. The water temperature in these indoor water spas, which varied between a cozy 77°F and a sweltering 113°F, was rather fond of staying stagnant for multiple days. And, as luck would have it, this temperature range is just what the bacteria ordered for a thriving habitat. Unearthly organisms could hardly ask for better conditions to spread their hospitality luxuriously churned out in water—albeit, seriously uninviting if you happen to be a human.

As cruise lines work to reconcile their luxury image with these unexpected 'pool parties' gone wrong, they’ve taken measures to clean their act. Both companies have made the decision to only fill private hot tubs upon request from guests and drain them after each use. It's a bold pivot reminiscent of a bar that decides to only serve drinks on special occasions. The result? Less spontaneous soaking, and possibly a few disgruntled clients who weren’t ready to trade in ‘sipping champagne under the stars’ for ‘waiting for permission to take a bath.’

This situation begs the question, why were these private hot tubs not maintained with the same zeal as public ones? It seems that this oversight is rooted in the fact that private hot tubs don’t undergo the stringent maintenance protocols required for their public counterparts. One can imagine the conversations among the cruise staff—overworked and way too caffeinated—debating just how much cleaning is necessary for a relaxing experience. Spoiler: letting the bubbly sit a bit too long doesn’t fall into the high-caretaking category.

A bit of context here: while small amounts of Legionella are often found in all water supplies, the levels on these ships had apparently reached a threshold that could cause illness. The CDC stepped in decisively, stating that despite a few passengers also reporting other locations as potential exposure points, blissfully dipping their toes in those hot tubs aboard the ships was the common link for all. So next time someone gets ill after a cruise, it might be wise to not blame the food or the questionable entertainment offerings but give a side-eye towards the hot tubs instead.

As cruise lines grapple with what is, quite frankly, an embarrassing reality, one must remember this isn't just a small hiccup in nautical hospitality. The cruise industry's reputation took quite the wave since this was the biggest Legionnaires’ disease outbreak on cruises investigated by the CDC since 2008. It raises concerns for other cruise-goers: What does it take to keep one safe while sailing the seas? It turns out, more than just a sturdy life vest and a steady supply of sunscreen may make all the difference.

As remedies are put in place to prevent further incidents, potential passengers might want to consider their options before unwinding in the inviting bubbles of a private hot tub onboard. After all, one person's relaxing retreat could quickly transform into another's unplanned hospital visit. It’s a modern balancing act between seeking luxury and safeguarding against secret bacteria monsters lurking just beneath the surface. If one thing’s for sure, the next time guests book their cruise, the hot tub application will certainly come with a disclaimer to think twice before deciding between lounging or leaping into potential bacterial baths.