0 a small area of the sea or other water in which there is a powerful, circular current of water that can pull objects down into its centre -- 漩渦
Users of the whirlpool spa on the deck were fewer than 10 a day.
The attack rate was 71 % (27\38) and 24 cases (83 %) used the whirlpool.
She had used neither pool nor spa except for the women's indoor spa and possibly also the whirlpool spa on the ship.
As media attention was focused on the whirlpool, it is possible that some of the non-responders did not visit the whirlpool area.
Disentangling the activities among the epidemiological cases who visited the whirlpool area showed that 23 of 24 cases had used both whirlpool and shower.
After adjusting for confounding factors, only the use of the whirlpool proved to be a risk factor.
Students and staff were battered from all sides, sometimes on top of the wave and sometimes struggling in eddies and whirlpools.
Visiting the whirlpool area, taking a shower or using the whirlpool or the sauna were the activities most associated with a high risk for infection.
