I think it's not a bad idea to wear repellent. Mosquitos can spread Chikungunya, Malaria, Dengue fever and West Nile Virus (Some of those can be found in the Bahamas). It takes two seconds to put repellent on. Better be safe than sorry.
they sell off onboard. the only cruise i've ever been concerned about it was on alaska - apparently there are ginormous mosquitos there, but we didn't encounter any. unless i were doing some wild, deep jungle excursion, i wouldn't even give it two thoughts. people get more concerned about dead lice or fleas or whatever it is on castaway cay. we've luckily never encountered whatever that is!
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