I am not aware of that issue, but has something been reported as of late? It is a popular Backpacker/Surfer/Adventure/Need a beach fix and let your hair down kinda place, for a few decades. There may be random issues, but nothing to deter me from saying you would be fine if you follow the typical precautions.
Just so you know, the issue with SJDS for most is its touristy, a lot of gringos and you have to commute to the good beaches and surf breaks. Otherwise, if your headed to Leon, consider the beaches near there, the where the locals from Leon go.
Ometepe is a very relaxing islands that is magical and detached from the mainland. Corn Islands would be a 5 day side trip, but few make it there, though safety at night can be an issue if solo, male or female. But i Have not been there, just repeating what past posters have reported...do your homework and know where not to go.
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