I would also include the information about when mosquito season is in your profile and/or when you respond to a guest's booking. I'd just say something like: If you've never been to this area at this time of year be aware that we are in mosquito season. I provide lotions and sprays to help keep them away and keep the inside of the house free of them by keeping doors and windows shut.
I feel like guests are less likely to ding you if they know in advance what to expect (the good and the bad). And that you have a plan to help them be more comfortable.
Obviously staying at another Airbnb in the same area would still have the same mosquitos so I don't see that informing them would risk any bookings. I think they'd appreciate the heads up.
Good luck!