Fleas and ticks in the tropics are a major problem. Even with Frontline Plus they can still develop tick fever. If you are thinking of bringing dogs to the tropics at a minimum they should already be on heartworm medication for a time, and also Frontline or similar. Then, with regular bathing and diligence in looking for ticks and removing promptly they may escape major problems. If the vet only visits Caulker every 2 weeks, emergency care would require at least a boat ride.