While most tours and adventure activities are relatively safe, serious risks may be involved for careless participants. However, a little common sense is all you need. Risks most often occur when people try to extend their efforts beyond their physical capabilities. Know your limits. The sometimes-extreme heat and wild temperature shifts found in Nicaragua and El Salvador can take their toll on a body rather quickly. Heavy downpours can occur at any time, thus dropping the temperatures and making rainforest paths beyond slippery. Rain gear is essential in this environment, as is sunscreen. Have dry clothes ready, too, for the end of your excursion.
When hiking through the jungle -- there's real, genuine, wild jungle here -- and the backcountry, there are general precautions to take. Chances are you will not see many snakes, if any, but if you do, don't encourage one to bite you. Stay calm, don't make any sudden movements, and don't touch it. If you swim in lagoons and near mangrove forests, just remember that healthy populations of critters -- from otters to caimans -- inhabit most of them. Ask locals where it is safe to swim. Also, avoid swimming in major rivers unless a guide or local operator can vouch for their safety. Be careful with ocean currents, as well, especially along the Pacific coast.
Bugs and bug bites will probably be your greatest health concern in the wet and humid wilderness, and even they aren't as big of a problem as you might expect. Even on the Atlantic coast, there aren't that many mosquitoes. Mostly, bugs are an inconvenience, although mosquitoes can carry malaria or dengue. Strong repellent and proper clothing minimize both the danger and the inconvenience; you might also want to bring along some cortisone or Benadryl cream to soothe itching. At some beaches, you'll probably be bitten by pirujas (sand fleas or no-see-ums). These nearly invisible insects leave an irritating welt. Try not to scratch because this can lead to open sores and infections. Pirujas are most active at sunrise and sunset, so you might want to cover up or avoid the beaches at these times.
The slogan "Leave nothing but footprints; take nothing but memories" certainly applies here, though if you can avoid leaving footprints, even better. Much of the Nicaraguan wilderness holds an array of rare and little-known flora and fauna, and some of it is highly endangered and endemic to the specific mountain or tract of forest. Do not cut or uproot plants or flowers. Pack out everything you pack in, and please do not litter. Take photos and nothing else.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.