Get some permethrin to pre-treat your clothes from insects. Well worth it. As for nylon clothing, it is extremely uncomfortable in a hot/humid environment. A good choice would be a light, loose fitting cotton shirt and loose fitting cotton/poly trousers. Shorts should not be worn if hiking in the forest/jungle, too many things that stick you, sting you or potentially bite you.

Water bottles are more durable and cheaper than a Camelbak and also easier to use with a water filter. Filter all water.

Look up a doctor or clinic that specializes in travel medicines, they can get you the right immunizations, make the right entries on an international shot record and make other recommendations of a preventative nature for the specific region you are travelling to.

Considered Costa Rica? Could be a bit safer!

On a trip some years ago to Puerto Rico (A U.S. Territory) some of our companions were from US Customs and they were at a beach outside of San Juan and a group of nasties got between them and their gear. They lost weapons, ID and their wallets with pretty much everything else.
Awareness, awareness, awareness. Avoidance as well. Good luck!