When packing for a jungle expedition, think light. Not only will this save wear and tear on your back and feet, but some jungle expedition trails actually have weight limits on what hikers can bring.
Probably the most important item in jungle travel is water. A long day hike could require as much as 6 to 8 liters per person to stay hydrated. Some jungle hikers bring portable water purification gear, but this requires you to scramble down to ponds or streams, and then climb back up to the trail again. Iodine tablets can also purify water found in the jungle, but it leaves a nasty taste and prolonged use is not good for you.
* Ask your jungle touring company what they do to provide water during your hike so you can really prepare.