"The jungle is not a comfortable place" is something our guide kept repeating. The rainforest has all kinds of biting and scratching things that can cause discomfort and even death!
1. Before you leave home, make sure you have all of your shots and medications. Yellow Fever, Dengue Fever and Malaria are all things you don't want to get. See a travel medicine doctor for the appropriate treatment (immunizations for Yellow Fever), pills (prophylaxis) for malaria and avoidance for Dengue.
2. If venturing out into the rain forest - have appropirate clothing. Knee-high rubber boots, long sleeved shirt and long pants are a must. A comfortable hat and sunglasses are also high on my hit lits. Leeches are prevelent in the Sukai area - buy leech socks in Sandakan before heading off to any of the rain forest lodges.
3. Insect replellent - bring lots. Better too much than too little. Use ones that have at least 30% DEET.
4. Bring lots of water - dehydration in the head of the rainforest is no fun at all.
Being very damp, there is a big danger from leeches in this area if you are exploring the forests or the river.
I don't know how I managed to get a leech on my back, being on a boat, but I must have brushed against a leaf or a branch.
You don't feel anything most times. Unless they stick in your foot or another sensitive place. Mostly the first you know about having a leech attach to you is the big soggy patch of blood seeping through your clothes, and when you manage to get it off, it just bleeds for hours.
If you make sure no skin is exposed you are less likely to attract leeches. Tuck trousers into socks, tuck shirt into trousers and be careful where you put your hands.
if one does get through - it's messy, mostly painless, inconvenient, but not dangerous as the probe contains antiseptic. Could be worse............