Insect Parasite
Insect Parasite is a hidden infection status effect. It can be detected by the Blood Analysis bionic, but cannot be cured until it goes off by itself.
This effect is given by a dermatik's special attack. The attack can be dodged (if dodge roll is higher than 5d10) or parried (high enough melee and unarmed skills), or absorbed by armor (cut protection => 2). Having a cattle tail makes swatting away the attack easier. Successfully swatting away a dermatik attack can damage the dermatik, or make it stumble. Dermatiks will not try to infect you with more parasites if you are already incubating some. You also will not be infected if you have acid blood or parasite immune mutations.
Insect Parasite will cause Bugs Under Skin for 1200 turns (2 hours). Chance starts as "480.04% per turn, and raising until reaches its peak near fourth hour (2399 turn), where it becomes inevitable 100%, and then fades to 0.1(6)%.
After four in-game hours (2400 turns) there will be 0.04% chance to vomit per turn.
The infection ends after twenty-four hours (14400 turns) with the spawning of larvae, which will take away 600 movement points. Each larva upon eruption will hurt random body part for 4-8 damage (33% for one of arms, 33% for one of legs, else torso). The amount of larvae depends on strength, with the max of 6, which always will be reached when character's strength higher than 10. There is 33% chance that larvae will be friendly.
Bugs Under Skin
This state of the effect decreases the character's strength by 1, intelligence by 2, and adds chance based on intelligence ( one in 10 + 40*[int] ) to start scratching yourself. Scratching interrupts current activity, hurts whichever part is infested by 1 point, and costs 150 movement points.
Formication is also one of attack-effects of the Schizophrenic trait (duration of 600 turns, may stack) and can be removed with thorazine in this case.