All substances take up the least amount of volume in their (1.) solid phase, a little more volume in their (2.) liquid phase, and the largest amount of volume in their (3.) gas phase. The closer atoms or molecules get to one another, the less volume is occupied by the substance that they comprise.
A large, retrospective series examining human bite wounds in children found that none of the bites manifesting as abrasions became infected, while the rate of infection was much higher in bite wounds that caused punctures or lacerations.
From mites to mosquitoes, a variety of bugs bite humans, creating itchy skin reactions that range in severity from a mild irritation to a nasty rash. Itching is one of the more common reactions to bug bites, generally brought about by foreign proteins present in the offending insect's saliva.