There are multiple ways an infective agent might enter the body. Infective agents can enter the body through the mouth and nose into the windpipe and lungs which is how illnesses such as coughs and colds and various airborne illnesses are spread into the respiratory tract. Infective agents can also enter the body through the stomach tract which is the stomach, intestines and mouth causing illness upon swallowing infected or contaminated foods for example. Infective agents can also enter the body through breaks in the skin such as cuts grazes, puncture wounds and insect bites. They can also enter the body through the urinary and reproductive systems causing illnesses such as Sexually Transmitted Diseases, HIV and AIDs.
