Here are some ways for a disease to get inside a person:
VIA THE LUNGS.
Diseases attack the vulnerable tissues in the lungs, or pass quickly into the bloodstream.
VIA A WOUND or A BITE.
Diseases infect a wound and get quickly into the bloodstream.
VIA THE MOUTH.
Diseases enter the body in contaminated food or water, then enter the body through the vulnerable tissues in the gut.
VIA BLOOD OR SEX.
Congratulations! Youve gotten your virulent self inside your target host. Youre finding big fat host cells and starting to reproduce.
But wait! The person has started to feel symptoms and theyve gone to see their doctor.
Now you come up against the fourth barrier: medical response. They're gonna try everything they can think of to stop you from reproducing in the human body - antibiotics, medicines, treatments.
Do you have some ideas how to pass this barrier?
Jot down all the ideas you can think of, then continue.