The main routes to spread infection include:

• Airborne spread: Germs travel through the air in small droplets or tiny aerosol particles when an infected person talks, coughs, or sneezes. These can be breathed in by others nearby.
• Droplet spread: Larger droplets from coughs or sneezes travel short distances and can infect others nearby.
• Contact spread: Germs spread by touching infected skin or mucous membranes or through contact with contaminated surfaces (fomites) like toys, door handles, or bedding.
• Faeco-oral spread: Germs from feces get into the mouth, often via contaminated hands, food, or water.
• Spread through blood or body fluids, including urine, saliva, semen, or vaginal secretions.

Germs can spread directly person-to-person or indirectly through contaminated environments. Entry points to the body include the mouth, respiratory tract, eyes, genitals, and broken skin. Some infections can spread through several different routes simultaneously.