How can a disease start to spread into humanity?
Diseases can be spread from person to person via viruses, bacteria, fungi, or parasites. Examples of diseases that are spread by each agent are listed below:
- Viruses: influenza
- Bacterial infections: strep throat or tuberculosis
- Fungal infection: Many skin diseases are fungal, such as ringworm or athlete's foot.
-Parasites: Malaria is caused by a parasite that is spread via mosquito bites. Other parasitic diseases can be spread through the feces of pets.
These diseases can be transmitted via the direct or indirect contact of organisms. Examples of how infection can be transmitted via direct contact are through cuts, saliva (such as when kissing), or other bodily fluids. Examples of indirect transmission of germs are via contaminated inanimate objects (doorknob, a table, etc), insect bites, or food contamination.