| _ DISEASE _ | Caused by _ | Usually _ spread by | Prevalence __ in U.S.A. | Prevalence in poor countries |
| Common cold | virus | droplets, fluids, contact | common | common |
| Influenza | virus | contact, airborne | common | common |
| Polio | virus | water | rare | common in some |
| Hepatitis | virus | feces, food, body fluids | common | common |
| Mononucleosis | virus (EBV) | contact | common | common |
| Herpes, shingles, chicken pox | virus | contact, droplets, body fluids | common | common |
| Smallpox | virus | contact | eradicated worldwide in 1977 | |
| Measles | virus | droplets, contact | uncommon | common |
| Rubella (German measles) | virus | droplets, contact | uncommon | common |
| Mumps | virus | droplets, contact | uncommon | common |
| Rabies | virus | animal bites | uncommon | common |
| Warts | virus (HPV) | contact | common | common |
| HIV/AIDS | virus (HIV) | body fluids | uncommon | common |
| Sinus infection | bacteria | airborne | common | common |
| Food poisoning (Salmonella, Staphylococcus) | bacteria | food, also body fluids | common | common |
| Strep throat | bacteria | airborne, contact | common | common |
| Typhoid fever | bacteria | food, water, etc. | uncommon | common in some |
| Tuberculosis | bacteria | multiple routes | rare but resurgent | common in places |
| Lyme disease | bacteria | tick vectors | common in NE | common in some |
| Botulism | bacteria | food | uncommon | sporadic |
| Tetanus | bacteria | unclean wounds | uncommon | common |
| Cholera | bacteria | water | when disasters disrupt drinking water supplies | |
| Periodontal disease | bacteria | body fluids | very common | very common |
| Gonorrhea | bacteria | sexual contact | resurgent | resurgent |
| Chlamydia | bacteria-like(*) | sexual contact | very common | very common |
| Malaria | protozoan | mosquito vectors | rare | common |
| Amoebic dysentery | protozoan | water or feces | uncommon | common |
| Trypanosomiasis (incl. African sleeping sickness) | protozoan | insect vectors | very rare | common |
| Toxoplasmosis | protozoan | cat litter | common | common |
| Trichomoniasis | protozoan | sexual contact, body fluids | common | common |
| Candida yeast infection | fungus | sexual contact, body fluids | very common | very common |
| Schistosomiasis & other flukes | parasitic worms | mostly water | rare | very common |
| Tapeworms | parasitic worm | undercooked meat | occasional | common |
| Roundworms (**) | parasitic worms | soil, feces, meat | occasional | common, esp. tropics |