Many. Different insects spread different diseases, bacterial, viral, rickettsial and parasitic. Most common insects spreading diseases include mosquitos, ticks and fleas. Diseases spread by insect bites include malaria, dengue, yellow fever, lyme disease, rocky mountain spoted fever, typhus, relapsing fever, plague, west nile virus and many more.
Depends. Tick bites can carry diseases like rocky mountain spotted fever, lyme disease, & ehrlichiosis. Mosquito bites in many areas of the world can carry malaria, yellow fever, & a host of other diseases. Any insect bite can become secondarily infected with strep, staph, mrsa. If the bite area is swelling, getting redder, draining pus, hurting more, see a doc as soon as possible for evaluation & tx.