What is the cause for infectious diseases? Do they spread from one person to another?
Infectious diseases are caused by pathogens such as bacteria, virus, parasites, and some kinds of fungi.
These diseases range from common infections such as cold, flu, sore throat, bronchitis, laryngitis to more lethal illnesses such as AIDS. Viral infections are more contagious when compared to bacterial infections. Based on the disease-causing microorganism, infectious diseases spread through airborne, blood-borne, insect-borne, food borne, water borne, and direct skin contact transmission.