What causes infectious diseases? Do these spread from one person to another?
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 air, blood, insect food, water, and direct skin contact transmission.
Infectious diseases can be caused by microorganisms such as bacteria, viruses, parasites, or fungi. In our body live many microorganisms, most of them harmless or even necessary for the good functioning of our organism.
Causing agents of infectious diseases
How do infectious diseases spread?
Some microorganisms may cause various infectious diseases that can be passed from person to person. Other infectious diseases are transmitted by insects and other animals. The easiest way to get infected is by having direct contact with an infected human or animal.
The transmission can happen through direct contacts:
Infectious diseases can spread by indirect contact
Many of these microorganisms - bacteria, viruses, fungi, and parasites - can linger on objects including doorknobs, faucet handles, tabletops. Infectious diseases can also spread through contaminated water or food. This transmission allows germs to be passed to a number of people through a single source which can be a not properly cooked meat, not properly washed raw fruits or vegetables, not pasteurized juice fruits or milk, water, or ice cubes from an infected source.
Source: https://www.cedars-sinai.edu/