The Four Main Types of Infectious Disease
Infectious diseases are caused by microorganisms, such as viruses, bacteria, fungi, or parasites, spreading from person to person. They can also be transmitted through exposed food or water, contact with animals, or contaminated surfaces. These diseases can be mild, such as the common cold, or more serious, such as pneumonia.
There are four main types:
Bacterial infectious diseases are caused by bacteria, single-celled microorganisms that can multiply quickly. They are often treated with antibiotics.
Viral infectious diseases are caused by viruses, tiny infectious particles that invade living cells and replicate inside them. Viruses are usually spread through coughing and sneezing or contact with contaminated surfaces. They can sometimes be treated with antiviral medicine.
Fungal infectious diseases are caused by fungi, multicellular organisms that can live on dead or decaying matter. Fungi can also cause infections in people with weakened immune systems. Treatment for these diseases usually involves antifungal medications.
Parasitic infectious diseases are caused by parasites, tiny organisms that live on or inside other organisms (hosts) and rely on them for food and shelter. Some parasites can cause severe illnesses in humans. Treatments for parasitic diseases vary depending on the type of parasite involved.