Pathogens, such as viruses and bacteria, cause infectious diseases. They can be contracted from other individuals, the environment, animal contact, or insect bites, among other things. Researchers hope to learn more about how these microbes interact with immune cells in order to develop vaccines and treatments for infectious disorders. Antibiotics can be used to treat a variety of infectious disorders (specifically diseases caused by bacteria). Antiviral drugs can be used to treat diseases caused by viruses, and antifungal medications can be used to treat diseases caused by fungi. Immunology is a branch of biomedical sciences that studies the immune system in all multicellular organisms. It is concerned with the organism's defense mechanisms, which include all physical, chemical, and biological features that aid in the organism's resistance to invading organisms, materials, and other threats. Immunology is concerned with the immune system's physiological functioning in both health and sickness, as well as immune system abnormalities in immunological disorders.