Infectious diseases are caused by pathogenic microorganisms, such as bacteria, viruses, parasites or fungi; the diseases can be spread, directly or indirectly, from one person to another. Zoonotic diseases are infectious diseases of animals that can cause disease when transmitted to humans.
A variety of infectious agents are difficult to control. Genetically modified cells can be produced that specifically target these organisms or cells infected with them to enhance weak body defenses and eliminate the infections. Pathogen-specific CARs can be developed to eliminate drug-resistant or difficult to treat infectious agents.