Communicable Diseases

They are caused by infectious agents or the toxins they produce. Transmission can occur through direct or indirect spread from infected individuals, animals, vectors, or inanimate environmental sources.

The biological basis centers on host-pathogen interactions and the host immune response to infection. The grounding highlights innate and adaptive immunity, cytokine signaling, and cytokine storm as important mechanisms in some infectious diseases, along with the role of host gene expression and immune maturation across the lifespan.

Risk is increased by exposure to infected individuals, animals, vectors, or contaminated environmental sources. The grounding also supports increased susceptibility with immature immune function in infancy and declining immune function in old age, as well as impaired immunity associated with protein or amino acid deficiency.

Management is described at the level of diagnosis, drug therapy, and therapy rather than for a single disease entity. The grounding supports infectious-disease diagnosis using clinical metagenomics and treatment approaches that include antimicrobial or other drug therapy, with vaccines represented by COVID-19 vaccines and synthetic vaccine platforms in the literature.