nidus

Nidus is a noun borrowed from Latin meaning nest or breeding place. In medical and scientific usage, nidus refers to the focus, source, or reservoir from which a disease or infection originates or persists. The term emphasizes that the problem is anchored at a specific site rather than being diffuse throughout the body.

In infectious diseases, a nidus can be a location or object that harbors pathogens—such as necrotic tissue, a foreign body, or a chronic lesion—that sustains infection or allows re-seeding of pathogens to other sites. Examples include a nidus of infection in chronic osteomyelitis or a primary nidus that seeds a brain abscess. In some contexts, removal of the nidus is necessary to cure the condition.

Diagnosis and treatment: Identifying and eliminating the nidus—through surgical debridement, removal of a foreign body, or targeted therapy—along with appropriate antimicrobial therapy, is often required to resolve the infection and prevent recurrence.

Other uses: While most common in medicine, nidus can also be used more generally to denote a center or focal point of an activity, such as a parasite reservoir or a site of disease persistence, in non-clinical discussions.

See also: focus of infection, septic focus.