Research overview: the historical recognition of FIP

Feline infectious peritonitis was first described as a distinct clinical and pathologic entity in the 1960s, before its coronavirus etiology was understood, with early reports characterizing the fibrinous peritonitis, effusions, and granulomatous lesions that define the disease. Subsequent decades established the viral cause, the relationship to ubiquitous enteric coronavirus, and the immunopathogenesis. This overview compiles the historical literature rather than one citation, describing how FIP was distinguished from other feline diseases, how recognition of feline coronavirus reframed it as an in-host complication of common infection, and why its long reputation as an incurable, heartbreaking disease set the stage for the dramatic impact of the antiviral breakthroughs that arrived more than half a century after its first description.