Actinomyces viscosus endocarditis requiring aortic valve replacement. Journal   The Journal of infection. Citation   J Infect. 50(4):359-62 Publication date   2005 May Authors   Julian KG de Flesco L Clarke LE Parent LJ Investigators   Leslie J. Parent MeSH headings   Actinomyces viscosus Actinomycosis Aortic Valve Endocarditis, Bacterial MeSH qualifiers   isolation & purification surgery Abstract   We report a case of primary Actinomyces viscosus endocarditis, an unusual manifestation of actinomycosis, in a 43-year-old farmer with an indolent febrile illness. As has occurred in previous cases, diagnosis was delayed in part because blood isolates were misidentified. Months later when she required aortic valve and root replacement, histologic exam of the diseased valve revealed branching filamentous organisms and the original blood isolates were retrospectively confirmed to be Actinomyces viscosus.