Postmortem diagnosis of rabies in animals and humans
Fluorescent antibody testing is potentially applicable to any antigen-antibody reaction. a labeled immune globulin is employed as a source of antibodies used to detect the presence of rabies antigen in apecimens.
A positive FA Test is indicated by a green fluorescent staining of rabies antigen in test smears.( Rabies antigens reacting with specific antibody tagged with fluorescein isothiocyanate (FITC) under filtered ultraviolet/blue light microscopy appear as brightly coloured apple-green particles or bodies against a dark or counterstained background. )
The diagnosis of rabies by the FA Test was reported to be 99.4 % accurate, while the mouse inoculation test and Sellers stain for the detection of Negri bodies were 98.3 and 65.8 % respectively
( Johnson,H.W., and R.W.Emmons.1980 )