Diagnosis of rabies in cattle: Comparison of clinico-pathological, immunohistochemical and immunofluorescence techniques

The present study was envisaged to compare the sensitivity of detection of rabies virus antigen by application of Fluorescent Antibody Technique on fresh impression smear (Direct-FAT) and that on formalin-fixed nervous tissue (Indirect-FAT), histopathology and immunohistochemistry (IHC) in cattle. A total of 15 cases of cattle suspected for rabies were presented to Teaching Veterinary Clinical complex and from various parts of Punjab. Out of 15 cases, 9 (60%) cases were positive by direct-FAT, indirect-FAT and IHC. On the basis of Negri body detection and histomorphological alterations, rabies was confirmed in 7 (46.6%) cases, thus histopathology revealed 77.77% sensitivity in comparison to direct- FAT. While indirect-FAT, and IHC revealed 100% sensitivity in comparison to direct-FAT. Percentage of neurons positive for Negri bodies by H & E and IHC were 37.11% and 73.88% and average number of Negri bodies detected per neuron by H&E and IHC were 1.56 and 2.97, respectively. Important clinical signs in rabid animals were anorexia, biting, bellowing, hyper-salivation andfrequent micturition. Thus, it is concluded that rabies detection in animals can be accomplished from formalin-fixed brain tissues, which offers same sensitivity as detection of rabies in impression smears.