which of the following is best for ante-moem diagnosis of rabies?

Option 1-Anti Rabies antibodies in blood appear late and can also be present after vaccination. So detection of antibodies in CSF is more significant. Option 2: Direct fluorescent antibody test is the ideal method of antemoem diagnosis of rabies. Samples can be: Corneal impression smear is only 30% sensitive, mainly it is positive in late stage. Biopsy of hair follicle of base of neck is more sensitive and considered as the best sample for direct fluorescent antibody (DFA) test . (But it is not given in the options above.) Hence, the answer is Immunofluorescence of corneal impression. Option 3: The brain biopsy of the dead animal is the specimen of choice for postmoem diagnosis of rabies. A B fig:-Histopathological examination of central nervous system tissue from autopsy of a decedent with suspected rabies infection,. (A)showing neuronal cytoplasmic inclusions (Negri bodies) after hematoxylin and eosin staining. (B).rabies virus antigen (red) after immunohistochemical staining Negri body detection is postmoem method of diagnosis, however it may not be detected in 20% of the cases.