The direct fluorescent antibody test (DFA) is most frequently used to routine diagnose of rabies. This test can be performed on brain tissue of animals suspected of being rabid. The rapid and accurate laboratory diagnosis of rabies infections in animals is essential for timely administration of postexposure prophylaxis. Within a few hours, a diagnostic laboratory can determine whether or not an animal is rabid and inform the responsible medical personnel. The laboratory results may save a patient from unnecessary physical and psychological trauma, if the animal is not rabid. All rabies laboratories in the Yugoslavia (3) perform this test on animals suspected of having rabies.
The DFA test is based on the principle that an animal infected by rabies virus will have rabies virus antigen present in its tissue. Because rabies is present in nervous tissue (and not blood like many other viruses) the ideal tissue to test for the presence of rabies antigen is brain. The most important part of a DFA test is flouresecently-