Routine laboratory tests do not assist in making the diagnosis. The cerebrospinal fluid shows nonspecific elevation of leukocytes and protein, as occurs in other viral encephalitides. Neutralizing antibodies appear during the symptomatic phase. In the past, a definitive diagnosis depended on finding Negri bodies in Ammon's horn, a hallmark of rabies infection. Circulating antibodies may be detected in unvaccinated persons as early as the sixth day of illness and usually appear within the first 2 weeks.
Prompt treatment is important.
Bites and scratches should be thoroughly washed with soap and water. The longer postexposure prophylaxis is delayed, the less likely it is to be effective. Human rabies immunoglobulin is the preferred preparation for passive immunization and is often given with HDCV during postexposure prophylaxis. Local or state public health officials should be consulted if questions arise about the need for rabies prophylaxis. At present, therapy for clinical rabies is entirely supportive and has been credited with saving the lives of a few people who had received rabies vaccine before the onset of illness.