Rapid Diagnosis of Viral Infections in the Central Nervous System

Abstract

Rapid diagnosis of viral infections in the central nervous system has become increasingly important. Antiviral treatment, prevention of spread of disease and differentiation from infections caused by agents sensitive to antibiotics may be the important consequences of a virus specific diagnosis gained early in the disease. The diagnosis can be obtained by detection of virus or viral antigen in the human specimen: herpes simplex virus by electron microscopy, immunofluorescence or immunosorbent assays in brain biopsies; rabies virus by immunofluorescence in corneal cells or skin and mucous membranes. The presence of measles or influenza antigens in nasopharyngeal secretions, shown by immunofluorescence or enzyme immunoassays, may diagnose an encephalitis caused by either of these viruses. Where suitable material is not available the detection of virus-specific IgM in a single serum specimen may be used for diagnosis. Mumps specific IgM activity is detected by enzyme-linked immunosorbent assay (ELISA) or indirect immunofluorescence techniques; tick-borne encephalitis (TBE) specific IgM by immunosorbent assays or by reduction of hemagglutination-inhibition (HI) titer by 2-mercaptoethanol treatment of serum. Reports have been given on the detection of IgM activity by ELISA also in other arboviral infections such as Japanese and LaCrosse encephalitis. The demonstration of an intrathecal production of virus-specific immunoglobulins may reveal the type of virus causing the infection in the central nervous system.

Role of the virology laboratory in diagnosis and management of patients with central nervous system disease.

“…The disadvantages of the method are the need for maintaining a large number of antisera, the low sensitivity of the reagents under the required dilutions, and, in some samples, the lack of a sufficient number of leukocytes in the CSF for measurement (145). In addition, frequent nonspecific fluorescence of CSF lymphocytes has been reported by subsequent workers (52).…”

“…The tissue should be divided, with part being sent to the histology laboratory for immunoperoxidase staining and the rest inoculated into cell culture as described above. CSF is not usually positive for virus (52). Although development of methods to detect specific viral glycoprotein in CSF is in progress (127), no such procedures are currently available.…”

“…Virus has also been isolated from the CSF in some cases (123). Serologic recognition of the presence of specific IgM may be useful for diagnosing primary chicken pox but is not useful with herpes zoster (52).…”

“…This test can be confirmed by IF procedures for specific IgM to EBV capsid antigen. In children, the Monospot procedure is frequently negative, and the IF procedure is necessary to recognize infection with EBV (52). Although it is possible to isolate virus from blood or CSF, the procedure is slow and requires cultivation of the virus in lymphocytes.…”

“…No rapid procedures are available for diagnosing mumps (52). Isolation of the virus from CSF can be done in PMK, human diploid fibroblast, or HeLa cells.…”