Comparison of Shell vial Culture assay and molecular methods including a molecular chip for diagnosis of acute viral encephalitis in Northern India

Introduction: Viral encephalitis is potentially fatal disease which requires rapid diagnosis and management and should be ruled out from other infectious and noninfectious cases. Serological tests can only presumptively diagnose the condition. Cell culture methods are definitive diagnostic test but require comparatively longer time. Shell vial culture is better than conventional cell culture methods being more sensitive and rapid. Molecular methods like Polymerase Chain Reaction (PCR) can rapidly diagnose but its sensitivity needs to be evaluated. Finally newer microarray techniques can detect multiple viruses in a syndromic approach. So, this study was carried out to evaluate conventional cell culture, shell vial culture and PCR to diagnose viral encephalitis. Materials and Methods: 203 consecutive clinically suspected patients with encephalitis, Dengue and Chikungunya fever were included. From each patient, blood and CSF samples were collected and inoculated on both conventional and shell vial culture. CSF samples were inoculated on RD (Rhabdomyosarcoma) for the Enterovirus isolation. PS ( Stable Porcine cells) were used for JE. Serum samples were inoculated on C6/36 for Dengue virus and chikungunya virus isolation. All cell culture positive samples were subjected to molecular detection by RT-PCR. All the cell culture negative samples tested by a molecular chip developed by NIMHANS Bengaluru and XCyton Diagnostics Pvt Ltd Bengaluru. Results: The positivity of conventional cell culture were 5 (2.4%), 6 (2.9%) 4(1.9%) samples respectively. In comparison, the positivity of shell vial cultures were 7 (3.4%), 10 (4.9%), 6 (2.9%) respectively. The corresponding positivity of RT-PCR were 3 (1.5 %) JE, 8 (3.9%) Enterovirueses , 4 (1.9%) Dengue and 0 chikungunya cases. All cell culture negative samples were negative by molecular chip methods except one sample which was positive for JC virus. Conclusion: We recommend shell vial culture in diagnosis of viral encephalitis cases due to its better positivity and rapidity over conventional cellculture. It shows better positivity than RT-PCR.