Epidemiological Profile of Acute Viral Encephalitis

Objective To study the etiology and clinico-epidemiological profile of acute viral encephalitis in children with acute encephalitis syndrome (AES). Methods An observational study including 100 patients fulfilling the criteria for AES was conducted in children of age group 1 mo - 16 y. Viral isolation was done on RD cells, HEp-2 cells and Vero cells from the cerebrospinal fluid samples of suspected viral encephalitis (VE) cases. An enzyme immunoassay for IgM antibodies was performed for measles, mumps, Varicella zoster virus (VZV), Herpes simplex virus 1 (HSV1) and Japanese encephalitis virus (JEV). Multiplex polymerase chain reaction (PCR) was done for Cytomegalovirus, Epstein Barr virus (EBV), HSV1 & 2, VZV, Enterovirus, Parecho virus, Human Herpes virus (HHV 6, 7) and Parvovirus B19. A micro neutralization test was performed for Enterovirus 71. Results Out of enrolled 100 patients, 73 were of probable viral encephalitis. HSV1 (31.50%) was the commonest virus followed by Adenovirus (10.95%), Parvovirus (2.73%), JE virus (1.36%), Enterovirus (1.36%), EBV (1.36%), and mixed infection with HSV & EBV (1.36%). HSV 1 caused significant morbidity in children. The common computed tomography (CT) findings were hypodensities in the fronto-parietal lobe followed by cerebral edema. Conclusions The landscape of AES in India has changed in the previous decade, and both outbreak investigations and surveillance studies have increasingly reported non-JEV etiologies; because of these findings there is a need to explore additional strategies to prevent AES beyond vector control and JEV vaccination.