Recent Trends and Changing Aetiology of Acute Encephalitis Syndrome in India

Acute Encephalitis Syndrome (AES) poses a great public health problem in India, occurring both in epidemics and sporadically. Although bacteria, viruses and protozoan parasites may cause encephalitis, among these; the viruses are the most common and important cause of encephalitis Japanese Encephalitis virus has been considered as leading cause of AES in India mostly occurs among children. Thus, the disease spectrum of AES seems to be much wider and may be caused by a wide variety of viruses, bacteria, protozoa, fungi, or may even be non-infectious in aetiology. Recently, increased incidence of scrub typhus is being reported from Northern India especially eastern part of Uttar Pradesh and western part of Bihar, as reported 25% infectious aetiology in one third of the AES cases and emergence of O. tsutsugamushi infection an important causative agent of AES in India. A recent outbreak of "AES" in June 2019 was found in Muzaffarpur, Bihar India. As reported the Muzaffarpur district has initiated an investigation into the case of 672 children who were admitted with "AES" and more than 150 children have died. Case fatality rate among children due to JE was found very low now because changing aetiology of AES across various districts of Bihar.