Trend of Japanese encephalitis in North India: evidence from thirty-eight acute encephalitis cases and appraisal of niceties

Abstract

Background: In the year 2005, an epidemic of Japanese encephalitis (JE) occurred in the northern states of India. The present study was planned to reconfirm the circulation of JE in the area and to assess the trend of the disease to slow down the burden of JE. Methodology: Surveillance was conducted to identify patients with acute encephalitis. Blood and cerebrospinal fluid specimens from suspected cases underwent pathological, serological, and demographic investigations. Viral testing for evidence of Japanese encephalitis virus (JEV) infection was also performed, either by IgM capture ELISA/RT-PCR or both. To identify circulating JEV strains, RT-PCR, sequencing and phylogenetic analysis was performed. Based on clinical cases reported between 1992 and 2008, the trend of JE infection in the state was analyzed to examine the dynamics of infection. Results: Our investigations (n = 38) revealed that only 55.3% cases were positive for JE. Pathological examination revealed marked pleocytosis in CSF (90 76.9 cells/mm 3 ), and peripheral leucocytosis (64.7 8.86% neutrophils) with mild anemia. Males were more susceptible than females with a ratio of 1.63:1 and significant gender difference (P 0.05) was observed in patients below six years. In the patient group younger than six years, the rate of infection per million was six-fold higher (P 0.005) in males as compared to females. Our phylogenetic study suggests that the circulating strain during the 2005 JE epidemic was close to GP78, and in the future a larger epidemic may occur. Conclusions: The 2005 JE epidemic was possibly caused by JEV GP78 and it is spreading into newer areas. The trend of JE suggests that the problem in North India is escalating and larger epidemics may occur in the future; therefore, serious steps are necessary to combat JE, including the development of more efficient surveillance methods and differential diagnosis.

Epidemiology and Etiology of Acute Encephalitis Syndrome in North India

“…Mental retardation and neurological deficits were observed among survivors of JEV infection, as has been previously reported (5). Mortality rate of 22z and 11.7z were found to be associated with dengue encephalopathy in a previous and the current studies, respectively, while complete recovery without any residual illness was observed in both the studies (33).…”

“…A limited number of etiologic agents were tested, which did not include non-viral causative agents of AES. The patients were not monitored after discharge from the hospital; hence, long-term sequelae, which are known among survivors of viral infection, have not been examined (5,35,36).…”

“…The growth of vector mosquito population is favored by the accumulation of water and extensive rice cultivation in the Terai region of eastern UP and other adjoining regions that run parallel to the lower ranges of the Himalayas. Besides JEV, other viruses that have contributed to the high incidence of AES in India include the dengue virus (DV), enterovirus, herpes simplex virus (HSV), measles virus, and Chandipura virus (5); however, the etiology of AES remains unknown in 68z-75z of the patients (6). An accurate identification of the organism causing AES is essential for surveillance and patient management because some of these infections are preventable or treatable.…”

Prevention, diagnosis, and management of Japanese encephalitis in children

“…35,37 Until 2007, all known Indian JEV strains belonged to genotype III. 35,[38][39][40] However, JEV genotype I has been introduced into the People's Republic of China, South Korea, and Thailand over the past decade 41 and recently, genotype I has been isolated from the Gorakhpur region, India.…”

Japanese Encephalitis: An Emerging and Spreading Arbovirosis

“…Sequence analyses of viral genes are further showing that a "genotype shift" from III to I has occurred in Japan since early 1990s, reasons for which remains unclear (Shimojima et al, 2011). Japanese encephalitis (JE) is spreading in the newer areas of northern states of India (Saxena et al, 2006(Saxena et al, , 2009.…”