ACUTE ENCEPHALITIS SYNDROME IN A TERTIARY CARE SETTING WITH SPECIAL REFERENCE TO JAPANESE ENCEPHALITIS: AN OBSERVATIONAL STUDY IN ASSAM, INDIA

Acute Encephalitis Syndrome (AES) is a major public health problem and Japanese Encephalitis (JE) is one of the most important causes of AES. Therefore, it is crucial to know the etiology of AES for patient management and decision making. The present study aimed to assess the morbidity and mortality profile of AES/JE patients admitted in tertiary care setting. An observational prospective cross-sectional study was conducted among 140 hospitalized AES patients admitted in Pediatric and Medicine ward of Jorhat Medical College and Hospital (JMCH), Jorhat over a period from August, 2017 to July 2018. Blood serum and cerebrospinal fiuids (CSF) were tested for presence of JE specific IgM antibody by Mac ELISA during acute illness of AES. The data were compiled and analyzed using the IBM SPSS, V23.0. Of the total 140 AES cases, majority (60%) were below 15 years age (p-value 0.180). Significantly higher proportion of AES cases were from rural areas (94.3%) (p-value <0.0001). The male and female ratio was 1.3:1. The most common presenting symptoms in AES patients were fever (100%), change in mental status (100%), seizure (56.4%) and headache (42.9%). Signs of meningeal irritation were present in 69.3% of cases. Around 22.9% AES patients had GCS ? 8. A total 49 (35%) cases were found to be laboratory confirmed JE following detection of JE specific IgM antibody. Among the JE patients, only 4.1% were immunized with SA 14-14-2 vaccine and 14% died before discharge. The complete recoveries were observed in 78% of cases. JE is one of the major causes of AES which is highly prevalent in this part of India. The significant findings in the present study calls for policy decision to combat JE.

Vaccination Policy for Japanese Encephalitis in India: Tread with Caution!.

Live attenuated SA-14-14-2 vaccine against Japanese encephalitis (JE) was introduced in the routine immunization under Universal Immunization Program in the 181 endemic districts of India. Recently, the Government of India has announced the introduction of one dose of JE vaccine for adults in endemic districts. The policy to mass vaccinate adults has raised several concerns that are discussed in this write-up. Apart from adult vaccination, the continuation of large scale JE vaccination program despite it being a very focal problem, and continued neglect of some other serious public health illnesses have also been highlighted. The issue of lack of authentic data on effectiveness of currently employed SA-14-14-2 JE vaccine has also been discussed.

Construction of A Stable Full-Length cDNA Clone of Japanese Encephalitis Virus Strain SA14-14-2 Using Low Copy Number Plasmid

Recently the reverse genetics system contributed to the progresses in the investigation of positive-stranded RNA viruses. Here, we report the successful construction of a stable full-length infectious cDNA clone of the live attenuated JEV vaccine strain SA14-14-2. The eleven kilobase viral RNA genome was reverse transcribed, amplified as four overlapping DNA fragments and successively ligated into the low copy number plasmid pACYC184, which contains the p15A origin of replication. In vitro-transcribed RNAs had a specific infectivity of approximately 104 PFU/microgram RNA, and the resulting virus exhibited growth kinetics and plaque morphology similar to the parental virus in cell culture. The structural and functional integrity of the cDNA clone was stably maintained even after at least 150 generations in Escherichia coli strain TOP10. The cDNA clone was engineered to contain single nucleotide change to create a XhoI site and knock out a XbaI site (A to C at nt 9134) acting as a genetic marker. This genetic marker was retained in the recovered progeny virus. Our results suggest that the instability of the full-length infectious JEV cDNA clone can be overcome by employing low copy number plasmid pACYC184. This infectious JEV cDNA clone will aid future studies of pathogenesis, virulence, and replication. Furthermore, it will facilitate the development of SA14-14-2 based recombinant vaccines.

Construction of A Stable Full-Length cDNA Clone of Japanese Encephalitis Virus Strain SA14-14-2 Using Low Copy Number Plasmid

Recently the reverse genetics system contributed to the progresses in the investigation of positive-stranded RNA viruses. Here, we report the successful construction of a stable full-length infectious cDNA clone of the live attenuated JEV vaccine strain SA14-14-2. The eleven kilobase viral RNA genome was reverse transcribed, amplified as four overlapping DNA fragments and successively ligated into the low copy number plasmid pACYC184, which contains the p15A origin of replication. In vitro-transcribed RNAs had a specific infectivity of approximately 104 PFU/microgram RNA, and the resulting virus exhibited growth kinetics and plaque morphology similar to the parental virus in cell culture. The structural and functional integrity of the cDNA clone was stably maintained even after at least 150 generations in Escherichia coli strain TOP10. The cDNA clone was engineered to contain single nucleotide change to create a XhoI site and knock out a XbaI site (A to C at nt 9134) acting as a genetic marker. This genetic marker was retained in the recovered progeny virus. Our results suggest that the instability of the full-length infectious JEV cDNA clone can be overcome by employing low copy number plasmid pACYC184. This infectious JEV cDNA clone will aid future studies of pathogenesis, virulence, and replication. Furthermore, it will facilitate the development of SA14-14-2 based recombinant vaccines.

Immune Response to SA14-14-2 Live Attenuated Japanese Encephalitis Vaccine

PURPOSE: SA14-14-2 live attenuated Japanese encephalitis (JE) vaccine has been administered safely and effectively to more than 100 million children in China since 1988, and recently licensure of the vaccine in Korea has been sought. Immune response to the vaccine was investigated. MEHTODS: In the first clinical evaluation of the vaccine outside of China, we monitored side effects in 93 children and evaluated plaque reduction neutralizing test (PRNT) antibody and IgM antibody responses to a single dose given as primary JE vaccination in 74 children, 1-3 years old (mean age 27 months). RESULTS: No significant adverse events were noted. PRNT antibodies (geometric mean titer [GMT] of 183) were produced in 96% of the 74 subjects. In 10 other children who previously had been immunized with two or three doses of inactivated JE vaccine, the booster administration of SA14-14-2 vaccine produced an anamnestic response in all, with a GMT of 3378. In a comparison group of 25 children previously immunized with two doses of inactivated vaccine, neutralizing antibody titers were detected in 16 (64%). Viral specific IgM was detected in nine primary vaccinees (13%) but in others, IgM may have declined to undetectable levels in the four week postimmunization sample. CONCLUSION: Live attenuated SA14-14-2 JE vaccine is a promising alternative to the only commercially available live attenuated JE vaccine for national childhood immunization programs in Asia.