An appraisal of seasonal pattern of AES in Chennai - Special Emphasis on JEV infections.

PURPOSE: This comprehensive epidemiological analysis with special emphasis on JEV infections was done to determine the seasonality and epidemiological trends of the AES and JEV occurrence in Chennai and adjoining districts.

METHODS

In our retrospective study, analysis of epidemiological data along with seasonality for AES cases and JEV for the period from 2021 to 2024 was done.

RESULTS

A total of 4581 AES suspected cases during the four-year period, referred from tertiary care centres in Chennai, were tested for JEV, with 340 (7.4%) JEV positives. On an average, there was a predominance of males when compared to females. The occurrence of AES and JEV peaked during the monsoon period of Aug, Nov & Dec during the monsoon months. When compared to adults, infants and young children in the under 15-year age group had shown a high positivity rate of JEV.

CONCLUSION

Epidemiological analysis showed increased prevalence of AES and JEV during the monsoon months. Since 2021, the incidence of Japanese Encephalitis virus had showed a marginal decrease in Tamil Nadu. The Government of India had implemented JEV vaccine SA-14-14-2 type among children in the age group of 1-15 years as a part of routine immunization (UIP) and on campaign mode in high-risk districts. Effective control measures anticipating outbreaks and clustering of cases are being taken up as a part of National program.