Samuel P Philip, Thenmozhi V, Muniaraj M, Ramesh D, Jerald Leo S Victor, Balaji T, Venkatasubramani K, Nagaraj J, Paramasivan R
ICMR-Centre for Research in Medical Entomology, Madurai, India.
J Vector Borne Dis. 2018 Jul-Sep;55(3):203-207. doi: 10.4103/0972-9062.249130.
BACKGROUND & OBJECTIVES: Japanese encephalitis (JE) is a mosquito-borne zoonotic disease. The JE virus (JEV) does not cause any disease among its natural hosts and transmission continues through mosquitoes belonging to Culex vishnui subgroup. This study was aimed to investigate the prevalence of JEV in mosquitoes and humans in the Thanjavur district, a non-endemic region for JE, in Tamil Nadu, by using standard available assays.
: A sero-surveillance study was conducted in Thanjavur district among the normal rural school children in the 5-12 yr age group, during the JE season (October) and post-JE season (February) from 2011 to 2013 for the detection of JEV infection. Vector abundance studies were carried out from 2011 to 2014. JE seropositivity and its association between the seasons were analysed statistically.
: The occurrence of JE infection among children aged 5-12 yr was very high in the study area. The infection rates for JE in two consecutive seasons for 2011-12 and 2012-13 were 32.2 and 65.2%, respectively. The Cx. tritaeniorhynchus sp. dominated the catch, and was majorly responsible for the transmission. There was a significant difference in the human infection rate compared to the years 1991-92 and 1992-93; and a marked decrease in the cattle to pigs ratio (123 : 1) compared to the studies in 1991-93.
INTERPRETATION & CONCLUSION: : The study unearthed the prevailing situation of JE among children, who are at higher risk of developing the disease during the transmission season. The decrease in the cattle to pigs ratio might be the one of the reasons for increase in the JEV infection among the children population compared to 20 years before. This trend requires urgent attention as it could be prevented with effective surveillance systems and vaccines.
日本脑炎（乙脑）是一种由蚊子传播的人畜共患病。乙脑病毒（JEV）在其天然宿主中不会引发任何疾病，且通过属于致倦库蚊亚组的蚊子持续传播。本研究旨在通过使用标准可用检测方法，调查泰米尔纳德邦坦贾武尔地区（乙脑非流行地区）蚊子和人类中JEV的流行情况。
2011年至2013年期间，在乙脑季节（10月）和乙脑季节后（2月），对坦贾武尔地区5至12岁的农村正常学童进行了血清监测研究，以检测JEV感染情况。2011年至2014年开展了媒介丰度研究。对乙脑血清阳性率及其季节间关联进行了统计分析。
研究区域内5至12岁儿童的乙脑感染发生率非常高。2011 - 12年和2012 - 13年连续两个季节的乙脑感染率分别为32.2%和65.2%。三带喙库蚊在捕获的蚊子中占主导地位，是主要的传播媒介。与1991 - 92年和1992 - 93年相比，人类感染率存在显著差异；与1991 - 93年的研究相比，牛与猪的比例显著下降（123∶1）。
该研究揭示了儿童中乙脑的流行状况，这些儿童在传播季节患该病的风险更高。与20年前相比，牛与猪比例的下降可能是儿童群体中JEV感染增加的原因之一。这一趋势需要紧急关注，因为通过有效的监测系统和疫苗可以预防这种情况。
