Division of Veterinary Public Health, ICAR - Indian Veterinary Research Institute, Bareilly, Uttar Pradesh, India.
Centre for One Health, Guru Angad Dev Veterinary & Animal Sciences University, Ludhiana, Punjab, India.
Trop Anim Health Prod. 2024 Nov 28;56(9):397. doi: 10.1007/s11250-024-04243-0.
Japanese encephalitis (JE) is widely prevalent in the Asia-Pacific region. There is limited information on JE virus (JEV) seroprevalence as well as the associated epidemiologic and ecological factors in India. This study aimed to determine the seroprevalence of JEV and associated risk factors in swine populations from climatically diverse regions of the country. A total of 1205 swine serum samples were collected from the backyard/established/slaughterhouse settings of the western (Maharashtra state), northern (Uttar Pradesh state), northern temperate (Uttarakhand state), and northeastern (Assam state) zones of India. Information on demographic (swine population), geographic (paddy cultivation area) and weather (annual rainfall)-related variables was collected and analysed to understand their association with JE seropositivity. A JEV seroprevalence of 20.3% (95% CI: 17.9-22.7) using IgM and 16.6% (95% CI: 14.3-19.1) using IgG ELISA(s) was recorded, with an overall seroprevalence of 17.7% (95% CI: 15.8-19.6). The highest seroprevalence was observed in Assam state (30.2%; 95% CI: 25.9-34.7) followed by Maharashtra (17.2%; 95% CI: 13.6-21.1), Uttarakhand (13.4%; 95% CI: 10.1-17.3) and Uttar Pradesh (11%; 95% CI: 8.2-14.3). JEV seroprevalence was highest during the post-monsoon season (40.3%, 95% CI: 34.7-46.0, n = 205), followed by the monsoon (18.9%, 95% CI: 15.7-22.2, n = 410), winter (17.0%, 95% CI: 13.5-20.9, n = 290), and summer (3.7%, 95% CI: 1.9-6.2, n = 300) seasons. The final multivariable analysis indicated that odds of infection were 2.59 (95% CI: 1.77-3.81, p = 0.001) times greater in the dense swine population area (population > 7616-81872 v/s 313-2006) and 5.77 (95% CI: 3.80-8.76, p = < 0.001) times greater in the small per capita paddy area (0-0.011 v/s > 0.046-0.091 hectares). This is the first study reporting JEV seroprevalence in the swine population of the northern temperate Indian zone, and it is recommended that sentinel surveillance and JE vaccine coverage be extended to the newly reported areas of virus activity.
日本脑炎（JE）在亚太地区广泛流行。关于印度 JE 病毒（JEV）血清流行率以及相关的流行病学和生态因素的信息有限。本研究旨在确定来自该国气候多样地区的猪群中 JEV 的血清流行率以及相关的风险因素。从印度西部（马哈拉施特拉邦）、北部（北方邦）、北部温带（北阿坎德邦）和东北部（阿萨姆邦）地区的后院/建立/屠宰场环境中采集了总共 1205 份猪血清样本。收集了有关人口统计学（猪群）、地理（稻田种植面积）和天气（年降雨量）相关变量的信息，并进行了分析，以了解它们与 JE 血清阳性的关系。使用 IgM 检测到 JEV 血清流行率为 20.3%（95%CI：17.9-22.7），使用 IgG ELISA 检测到 16.6%（95%CI：14.3-19.1），总体血清流行率为 17.7%（95%CI：15.8-19.6）。阿萨姆邦的血清流行率最高（30.2%；95%CI：25.9-34.7），其次是马哈拉施特拉邦（17.2%；95%CI：13.6-21.1）、北阿坎德邦（13.4%；95%CI：10.1-17.3）和北方邦（11%；95%CI：8.2-14.3）。JEV 血清流行率在后季风季节最高（40.3%；95%CI：34.7-46.0，n=205），其次是季风季节（18.9%；95%CI：15.7-22.2，n=410），冬季（17.0%；95%CI：13.5-20.9，n=290）和夏季（3.7%；95%CI：1.9-6.2，n=300）。最终的多变量分析表明，在密集的猪群地区（人口>7616-81872 与 313-2006），感染的可能性是人口较少的猪群地区（人口 313-2006）的 2.59 倍（95%CI：1.77-3.81，p=0.001），在小的人均稻田面积地区（0-0.011 与>0.046-0.091 公顷），感染的可能性是人均稻田面积较大的地区的 5.77 倍（95%CI：3.80-8.76，p<0.001）。这是第一项报告印度北部温带地区猪群 JEV 血清流行率的研究，建议扩大哨点监测和 JEV 疫苗接种范围，覆盖新报告的病毒活动地区。
