Khan Salah Uddin, Salje Henrik, Hannan A, Islam Md Atiqul, Bhuyan A A Mamun, Islam Md Ariful, Rahman M Ziaur, Nahar Nazmun, Hossain M Jahangir, Luby Stephen P, Gurley Emily S
Centre for Communicable Diseases, i,cddr,b, Dhaka, Bangladesh; College of Public Health and Health Professions - Department of Environmental and Global Health, University of Florida, Gainesville, Florida, United States of America.
Department of Epidemiology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America.
PLoS Negl Trop Dis. 2014 Sep 25;8(9):e3166. doi: 10.1371/journal.pntd.0003166. eCollection 2014 Sep.
Japanese encephalitis (JE) virus infection can cause severe disease in humans, resulting in death or permanent neurologic deficits among survivors. Studies indicate that the incidence of JE is high in northwestern Bangladesh. Pigs are amplifying hosts for JE virus (JEV) and a potentially important source of virus in the environment. The objectives of this study were to describe the transmission dynamics of JEV among pigs in northwestern Bangladesh and estimate the potential impact of vaccination to reduce incidence among pigs.
METHODOLOGY/PRINCIPAL FINDINGS: We conducted a comprehensive census of pigs in three JE endemic districts and tested a sample of them for evidence of previous JEV infection. We built a compartmental model to describe JEV transmission dynamics in this region and to estimate the potential impact of pig vaccination. We identified 11,364 pigs in the study area. Previous JEV infection was identified in 30% of pigs with no spatial differences in the proportion of pigs that were seropositive across the study area. We estimated that JEV infects 20% of susceptible pigs each year and the basic reproductive number among pigs was 1.2. The model suggest that vaccinating 50% of pigs each year resulted in an estimated 82% reduction in annual incidence in pigs.
CONCLUSIONS/SIGNIFICANCE: The widespread distribution of historic JEV infection in pigs suggests they may play an important role in virus transmission in this area. Future studies are required to understand the contribution of pig infections to JE risk in humans and the potential impact of pig vaccination on human disease.
日本脑炎（JE）病毒感染可导致人类严重疾病，致使幸存者死亡或留下永久性神经功能缺损。研究表明，孟加拉国西北部的日本脑炎发病率很高。猪是日本脑炎病毒（JEV）的扩增宿主，也是环境中潜在的重要病毒来源。本研究的目的是描述孟加拉国西北部猪群中JEV的传播动态，并评估疫苗接种对降低猪群发病率的潜在影响。
方法/主要发现：我们对三个日本脑炎流行区的猪进行了全面普查，并对其中一部分猪进行检测，以寻找先前感染JEV的证据。我们构建了一个分区模型来描述该地区JEV的传播动态，并评估猪疫苗接种的潜在影响。我们在研究区域内识别出11364头猪。在30%的猪中发现了先前的JEV感染，且在整个研究区域内，血清呈阳性的猪的比例在空间上没有差异。我们估计，JEV每年感染20%的易感猪，猪群中的基本繁殖数为1.2。该模型表明，每年给50%的猪接种疫苗可使猪的年发病率估计降低82%。
结论/意义：猪群中既往JEV感染的广泛分布表明，它们可能在该地区的病毒传播中发挥重要作用。未来需要开展研究，以了解猪感染对人类感染JE风险的影响，以及猪疫苗接种对人类疾病的潜在影响。
