Zhang Hui, Luo Houqiang, Ur Rehman Mujeeb, Nabi Fazul, Li Kun, Lan Yanfang, Huang Shucheng, Zhang Lihong, Mehmood Khalid, Shahzad Muhammad, Li Jiakui
College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.
College of Veterinary Medicine, Huazhong Agricultural University, Wuhan; China; College of Veterinary and AnimalSciences, Islamia University of Bahawalpur, Pakistan.
J Vector Borne Dis. 2017 Jan-Mar;54(1):69-73.
BACKGROUND & OBJECTIVES: Culex tritaeniorhynchus is the primary vector of Japanese encephalitis virus (JEV) which is a major threat to animals and humans health. This virus has been reported earlier from low altitude regions of Tibet, in mosquitoes, Tibetan pigs and local Tibetans, but no reports are available for the probable propagation of JE to high altitude regions (3100 m) of Tibet. This study aimed to find the evidence of JEV in Cx. tritaeniorhynchus and pigs from high altitude regions of Tibet, China.
In total, 102 porcine serum samples and eight pools of Cx. tritaeniorhynchus were subjected to real-time PCR (RT-PCR) for the amplification of a fragment (~ 420 bp) of the NS1 gene. The resultant amplicons of the genes were subsequently analyzed and sequenced.
Overall seroprevalence of JE in Tibetan pigs was 6.86%, while five pools of Cx. tritaeniorhynchus were found positive for JEV. Results showed genotype III as the most prevalent (100%) among JEV positive isolates. Furthermore, phylogenetic analysis of the JEV positive strains showed 98.8-99% similarity to four reference strains from China (JEV-Hubei, Whe, HYZ and CQ11-66).
INTERPRETATION & CONCLUSION: The present study revealed that JEV has extended its geographic range to high altitude regions of Tibet. The factors like increased tourism and transportation might play key role in the transmission of JE that comprises a potential health risk for humans and animals.
三带喙库蚊是日本脑炎病毒（JEV）的主要传播媒介，对动物和人类健康构成重大威胁。此前已在西藏低海拔地区的蚊子、藏猪和当地藏族人群中发现该病毒，但尚无关于日本脑炎在西藏高海拔地区（3100米）可能传播的报道。本研究旨在寻找中国西藏高海拔地区三带喙库蚊和猪体内JEV的证据。
总共对102份猪血清样本和8组三带喙库蚊进行实时聚合酶链反应（RT-PCR），以扩增NS1基因的一个片段（约420bp）。随后对所得基因扩增产物进行分析和测序。
藏猪中日本脑炎的总体血清阳性率为6.86%，同时发现5组三带喙库蚊JEV呈阳性。结果显示，III型基因型在JEV阳性分离株中最为常见（100%）。此外，对JEV阳性菌株的系统发育分析表明，其与来自中国的4个参考菌株（JEV-湖北、Whe、HYZ和CQ11-66）的相似性为98.8-99%。
本研究表明，JEV的地理分布范围已扩展至西藏高海拔地区。旅游业和交通运输增加等因素可能在日本脑炎的传播中起关键作用，对人类和动物构成潜在健康风险。
