Genetic Characterization of Japanese Encephalitis Virus Isolates Circulating in Mosquitoes from Pig and Sheep Farms in Shanghai, China
by
, , , , ,
Hailong Zhang
1,
Dan Li
2,
Jiayang Zheng
2,
Yan Zhang
2,
Zongjie Li
2,
Ke Liu
2,
Beibei Li
2,
Yafeng Qiu
2
,
Donghua Shao
2,
Soesoe Wai
3,
Jianchao Wei
2,
Zhiyong Ma
2,* and
Juxiang Liu
1,* 1
College of Veterinary Medicine, Hebei Agricultural University, Baoding 071000, China
2
Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
3
Department of Veterinary Public Health, University of Veterinary Science, Yezin 15013, Myanmar
*
Authors to whom correspondence should be addressed.
Animals 2024, 14(24), 3653; https://doi.org/10.3390/ani14243653
Submission received: 14 November 2024
/
Revised: 15 December 2024
/
Accepted: 16 December 2024
/
Published: 18 December 2024
(This article belongs to the Special Issue Pathogenesis, Immunology and Epidemiology of Veterinary Viruses)
Simple Summary
Japanese encephalitis virus (JEV) is a major cause of viral encephalitis in hu-mans, but research on its genotype prevalence in mosquitoes in Shanghai is limited. This study surveyed mosquito diversity and JEV prevalence in pig and sheep farms in Shanghai in 2022. A total of 24,073 mosquitoes from four genera and seven species were collected across five districts. Culex tritaeniorhynchus was the most common species (87.09%, 20,965/24,073) with the highest JEV detection rate. Six JEV strains were isolated, with five (SH22-M5, SH22-M9, SH22-M14, SH22-M41, and SH22-M52) classified as genotype I (GI) and one (SH22-M1) as genotype III (GIII). SH22-M9 and SH22-M14 showed high homology with SD-1 (99.87%) and SD12 (99.53%), respectively. SH22-M5, SH22-M41, and SH22-M52 shared 99.73–99.93% homology with the HEN07011 strain. SH22-M1 was most similar to SH18 (99.8%). This study also reports the first isolation of a GI JEV strain from mosquitoes in sheep farms. The findings underscore the need for enhanced JEV surveillance in livestock and mosquito monitoring to reduce the risk of human infections, recommending the separation of livestock and human habitation.
Abstract
Japanese encephalitis virus (JEV) is regarded as an emerging and reemerging pathogen that is a primary cause of viral encephalitis in humans. However, there is a scarcity of research on the prevalence of JEV genotypes across the different mosquito species in Shanghai. In this study, the diversity of mosquito species and prevalence of JEV in pig and sheep farms in Shanghai were surveyed in 2022. A total of 24,073 mosquitoes, belonging to four genera and seven species, were collected from pig and sheep enclosures in the Chongming, Jiading, Pudong, Fengxian, and Jinshan Districts of Shanghai. Culex tritaeniorhynchus was identified as the predominant species (87.09%, 20,965/24,073) with the highest JEV detection rate. Six strains of JEV were isolated in this study, and genetic analysis revealed that five strains (SH22-M5, SH22-M9, SH22-M14, SH22-M41, and SH22-M52) belonged to genotype I (GI), while one strain (SH22-M1) was classified as genotype III (GIII). The sequence homology was highest between SH22-M9 and SD-1 (99.87%) and between SH22-M14 and SD12 (99.53%). SH22-M5, SH22-M41, and SH22-M52 shared the highest sequence homology with the HEN07011 strain (99.73–99.93%). SH22-M1 was most closely related to SH18, with a sequence homology of 99.8%. Additionally, for the first time, the GI JEV strain was isolated from mosquitoes in sheep sties in this study. The findings highlight the necessity of enhancing the surveillance of JEV in pigs and other livestock farms, including sheep, as well as monitoring the mosquitoes present in these environments. It is recommended that livestock farming areas be kept separate from human habitation to reduce the risk of JEV infections in humans.
