Monitoring Mosquito-Borne Arbovirus in Various Insect Regions in China in 2018

Abstract

BackgroundIncreases in global travel and trade are changing arbovirus distributions worldwide. Arboviruses can be introduced by travelers, migratory birds, or vectors transported via international trade. Arbovirus surveillance in field-collected mosquitoes may provide early evidence for mosquito-borne disease transmission.MethodsDuring the seasons of high mosquito activity of 2018, 29,285 mosquitoes were sampled from seven sentinel sites in various insect regions. The mosquitoes were analyzed by RT-PCR for alphaviruses, flaviviruses, and orthobunyaviruses.ResultsWe detected three strains of Japanese encephalitis virus (JEV), five strains of Getah virus (GETV), and 45 strains of insect-specific flaviviruses including Aedes flavivirus (AeFV, 1), Chaoyang virus (CHAOV, 1), Culex flavivirus (CxFV, 17), Hanko virus (HANKV, 2), QuangBinh virus (QBV, 22), and Yunnan Culex flavivirus (YNCxFV, 2). Whole genomes of one strain each of GETV, CxFV, CHAOV, and AeFV were successfully amplified. Phylogenetic analysis revealed that the new JEV strains detected in the Shanghai and Hubei Provinces belong to the GI-b strain and are phylogenetically close to the NX1889 strain (MT134112) isolated from a patient during a JE outbreak in Ningxia in 2018. GETVs were found in Inner Mongolia, Hubei, and Hainan and belonged to Group III. They were closely related to strains isolated from swine. HANKV was recorded for the first time in China and other ISFVs were newly detected at several sentinel sites. The bias-corrected maximum likelihood estimation value for JEV in Jinshan, Shanghai was 4.52/1,000 (range 0.80–14.64). Hence, there is a potential risk of a JEV epidemic in that region.ConclusionGI-b is the dominant circulating JEV genotype in nature and poses a health risk to animals and humans. The potential threat of widespread GETV distribution as a zoonosis is gradually increasing. The present study also disclosed the dispersion and host range of ISFVs. These findings highlight the importance of tracing the movements of the vectors and hosts of mosquito-borne pathogens in order to prevent and control arbovirus outbreaks in China.

Mosquito Vector Competence for Japanese Encephalitis Virus

“…In addition, JEV was detected over the last few decades in Cx . tritaeniorhynchus in Sri Lanka [ 52 ], India [ 39 , 53 , 62 , 63 , 64 , 65 , 66 , 68 , 69 , 99 , 100 , 101 , 121 , 122 , 126 ], Malaysia [ 29 ], Taiwan [ 116 ], Vietnam [ 106 ], South Korea [ 45 , 46 , 47 , 48 , 123 ], Taiwan [ 54 , 124 ], Japan [ 125 ] and China [ 85 , 127 , 128 ]. Simultaneously to the JEV isolation, Mitamura and colleagues also used Cx .…”

Diversity, Geography, and Host Range of Emerging Mosquito-Associated Viruses — China, 2010–2020

“…To date, records of TMUV have covered 18 provinces in China, and are mainly comprised of reports from the last decade ( 9 ). Similarly, the Getah virus, which is mainly transmitted between mosquitoes and domestic livestock, has been spreading across China since 2010 ( 10 ), with an outbreak on a swine farm in Hunan in 2017 ( 11 ). Moreover, despite having a relatively short history (first detected in 1997), the Liao ning virus (LNV) has been recorded in most of Northern China, including Beijing.…”

“…This group can be divided into monophyletic classical ISFVs (cISFVs) and dual-host ISFVs (dISFVs), with the latter being more closely related to mosquito-borne pathogenic flaviviruses (MBPFVs) speculated to have lost their ability to infect vertebrate cells during their evolution ( 14 ). There are three common cISFVs hosted by medically important mosquitoes: the Culex flavivirus (CxFV), the Quang Binh virus (QBV), and the Aedes flavivirus (AeFV) ( 10 , 15 ). The distribution and host range of the Hanko virus (Inner Mongolia, 2018), the Yunnan Culex flavivirus (Yunnan, 2009; 2018), the Culex theileri flavivirus (Yunnan, 2018), and the Yamadai flavivirus (Yunnan, 2018) in China are relatively localized ( 10 , 16 ).…”

“…There are three common cISFVs hosted by medically important mosquitoes: the Culex flavivirus (CxFV), the Quang Binh virus (QBV), and the Aedes flavivirus (AeFV) ( 10 , 15 ). The distribution and host range of the Hanko virus (Inner Mongolia, 2018), the Yunnan Culex flavivirus (Yunnan, 2009; 2018), the Culex theileri flavivirus (Yunnan, 2018), and the Yamadai flavivirus (Yunnan, 2018) in China are relatively localized ( 10 , 16 ). In some instances, a high prevalence of ISFVs have been observed in the field, such as QBV (21.53/1000) in Cx.…”

“…pipiens in Jining, CxFV (61.25/1000) in Cx. tritaeniorhynchus in Sanya, and AeFV (33.93/1000) in Aedes albopictus in Songjiang District, Shanghai ( 10 , 15 ). By contrast, the distribution and host range of dISFVs are narrower than that of cISFVs.…”