scholarly journals Mosquito Vector Competence for Japanese Encephalitis Virus

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1154
Author(s):  
Heidi Auerswald ◽  
Pierre-Olivier Maquart ◽  
Véronique Chevalier ◽  
Sebastien Boyer
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Vector Competence ◽  
Mosquito Species ◽  
Encephalitis Virus ◽  
Control Measures ◽  
Local Context ◽  
Mosquito Vector ◽  
Vector Species ◽  
Local Climate

Japanese encephalitis virus (JEV) is a zoonotic pathogen mainly found in East and Southeast Asia and transmitted by mosquitoes. The objective of this review is to summarize the knowledge on the diversity of JEV mosquito vector species. Therefore, we systematically analyzed reports of JEV found in field-caught mosquitoes as well as experimental vector competence studies. Based on the investigated publications, we classified 14 species as confirmed vectors for JEV due to their documented experimental vector competence and evidence of JEV found in wild mosquitoes. Additionally, we identified 11 mosquito species, belonging to five genera, with an experimentally confirmed vector competence for JEV but lacking evidence on their JEV transmission capacity from field-caught mosquitoes. Our study highlights the diversity of confirmed and potential JEV vector species. We also emphasize the variety in the study design of vector competence investigations. To account for the diversity of the vector species and regional circumstances, JEV vector competence should be studied in the local context, using local mosquitoes with local virus strains under local climate conditions to achieve reliable data. In addition, harmonization of the design of vector competence experiments would lead to better comparable data, informing vector and disease control measures.

scholarly journals A dataset of distribution and diversity of mosquito-associated viruses and their mosquito vectors in China

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Evans Atoni ◽  
Lu Zhao ◽  
Cheng Hu ◽  
Nanjie Ren ◽  
Xiaoyu Wang ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Mosquito Species ◽  
Encephalitis Virus ◽  
Health Concern ◽  
Mosquito Vector ◽  
Mosquito Vectors ◽  
Culex Flavivirus ◽  
Conference Papers

Abstract Mosquito-borne viruses such as Zika virus, Japanese Encephalitis virus and Dengue virus present an increasing global health concern. However, in-depth knowledge of the distribution and diversity of mosquito-associated viruses and their related vectors remains limited, especially for China. To promote their understanding, we present the first comprehensive dataset of the distribution and diversity of these viruses and their related vectors in China (including Taiwan, Hong Kong and Macau). Data was drawn from peer-reviewed journal articles, conference papers and thesis publications in both English and Chinese. Geographical data on mosquito-associated viruses’ occurrence and related mosquito vector species was extracted, and quality-control processes employed. This dataset contains 2,428 accounts of mosquito-associated viruses’ and mosquito species geo-referenced occurrences at various administrative levels in China. The prevalent mosquito-associated virus includes Japanese encephalitis virus, Dengue virus, Banna virus and Culex flavivirus, whereas the abundant mosquito vectors are Culex tritaeryohynchus, Aedes albopictus and Culex pipiens pallens. This geographical dataset delivers a distribution and diversity outline of mosquito-associated viruses in China, and also applicable in various spatial and risk-assessment analysis.

scholarly journals Experimental Evaluation of the Role of Ecologically-Relevant Hosts and Vectors in Japanese Encephalitis Virus Genotype Displacement

Viruses ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 32 ◽  
Author(s):  
Ajit K. Karna ◽  
Richard A. Bowen
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Experimental Evaluation ◽  
Encephalitis Virus ◽  
Viral Fitness ◽  
Avian Host ◽  
Mosquito Vector ◽  
Virus Genotype ◽  
Southern Asia

Japanese encephalitis virus (JEV) is a flavivirus that is maintained via transmission between Culex spp. mosquitoes and water birds across a large swath of southern Asia and northern Australia. Currently JEV is the leading cause of vaccine-preventable encephalitis in humans in Asia. Five genotypes of JEV (G-I–G-V) have been responsible for historical and current outbreaks in endemic regions, and G-I and G-III co-circulate throughout Southern Asia. While G-III has historically been the dominant genotype worldwide, G-I has gradually but steadily displaced G-III. The objective of this study was to better understand the phenomenon of genotype displacement for JEV by evaluating both avian host and mosquito vector susceptibilities to infection with representatives from both G-I and G-III. Since ducks and Culex quinquefasciatus mosquitoes are prevalent avian hosts and vectors perpetuating JEV transmission in JE endemic areas, experimental evaluation of virus replication in these species was considered to approximate the natural conditions necessary for studying the role of host, vectors and viral fitness in the JEV genotype displacement context. We evaluated viremia in ducklings infected with G-I and G-III, and did not detect differences in magnitude or duration of viremia. Testing the same viruses in mosquitoes revealed that the rates of infection, dissemination and transmission were higher in virus strains belonging to G-I than G-III, and that the extrinsic incubation period was shorter for the G-I strains. These data suggest that the characteristics of JEV infection of mosquitoes but not of ducklings, may have play a role in genotype displacement.

scholarly journals Vector Competence of Australian Mosquitoes (Diptera: Culicidae) for Japanese Encephalitis Virus

2003 ◽  
Vol 40 (1) ◽  
pp. 82-90 ◽  
Author(s):  
A. F. Van Den Hurk ◽  
D. J. Nisbet ◽  
R. A. Hall ◽  
B. H. Kay ◽  
J. S. Mackenzie ◽  
...  
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Vector Competence ◽  
Encephalitis Virus

scholarly journals The feasibility of field collected pig oronasal secretions as specimens for the virologic surveillance of Japanese encephalitis virus

2021 ◽  
Vol 15 (12) ◽  
pp. e0009977
Author(s):  
Shyan-Song Chiou ◽  
Jo-Mei Chen ◽  
Yi-Ying Chen ◽  
Min-Yuan Chia ◽  
Yi-Chin Fan
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Encephalitis Virus ◽  
Mosquito Vector ◽  
Rt Pcr ◽  
Viral Rnas ◽  
Epidemic Area ◽  
Route Of Transmission ◽  
Pig Farm ◽  
Blood Specimens

Virologic surveillance of Japanese encephalitis virus (JEV) relies on collecting pig blood specimens and adult mosquitoes in the past. Viral RNAs extracted from pig blood specimens suffer from low detecting positivity by reverse transcription PCR (RT-PCR). The oronasal transmission of the virus has been demonstrated in experimentally infected pigs. This observation suggested oronasal specimens could be useful source in the virus surveillance. However, the role of this unusual route of transmission remains unproven in the operational pig farm. In this study, we explore the feasibility of using pig oronasal secretions collected by chewing ropes to improve the positivity of detection in commercial pig farms. The multiplex genotype-specific RT-PCR was used in this study to determine and compare the positivity of detecting JEV viral RNAs in pig’s oronasal secretions and blood specimens, and the primary mosquito vector. Oronasal specimens had the overall positive rate of 6.0% (95% CI 1.3%–16.6%) (3/50) to 10.0% (95% CI 2.1%–26.5%) (3/30) for JEV during transmission period despite the negative results of all blood-derived specimens (n = 2442). Interestingly, pig oronasal secretions and female Culex tritaeniorhynchus mosquito samples collected from the same pig farm showed similar viral RNA positive rates, 10.0% (95% CI 2.1%–26.5%) (3/30) and 8.9% (95% CI 2.5%–21.2%) (4/45), respectively (p> 0.05). Pig oronasal secretion-based surveillance revealed the seasonality of viral activity and identified closely related genotype I virus derived from the mosquito isolates. This finding indicates oronasal secretion-based RT-PCR assay can be a non-invasive, alternative method of implementing JEV surveillance in the epidemic area prior to the circulation of virus-positive mosquitoes.

scholarly journals What are the implications of genetic variation for the control of Japanese encephalitis virus?

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
John Bish ◽  
Nicola Rose ◽  
Janet Daly
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Current Control ◽  
Encephalitis Virus ◽  
Control Measures ◽  
Vaccine Protection ◽  
Live Attenuated Vaccine ◽  
Virus Like Particle ◽  
Dominant Genotype

Japanese encephalitis virus (JEV) is the leading cause of viral encephalitis worldwide. Annually it causes between 13,000 and 20,000 deaths mainly in South-East Asia. Vaccination programmes have drastically reduced the number of JEV cases however outbreaks do still occur. Recently G1 has overtaken G3 as the dominant genotype in most endemic countries and as all currently licensed vaccines are based on G3 it is necessary to evaluate the potential of emerging genotypes to break through current control measures. This project seeks to generate a virus-like-particle (VLP) neutralisation assay in order to investigate the potential for emergent or divergent genotypes of JEV to infect vaccinated individuals. Using this assay, we will evaluate the ability of vaccinee sera to neutralise emergent genotypes as well as to introduce a variety of SNPs that have been shown to enhance virulence and investigate whether any combination of these are able to invalidate vaccine protection. There is also concern that recombination between wild-type and live attenuated vaccine strains may occur in the vaccine setting which could result in rescue of the virulent potential of the attenuated virus. Evidence of this is being sought in silico using publicly available data and existing techniques. These data will provide a clearer picture of the nature of JEV in endemic areas and whether the current strategy of vaccination is sufficient to prevent naturally acquired infection in the long term or if other strategies must now be considered.

scholarly journals Host-Feeding Preference and Diel Activity of Mosquito Vectors of the Japanese Encephalitis Virus in Rural Cambodia

Pathogens ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 376
Author(s):  
Sébastien Boyer ◽  
Benoit Durand ◽  
Sony Yean ◽  
Cécile Brengues ◽  
Pierre-Olivier Maquart ◽  
...  
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Control Strategies ◽  
Mosquito Species ◽  
Feeding Preference ◽  
Encephalitis Virus ◽  
Diel Activity ◽  
Host Feeding ◽  
Large Numbers ◽  
Dog Blood

Japanese Encephalitis (JE) is the most important cause of human encephalitis in Southeast Asia, and this zoonosis is mainly transmitted from pigs to human by mosquitoes. A better understanding of the host-feeding preference of Japanese encephalitis virus (JEV) major vectors is crucial for identifying risk areas, defining bridge vector species and targeting adapted vector control strategies. To assess host-feeding preference of JE vectors in a rural Cambodian area where JE is known to circulate, in 2017, we implemented four sessions of mosquito trapping (March, June, September, December), during five consecutive nights, collecting four times a night (6 p.m. to 6 a.m.), and using five baited traps simultaneously, i.e., cow, chicken, pig, human, and a blank one for control. In addition, blood meals of 157 engorged females trapped at the same location were opportunistically analyzed with polymerase chain reaction (PCR), using cow, pig, human, and dog blood primers. More than 95% of the 36,709 trapped mosquitoes were potential JE vectors. These vectors were trapped in large numbers throughout the year, including during the dry season, and from 6 p.m. to 6 a.m. Despite the apparent host-feeding preference of Culex vishnui, Cx. gelidus, and Cx. tritaenhyorhincus for cows, statistical analysis suggested that the primary target of these three mosquito species were pigs. Dog blood was detected in eight mosquitoes of the 157 tested, showing that mosquitoes also bite dogs, and suggesting that dogs may be used as proxy of the risk for human to get infected by JE virus.

scholarly journals Evaluating the competence of the primary vector, Culex tritaeniorhynchus, and the invasive mosquito species, Aedes japonicus japonicus, in transmitting three Japanese encephalitis virus genotypes

2020 ◽  
Vol 14 (12) ◽  
pp. e0008986
Author(s):  
Astri Nur Faizah ◽  
Daisuke Kobayashi ◽  
Michael Amoa-Bosompem ◽  
Yukiko Higa ◽  
Yoshio Tsuda ◽  
...  
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Transmission Rate ◽  
Mosquito Species ◽  
Encephalitis Virus ◽  
Disease Spread ◽  
Aedes Japonicus ◽  
Culex Tritaeniorhynchus ◽  
Aedes Japonicus Japonicus ◽  
Primary Vector

Japanese encephalitis virus (JEV) is maintained in an enzootic cycle between swine, water birds, and mosquitoes. JEV has circulated indigenously in Asia, with Culex tritaeniorhynchus as the primary vector. In some areas where the primary vector is scarce or absent, sporadic cases of Japanese encephalitis have been reported, with Aedes japonicus japonicus presumed to have the potential as a secondary vector. As one of the world’s most invasive culicid species, Ae. j. japonicus carries a considerable health risk for spreading diseases to wider areas, including Europe and North America. Thus, evaluation of its competency as a JEV vector, particularly in a native population, will be essential in preventing potential disease spread. In this study, the two mosquito species’ vector competence in transmitting three JEV genotypes (I, III, and V) was assessed, with Cx. tritaeniorhynchus serving as a point of reference. The mosquitoes were virus-fed and the infection rate (IR), dissemination rate (DR), and transmission rate (TR) evaluated individually by either RT-qPCR or focus forming assay. Results showed striking differences between the two species, with IR of 95% (261/274) and 9% (16/177) in Cx. tritaeniorhynchus and Ae. j. japonicus, respectively. Both mosquitoes were susceptible to all three JEV genotypes with significant differences in IR and mean viral titer. Results confirm the primary vector’s competence, but the fact that JEV was able to establish in Ae. j. japonicus is of public health significance, and with 2%–16% transmission rate it has the potential to successfully transmit JEV to the next host. This may explain the human cases and infrequent detection in primary vector-free areas. Importantly, Ae. j. japonicus could be a relevant vector spreading the disease into new areas, indicating the need for security measures in areas where the mosquito is distributed or where it may be introduced.

scholarly journals Genotype 1 Japanese encephalitis virus predominates in nature in China

2019 ◽  
Author(s):  
Nan Shao ◽  
Shihong Fu ◽  
Fan Li ◽  
Weijia Zhang ◽  
Qianying Wang ◽  
...  
Keyword(s):  
Japanese Encephalitis Virus ◽  
Real Time ◽  
Japanese Encephalitis ◽  
Mosquito Species ◽  
Encephalitis Virus ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Principal Vector ◽  
Asian Pacific Region ◽  
Asian Pacific

AbstractIntroductionJapanese encephalitis virus (JEV), in the genus Flavivirus, family Flaviviridae, is the leading cause of viral encephalitis in the Asian-Pacific region. JEV has a wide range of vector hosts, including mosquitoes, swine, and wading birds. Culex species, especially Culex tritaeniorhynchus, are the main vectors for JEV transmission. JEV has been classified into five genotypes (G1–G5). JEV G1, G3, and G5 isolates have been found in China.MethodsMore than 200,000 mosquitoes collected in 14 provinces in China from 2004 to 2016 were examined for JEV using a TaqMan real-time RT-PCR assay. The JEV envelope (E) gene was sequenced from positive pools. The nucleic acid sequences were analyzed and aligned using ClustalX ver. 2.0. Representative JEV envelope (E) gene sequences were downloaded from GenBank and compared with the newly obtained JEV sequences. MEGA 5.05 was used to generate a phylogenetic tree based on the JEV sequences.ResultsMore than 200,000 mosquitoes were divided into 3107 pools to test for JEV. Of the pools, 9.04% (281/3107) were positive. The JEV obtained from mosquitoes included three genotypes (G1, G3, and G5). JEV G1 was detected from different provinces during 2004–2016. G1 was the dominant genotype circulating in nature, comprising 98.93% (278/281). JEV G3 was detected in Yunnan and Chongqing Provinces before 2010; JEV G5 was detected only in Tibet. No pools were positive for JEV G2 and G4. C. tritaeniorhynchus was the major mosquito species and the principal vector for transmitting JEV in China. The results of the TaqMan real-time RT-PCR assay and phylogenetic analysis consistently indicated that all 50 newly identified JEV sequences belonged to JEV G1.ConclusionG1 is the main genotype of JEV circulating in nature in China. Some G3 and G5 were found, but no G2 or G4.Author summaryJapanese encephalitis virus (JEV) is a member of the genus Flavivirus, family Flaviviridae and is the major pathogen agent of Japanese encephalitis (JE) in the Asian-Pacific region. The fatality rate of JE is 20–30%. JEV consists of five genotypes (G1-G5). The predominant genotype was G3 before the 20thcentury. G1 and G3 co-circulated in China at the end of the 20thand early 21stcentury. JEV G1 is the youngest genotype and has gradually been found in many areas worldwide. Using a sensitive TaqMan real-time RT-PCR assay, this study examined 3107 pools of mosquito. The main genotype of Japanese encephalitis virus in China was G1, with some G3 and G5, but no G2 or G4. C. tritaeniorhynchus was the major mosquito species and the principal vector for transmitting JEV in China. TaqMan real-time RT-PCR assay and phylogenetic analysis consistently indicated that all 50 newly identified JEV sequences belonged to JEV G1.

Epidemiological concordance of Japanese encephalitis virus infection among mosquito vectors, amplifying hosts and humans in India

2012 ◽  
Vol 141 (1) ◽  
pp. 74-80 ◽  
Author(s):  
J. BORAH ◽  
P. DUTTA ◽  
S. A. KHAN ◽  
J. MAHANTA
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Human Case ◽  
Encephalitis Virus ◽  
Control Measures ◽  
Mosquito Vectors ◽  
Japanese Encephalitis Virus Infection ◽  
Kaplan Meier ◽  
Highly Correlated ◽  
Relationship Of

SUMMARYA temporal relationship of Japanese encephalitis virus (JEV) transmission in pigs, mosquitoes and humans revealed that sentinel pig seroconversions were significantly associated with human cases 4 weeks before (P = 0·04) their occurrence, highly correlated during the same time and 2 weeks before case occurrence (P < 0·001), and remained significantly correlated up to 2 weeks after human case occurrence (P < 0·01). JEV was detected in the same month in pigs and mosquitoes, and peaks of pig seroconversion were preceded by 1–2 months of peaks of infection in vectors. Kaplan–Meier analysis indicated that detection of JEV-positive mosquitoes was significantly associated with the median time to occurrence of seroconversion in pigs (P < 0·05). This study will not only help in predicting JEV activity but also accelerate timely vector control measures and vaccination programmes for pigs and humans to reduce the Japanese encephalitis risk in endemic areas.

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