Comparison of the dynamics of Japanese encephalitis virus circulation in sentinel pigs between a rural and a peri-urban setting in Cambodia

Francesco, Juliette Di; Choeung, Rithy; Peng, Borin; Pring, Long; Pang, Senglong; Duboz, Raphaël; Ong, Sivuth; Sorn, San; Tarantola, Arnaud; Fontenille, Didier; Duong, Veasna; Dussart, Philippe; Chevalier, Véronique; Cappelle, Julien

doi:10.1371/journal.pntd.0006644

Cited by 26 publications

(41 citation statements)

References 41 publications

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“…Pigs act as an amplifier host of JEV, thus can be a key suspect of spreading infection to human living in close proximity [4]. The detection of JEV in pigs was reported earlier from Cambodia, Singapore, Vietnam, Australia, Japan, China, Thailand, Laos, Indonesia, India etc (Fig 6) [22, 34-42], however the studies on pigs for the presence of JE virus and its genotypes in circulation among pigs in India are limited [19]. Hence, the current investigation was mainly focused on the JE virus detection in pig serum and tonsil in three different JE endemic states of India namely Odisha, Assam and Manipur.…”

Section: Discussionmentioning

confidence: 94%

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Molecular epidemiology of Japanese Encephalitis Virus in pig population of Odisha, Assam and Manipur states of India

Datey

Singh²,

Rajkhowa

et al. 2019

Preprint

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AbstractJapanese encephalitis virus (JEV) comes under the family Flaviviridae and genus flavivirus. It predominantly infects the children under the age of 10 years and the case fatality rate can stretch out as high as 30%. Pigs act as reservoir and amplifying intermediate host for JEV. Recent report suggested longer persistence of JEV in tonsil than in circulation of experimentally infected pigs. The current investigation was conducted to understand the prevalence and molecular epidemiology of JEV infection in pigs in three different geographical sites in India (Odisha, Assam and Manipur). Serum samples were tested by ELISA and RT-PCR for detection of JEV, while only RT-PCR was done in case of tonsils tissues collected from pigs slaughtered in abattoir. Prevalence of JEV was highest in Manipur (25.45% in serum and 10.08% in tonsil) but lower in Assam (3.75% in serum and 0% in tonsils) and Odisha (1.49% in serum and 3.7% in tonsils). The percentage of sero-positivity was found to be 3.75% of IgM and 9.9% of IgG in Assam and Odisha respectively. Genotype III (GIII) of JEV was the dominant genotype and sporadic mutations of S83G, H76P, E78Q, C55S, and S64W along with two consistent mutations V46S and V51I were observed in all the GIII strains. Analysis of the E gene sequence revealed a single mutation, S118N in the GI strain. Older pigs (above 7 months) were found to be infected relatively more (8.6%) than younger pigs (age group 3-7 months). In conclusion, the high JE virus infection rate of pig in the current locations suggests the need for continuous surveillance of this virus in pigs which will ultimately help to adopt an effective control strategy to prevent the spread of JE infection to human.Author summaryJapanese encephalitis is one of the contributing factors in acute encephalitis syndrome cases reported across India as well as Asia. Primarily young naive human population are affected with JEV. The death rate can be as high as 30% and in about 30%-50% surviving population paralysis, brain damage or other serious permanent sequelae may be observed. The viral load gets amplified in pigs and thus plays a crucial role in transmitting the infection in human communities living in close proximity to pig dwelling. The current study was conducted to demonstrate prevalence of JEV in pig population of three geographical regions of India viz. the States of Odisha, Assam and Manipur that have reported JE outbreaks in human population. The current study demonstrates that the rate of infection is 3.28% among pigs in Manipur followed by Assam and Odisha. GIII was found to be the most predominant JEV genotype, while only one GI genotype strain was detected from Odisha region. These findings suggested the need of continuous surveillance of this virus in pigs and proper implementation of human and animal vaccination programme to control the infection.

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Section: Discussionmentioning

confidence: 94%

“…The main cause of viral encephalitis in Asia is JEV. The transmission of JEV is endemic in around 24 countries of South East Asia and Western Pacific regions [22]. More than 3 billion people are at risk of JEV infection with approximately 68,000 clinical cases reported every year [23].…”

Section: Introductionmentioning

confidence: 99%

Molecular epidemiology of Japanese Encephalitis Virus in pig population of Odisha, Assam and Manipur states of India

Datey

Singh²,

Rajkhowa

et al. 2019

Preprint

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“…B) was mostly influenced by vaccination ( v ), which generated about 40% of the total variance. The interaction between the vector population size (η) and the vector to host ratio ( φ ), contributed a significant part of total variance (15%). The influence of other parameters was much lower.…”

Section: Resultsmentioning

confidence: 99%

“…If the newly emerged female becomes infectious 15 days after emergence, it will remain infectious between 6 days (lifespan of 21 days) and 15 days (lifespan of 30 days). The average of the four preceding values (14, 21, 6, 15), 14 days, was considered the average duration of I state in vectors. Considering the minor role of direct transmission in disease dynamic (61) a consecutive duration of 14 days with less than 1 viremic pig ( I state) would result, on average, in the death of all the infectious vectors, without any new infection of susceptible mosquitoes.…”

Section: Methodsmentioning

confidence: 99%

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Modelling and assessment of combining gilt vaccination, vector control and pig herd management to control Japanese Encephalitis virus transmission in Southeast Asia

Diallo

Chevalier

Cappelle

et al. 2018

Preprint

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26Despite existence of human vaccines, Japanese Encephalitis (JE) remains a prominent public health 27 problem in Southeast Asia (SEA). JE is caused by a Flavivirus which is transmitted between pigs, the main 28 amplifying hosts, by Culex mosquito bites. Therefore, sow vaccination, pig herd management and vector 29 control -or a combination of these three potential control measures, might constitute additional control 30 measures contributing to reduce JE health impact in humans, and economic losses in pig farms. We built a 31 deterministic metapopulation model, combining a pig and a Culex mosquito vector population, to represent 32 JE virus (JEV) transmission dynamic within a pig herd. The dynamic of the epidemiological systems resulted 33 from an infectious process, operating in continuous time, combined with the pig breeding process that was 34 modeled based on discrete events occurring instantaneously. We used this model to simulate JEV 35 transmission within a continuum of plausible pig breeding systems encountered in SEA, ranging from 36 backyards to semi-commercial systems. We then analyzed the joint effects of the three tested control 37 measures, namely sow vaccination, pig herd management and vector control, on several indicators 38 characterizing (i) the ability of different pig breeding systems to be simultaneously profitable and allow JEV 39 eradication in the herd, (ii) the impact of JE on pig production and the profitability of gilt vaccination, and 40 (iii) the risk for human beings living in the vicinity of pig herds and/or near pig slaughterhouses. According 41 to our model, herd management has no effect on JEV circulation. Vector control alone is a major control tool 42 but shows paradoxical effects that should be considered in any mosquito based control strategy. Combining 43 sow vaccination and vector control could be an alternative or an additional measure to human vaccination to 44 efficiently reduce both JE incidence in humans and the economic impact of JE infection on pig farms. 45 Author summary 46 Japanese Encephalitis (JE) still has an important impact on human health in Southeast Asia. Human 47 vaccination is an efficient tool to protect humans but it may not be effective against emerging strains, and 48 poor or remote population may not be able to afford it. Severe outbreaks still occur. JE virus (JEV) is 49 primarily transmitted between pigs and mosquitoes. When infected after sexual maturity, pigs show 50 reproduction disorders leading to economic losses. We propose a modelling approach to investigate the joint 51 effect of three additional control measures, namely sow vaccination, vector control, and pig herd 52 management on JEV transmission dynamic, risk for humans and pigs, and pig breeding sustainability.3 53 According to our results, vector control, associated or not with sow vaccination, may be an efficient tool to 54 reduce JE incidence in both human and pigs. 55

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Adults in Northwest China experienced the largest outbreak of Japanese encephalitis in history 10 years after the Japanese encephalitis vaccine was included in the national immunization program: A retrospective epidemiological study

Zhang

Jin

et al. 2023

Journal of Medical Virology

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Mainland China included Japanese encephalitis (JE) vaccine in the national immunization program in 2008 to control the JE epidemic. However, Gansu province in Western China experienced the largest JE outbreak since 1958 in 2018.We conducted a retrospective epidemiological study to explore the causes of this outbreak. We found that adults aged ≥20 years (especially those in rural areas) were the main JE cases in Gansu Province, with a significant increase in the JE incidence in older adults aged ≥60 years in 2017 and 2018. In addition, JE outbreaks in Gansu Province were mainly located in the southeastern region, while the temperature and precipitation in Gansu Province were gradually increasing in recent years, which made the JE epidemic areas in Gansu Province gradually spread to the western of Gansu Province. We also found that adults aged ≥20 years in Gansu Province had lower JE antibody positivity than children and infants, and the antibody positivity rate decreased with age. In the summer of 2017 and 2018, the density of mosquitoes (mainly the Culex tritaeniorhynchus) in Gansu Province was significantly higher than in other years, and the genotype of JEV was mainly Genotype-G1.Therefore, in the future JE control in Gansu Province, we need to strengthen JE vaccination for adults. Moreover, strengthening mosquito surveillance can provide early warning of JE outbreaks and the spread of epidemic areas in Gansu Province.At the same time, strengthening JE antibody surveillance is also necessary for JE control.

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Comparison of the dynamics of Japanese encephalitis virus circulation in sentinel pigs between a rural and a peri-urban setting in Cambodia

Cited by 26 publications

References 41 publications

Molecular epidemiology of Japanese Encephalitis Virus in pig population of Odisha, Assam and Manipur states of India

Molecular epidemiology of Japanese Encephalitis Virus in pig population of Odisha, Assam and Manipur states of India

Modelling and assessment of combining gilt vaccination, vector control and pig herd management to control Japanese Encephalitis virus transmission in Southeast Asia

Adults in Northwest China experienced the largest outbreak of Japanese encephalitis in history 10 years after the Japanese encephalitis vaccine was included in the national immunization program: A retrospective epidemiological study

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