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1.
BMC Infect Dis ; 21(1): 1172, 2021 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-34809606

RESUMO

BACKGROUND: Although a vaccination campaign has been conducted since 2004, Japanese encephalitis (JE) is still a public health problem in Guizhou, one of the provinces with the highest incidence of JE in China. The aim of this study was to understand the spatiotemporal distribution of JE and its relationship with environmental factors in Guizhou Province in the post-vaccination era, 2004-2016. METHODS: We collected data on human JE cases in Guizhou Province from 2004 to 2016 from the national infectious disease reporting system. A Poisson regression model was used to analyze the relationship between JE occurrence and environmental factors amongst counties. RESULTS: Our results showed that the incidence and mortality of JE decreased after the initiation of vaccination. JE cases were mainly concentrated in preschool and school-age children and the number of cases in children over age 15 years was significantly decreased compared with the previous 10 years; the seasonality of JE before and after the use of vaccines was unchanged. JE incidence was positively associated with cultivated land and negatively associated with gross domestic product (GDP) per capita, vegetation coverage, and developed land. In areas with cultivated land coverage < 25%, vegetation coverage > 55%, and urban area coverage > 25%, the JE risk was lower. The highest JE incidence was among mid-level GDP areas and in moderately urbanized areas. CONCLUSIONS: This study assessed the relationship between incidence of JE and environmental factors in Guizhou Province. Our results highlight that the highest risk of JE transmission in the post-vaccination era is in mid-level developed areas.


Assuntos
Encefalite Japonesa , Vacinas contra Encefalite Japonesa , Adolescente , Criança , Pré-Escolar , China/epidemiologia , Encefalite Japonesa/epidemiologia , Encefalite Japonesa/prevenção & controle , Humanos , Programas de Imunização , Vacinação
2.
Ann Glob Health ; 87(1): 103, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34722167

RESUMO

Background and objects: The study aimed to evaluate the long-term neurological sequelae and the disease burden of JE in Gansu, China. Methods: JE patients were included as study population from 2005-2011 in Gansu, and a follow-up survey was conducted in 2007-2014. Pair-matched healthy individuals were selected as controls. All subjects underwent a neurological examination and intelligence quotient (IQ) and memory quotient (MQ) assessments. Then, the disability-adjusted life years (DALYs), and direct and indirect medical expenses were systematic assessed. Results: Forty-four point seven percent of the JE patients had objective neurological deficits, compared with 2.4% of controls. Subnormal intelligence was found in 21.2% of JE subjects, compared with 1.2% control who exhibited a mildly reduced IQ. Abnormal MQ scores were noted in 56.3% JE subjects, compared with only 12.7% controls. Prevalence of each sequelae caused by JE were significantly higher in adults than in younger subjects. Furthermore, median DALY lost due to JE was 9.2 per subject. Median economic cost of JE was approximately $2776.6 per subject and significantly higher in adults than in younger subjects. Findings and Conclusions: JE patients suffered from severe neurological sequelae and high disease burden, resulting in a significant downstream burden for both the patients (especially adults) and the healthcare system.


Assuntos
Encefalite Japonesa , Adulto , China/epidemiologia , Efeitos Psicossociais da Doença , Progressão da Doença , Encefalite Japonesa/diagnóstico , Encefalite Japonesa/epidemiologia , Humanos , Anos de Vida Ajustados por Qualidade de Vida
3.
Lancet ; 398(10301): 675-684, 2021 08 21.
Artigo em Inglês | MEDLINE | ID: mdl-34384540

RESUMO

BACKGROUND: Typhoid fever remains a major cause of morbidity and mortality in low-income and middle-income countries. Vi-tetanus toxoid conjugate vaccine (Vi-TT) is recommended by WHO for implementation in high-burden countries, but there is little evidence about its ability to protect against clinical typhoid in such settings. METHODS: We did a participant-masked and observer-masked cluster-randomised trial preceded by a safety pilot phase in an urban endemic setting in Dhaka, Bangladesh. 150 clusters, each with approximately 1350 residents, were randomly assigned (1:1) to either Vi-TT or SA 14-14-2 Japanese encephalitis (JE) vaccine. Children aged 9 months to less than 16 years were invited via parent or guardian to receive a single, parenteral dose of vaccine according to their cluster of residence. The study population was followed for an average of 17·1 months. Total and overall protection by Vi-TT against blood culture-confirmed typhoid were the primary endpoints assessed in the intention-to-treat population of vaccinees or all residents in the clusters. A subset of approximately 4800 participants was assessed with active surveillance for adverse events. The trial is registered at www.isrctn.com, ISRCTN11643110. FINDINGS: 41 344 children were vaccinated in April-May, 2018, with another 20 412 children vaccinated at catch-up vaccination campaigns between September and December, 2018, and April and May, 2019. The incidence of typhoid fever (cases per 100 000 person-years) was 635 in JE vaccinees and 96 in Vi-TT vaccinees (total Vi-TT protection 85%; 97·5% CI 76 to 91, p<0·0001). Total vaccine protection was consistent in different age groups, including children vaccinated at ages under 2 years (81%; 95% CI 39 to 94, p=0·0052). The incidence was 213 among all residents in the JE clusters and 93 in the Vi-TT clusters (overall Vi-TT protection 57%; 97·5% CI 43 to 68, p<0·0001). We did not observe significant indirect vaccine protection by Vi-TT (19%; 95% CI -12 to 41, p=0·20). The vaccines were well tolerated, and no serious adverse events judged to be vaccine-related were observed. INTERPRETATION: Vi-TT provided protection against typhoid fever to children vaccinated between 9 months and less than 16 years. Longer-term follow-up will be needed to assess the duration of protection and the need for booster doses. FUNDING: The study was funded by the Bill & Melinda Gates Foundation.


Assuntos
Polissacarídeos Bacterianos/administração & dosagem , Toxoide Tetânico/uso terapêutico , Febre Tifoide/prevenção & controle , Vacinas Tíficas-Paratíficas/administração & dosagem , Vacinação , Vacinas Conjugadas/administração & dosagem , Adolescente , Bangladesh/epidemiologia , Criança , Pré-Escolar , Países em Desenvolvimento , Encefalite Japonesa/epidemiologia , Feminino , Humanos , Lactente , Vacinas contra Encefalite Japonesa/administração & dosagem , Masculino , Salmonella typhi/imunologia , Toxoide Tetânico/imunologia , Febre Tifoide/epidemiologia , Febre Tifoide/imunologia
4.
Vaccine ; 39(35): 4973-4978, 2021 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-34325931

RESUMO

BACKGROUND: Japanese encephalitis virus (JEV) remains the major etiology of encephalitis throughout Asia. In India, the state of Assam alone contributes more than one-third of the national burden of JE. Between 2011 and 2014, a single dose of JE vaccine SA 14-14-2 (LAJEV) was administered among adults aged 15-65 years residing in Sivasagar and Dibrugarh districts of Assam, India. We monitored the trend of JE incidence between 2009 and 2018 using JE surveillance data, estimated the long-term effectiveness of the single dose of LAJEV and estimated the coverage of JE vaccine in two districts. METHODS: We compared the JE vaccination status of laboratory-confirmed hospitalized JE patients (case) and age, sex and locality matched healthy individuals (controls) to estimate the effectiveness of single dose of JE vaccine. We used surveillance data for 2009-2018 to calculate the incidence of JE among adults. We conducted a community-based survey to estimate the coverage of JE vaccine in the two districts. RESULTS: A total of 452 laboratory-confirmed JE case-patients and 904 matched healthy controls were enrolled in the study between 2012 and 2018. The effectiveness of a single dose of JE vaccine over the 7-year period was 77.0 (95% CI: 67.0-83.0). Vaccine effectiveness decreased from 91% (95% CI: 73.0-97.0) in first year of vaccination to 71% (95% CI: 21.0-90.0) at six years post-vaccination. The incidence of adults JE cases declined from 10.5 per 100,000 in the pre-vaccination period to 5.7 per 100,000 in the years following vaccination. The coverage of vaccine among adults in two districts was 40.1% (36.8-43.5). CONCLUSIONS: A single dose of JE vaccine offered adequate protection for at least six years. Conducting mass vaccination campaigns periodically would further reduce the incidence of JE in endemic districts in Assam.


Assuntos
Vírus da Encefalite Japonesa (Espécie) , Encefalite Japonesa , Vacinas contra Encefalite Japonesa , Adulto , Encefalite Japonesa/epidemiologia , Encefalite Japonesa/prevenção & controle , Humanos , Programas de Imunização , Índia/epidemiologia
5.
Viruses ; 13(6)2021 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-34208737

RESUMO

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.


Assuntos
Vírus da Encefalite Japonesa (Espécie) , Encefalite Japonesa/transmissão , Encefalite Japonesa/virologia , Mosquitos Vetores/virologia , Animais , Vetores de Doenças , Encefalite Japonesa/epidemiologia , Geografia Médica , Saúde Global , Humanos , Mosquitos Vetores/classificação , Vigilância da População
6.
Math Biosci Eng ; 18(4): 3046-3072, 2021 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-34198375

RESUMO

Japanese encephalitis (JE) is a mosquito-borne neglected tropical disease. JE is mostly found in rural areas where people usually keep cattle at home for their needs. Cattle in households reduce JE virus infections since they distract vectors and act as a dead-end host for the virus. However, the presence of cattle introduces risk of leptospirosis infections in humans. Leptospirosis is a bacterial disease that spreads through direct or indirect contact of urine of the infected cattle. Thus, cattle have both positive and negative impacts on human disease burden. This study uses a mathematical model to study the joint dynamics of these two diseases in the presence of cattle and to identify the net impact of cattle on the annual disease burden in JE-prevalent areas. Analysis indicates that the presence of cattle helps to reduce the overall disease burden in JE-prevalent areas. However, this reduction is dominated by the vector's feeding pattern. To the best of our knowledge, this is the first study to examine the joint dynamics of JE and leptospirosis.


Assuntos
Vírus da Encefalite Japonesa (Espécie) , Encefalite Japonesa , Leptospirose , Animais , Bovinos , Efeitos Psicossociais da Doença , Encefalite Japonesa/epidemiologia , Encefalite Japonesa/veterinária , Leptospirose/epidemiologia , Leptospirose/veterinária
7.
PLoS Negl Trop Dis ; 15(6): e0009505, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34153039

RESUMO

BACKGROUND: Japanese encephalitis (JE) is a mosquito-borne disease and associated with high mortality and disability rate among symptomatic cases. In the absence of local data, this study estimated the economic burden and the disability-adjusted life years (DALYs) due to JE in Zhejiang Province, China during 2013-2018, to increase disease awareness and provide evidence for effective health policy. METHODOLOGY/PRINCIPLE FINDINGS: We merged multiple data sources, including National Notifiable Disease Registry System (NNDRS), patient interviews and medical records from corresponding hospitals for JE cases which occurred during 2013-2018 in Zhejiang Province. Direct costs were extracted from hospitals' billing systems and patient interviews. Indirect costs and disease burden were calculated based on questionnaire survey from patient interviews and follow-up assessment by general practitioners. Given under-reporting, an expansion factor (EF) was applied to extrapolate the JE burden to the provincial level. The total economic burden of JE during 2013-2018 was estimated at US $12.01 million with an EF = 3. Of this, $8.32 million was due to direct economic cost and $3.69 million to indirect cost. The disease burden of JE was 42.75 DALYs per million population (28.44 YLD, 14.28 YLL) according to the 1990 Global Burden of Disease (GBD 1990) methodology and 80.01 DALYs (53.67YLD, 26.34YLL) according to the GBD 2010 methodology. Sensitivity analysis demonstrated that the overall economic burden varied from US$ 1.73-36.42 million. The greatest variation was due to the prognosis of illness (-85.57%-203.17%), followed by occupation (-34.07%-134.12%) and age (-72.97%-47.69%). CONCLUSIONS/SIGNIFICANCE: JE imposes a heavy burden for families and society in Zhejiang Province. This study provides comprehensive empirical estimates of JE burden to increase awareness and strengthen knowledge of the public. These data may support provincial level public health decision making for prevention and control of JE. Ongoing surveillance for acute meningitis and encephalitis syndrome (AEMS) in sentinel hospitals, is needed to further refine estimates of JE burden.


Assuntos
Efeitos Psicossociais da Doença , Encefalite Japonesa/economia , Custos de Cuidados de Saúde/estatística & dados numéricos , Adolescente , Adulto , Criança , Pré-Escolar , China/epidemiologia , Vírus da Encefalite Japonesa (Espécie)/imunologia , Encefalite Japonesa/epidemiologia , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Anos de Vida Ajustados por Qualidade de Vida
8.
PLoS Negl Trop Dis ; 15(6): e0009497, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34153065

RESUMO

Japanese encephalitis (JE) is the major cause of viral encephalitis (VE) in most Asian-Pacific countries. In Vietnam, there is no nationwide surveillance system for JE due to lack of medical facilities and diagnoses. Culex tritaeniorhynchus, Culex vishnui, and Culex quinquefasciatus have been identified as the major JE vectors in Vietnam. The main objective of this study was to forecast a risk map of Culex mosquitoes in Hanoi, which is one of the most densely populated cities in Vietnam. A total of 10,775 female adult Culex mosquitoes were collected from 513 trapping locations. We collected temperature and precipitation information during the study period and its preceding month. In addition, the other predictor variables (e.g., normalized difference vegetation index [NDVI], land use/land cover and human population density), were collected for our analysis. The final model selected for estimating the Culex mosquito abundance included centered rainfall, quadratic term rainfall, rice cover ratio, forest cover ratio, and human population density variables. The estimated spatial distribution of Culex mosquito abundance ranged from 0 to more than 150 mosquitoes per 900m2. Our model estimated that 87% of the Hanoi area had an abundance of mosquitoes from 0 to 50, whereas approximately 1.2% of the area showed more than 100 mosquitoes, which was mostly in the rural/peri-urban districts. Our findings provide better insight into understanding the spatial distribution of Culex mosquitoes and its associated environmental risk factors. Such information can assist local clinicians and public health policymakers to identify potential areas of risk for JE virus. Risk maps can be an efficient way of raising public awareness about the virus and further preventive measures need to be considered in order to prevent outbreaks and onwards transmission of JE virus.


Assuntos
Distribuição Animal , Culex , Mosquitos Vetores , Animais , Ecossistema , Vírus da Encefalite Japonesa (Espécie) , Encefalite Japonesa/epidemiologia , Feminino , Humanos , Chuva , Fatores de Risco , Temperatura , Vietnã/epidemiologia
9.
Indian Pediatr ; 58(9): 846-849, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34016800

RESUMO

OBJECTIVE: To describe the long term morbidity and functional outcome of Japanese encephalitis in children. Methods: Laboratory-confirmed Japanese encephalitis cases were enrolled in the study from January, 2016 to September, 2017 and surviving cases were prospectively followed up for 2.5 years to document various morbidities. Outcome was functionally graded at discharge and during follow-up using Liverpool outcome score. Results: Out of 56 children enrolled, 10 (17.9%) died during hospital stay; severe sequelae was observed in 17 (30.4%) at discharge. At the end of study, among 37 children under follow-up, 23 (62.2%) recovered fully, 2 (5.4%) showed minor sequelae, 3 (8.1%) had moderate sequelae, and 9 (24.3%) were left with severe sequelae. Common long term morbidities were abnormal behavior (n=10, 27%), post encephalitic epilepsy (n=8, 21.6%), poor scholastic performance (n=8, 21.6%) and residual motor deficit (n=7, 18.9%). Improvement of morbidities was noted mostly within initial 1 year of follow-up. CONCLUSION: More than half of the Japanese encephalitis survivors recovered fully, most within the first year after discharge.


Assuntos
Encefalite Japonesa , Encefalite , Criança , Encefalite Japonesa/epidemiologia , Humanos , Lactente , Tempo de Internação , Morbidade , Estudos Prospectivos
10.
Infect Dis Poverty ; 10(1): 57, 2021 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-33902684

RESUMO

BACKGROUND: Mosquito-based arbovirus surveillance can serve as an early warning in evaluating the status of mosquito-borne virus prevalence and thus prevent local outbreaks. Although Tengchong County in Yunnan Province-which borders Myanmar-is abundant and diverse in mosquitoes, very few mosquito-based arbovirus investigations have been conducted in the recent decade. Herein, this study aims to evaluate the presence and the diffusion of mosquito-borne pathogens, currently prevalent in this region. METHODS: We collected 9486 mosquitoes, representing eight species, with Culex tritaeniorhynchus and Anopheles sinensis as the dominant species, during high mosquito activity seasons (July-October) in Tengchong, in 2018. Samples collected from 342 pools were tested using reverse-transcription PCR to determine the species, distribution, and infection rates of virus and parasite, and further analyze their genotypes, phylogenetic relationships, infection rate, and potential pathogenicity. RESULTS: Fifteen Japanese encephalitis virus (JEV) strains from Cx. tritaeniorhynchus pools were detected. Seven strains of insect-specific flaviviruses (ISFVs), including two Aedes flavivirus (AeFV) and Yunnan Culex flavivirus strains each, one Culex theileri flavivirus, Yamadai flavivirus (YDFV) and Anopheles-associated flavivirus (AAFV) strains each were detected in Aedes albopictus, Cx. tritaeniorhynchus, Cx. vagans, Cx. pseudovihnui, and An. sinensis pools, respectively. The whole-genome was successfully amplified in one strain of JEV and AeFV each. Phylogenetic analysis using the E gene placed all the newly detected JEV strains into the GI-b genotype. They showed highly nucleotide identities, and were most closely related to the strain detected in Tengchong in 2010. The comparison of the E protein of JEV strains and vaccine-derived strain, showed six amino residue differences. The bias-corrected maximum likelihood estimation values (and 95% confidence interval) for JEV in Cx. tritaeniorhynchus collected in Tengchong in 2018 were 2.4 (1.4-3.9). CONCLUSIONS: A potential Japanese encephalitis epidemic focus with the abundance of host mosquitoes and high JEV infection rate was observed in Tengchong. In addition, at least five species of ISFVs co-circulate in this area. This study highlights the importance of widespread and sustained mosquito-based arbovirus surveillance in local areas to prevent the transmission of JEV, and other emerging/re-emerging mosquito-borne pathogens.


Assuntos
Anopheles , Encefalite Japonesa , Epidemias , Flavivirus , Vírus , Animais , China/epidemiologia , Encefalite Japonesa/epidemiologia , Flavivirus/genética , Epidemiologia Molecular , Mianmar/epidemiologia , Filogenia
11.
Indian J Med Res ; 153(3): 388-393, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33907003

RESUMO

Background & Objectives: Japanese encephalitis/acute encephalitis syndrome (JE/AES) is one of the major zoonotic arbodiseases that has a significant effect on human and animal health. Though many studies have been published on the epidemiology and transmission mechanisms of JE/AES, but there is little evidence on health system preparedness, including community-based engagement. This study was undertaken to explore a multi-stakeholder perspective on health system preparedness for the prevention of JE/AES in a tribal district of Odisha, India. Methods: This study was conducted at Malkangiri district of Odisha. A total of nine focus group discussions (FGDs) among women having under-five children, community volunteers, and community health workers (CHWs), and 20 in-depth-interviews (IDIs) among community leaders, healthcare providers, and programme managers were conducted. The FGDs and IDIs were digitally recorded, transcribed, translated and analysed using content analysis approach. Results: Health system preparedness for the prevention of JE/AES was improved, including effective vector management, implementation of the surveillance system, and vaccination programme. The JE vaccine was introduced under Universal Immunization Programme in Odisha in 2016. Behavioural Change Communication activities were provided with the support of community volunteers on Village Health Nutrition and Sanitation Day (VHNSD) under Gaon Kalyan Samiti (GKS) platforms. The CHWs were actively involved in vector management and raising sanitation and hygiene awareness. Interpretation & conclusions: Community participation and coordination between different stakeholders have a significant impact on the successful implementation of the programme. It was suggested that there was a need for a sustainability approach to active participation, orientation and capacity building training among CHWs and community volunteers to successfully implement the programme.


Assuntos
Encefalopatia Aguda Febril , Encefalite Japonesa , Animais , Criança , Participação da Comunidade , Encefalite Japonesa/epidemiologia , Encefalite Japonesa/prevenção & controle , Feminino , Humanos , Programas de Imunização , Índia/epidemiologia
13.
PLoS One ; 16(3): e0247980, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33657174

RESUMO

Japanese encephalitis (JE) is an acute infectious disease caused by the Japanese encephalitis virus (JEV) and is transmitted by mosquitoes. Meteorological conditions are known to play a pivotal role in the spread of JEV. In this study, a zero-inflated generalised additive model and a long short-term memory model were used to assess the relationship between the meteorological factors and population density of Culex tritaeniorhynchus as well as the incidence of JE and to predict the prevalence dynamics of JE, respectively. The incidence of JE in the previous month, the mean air temperature and the average of relative humidity had positive effects on the outbreak risk and intensity. Meanwhile, the density of all mosquito species in livestock sheds (DMSL) only affected the outbreak risk. Moreover, the region-specific prediction model of JE was developed in Chongqing by used the Long Short-Term Memory Neural Network. Our study contributes to a better understanding of the JE dynamics and helps the local government establish precise prevention and control measures.


Assuntos
Vírus da Encefalite Japonesa (Espécie)/isolamento & purificação , Encefalite Japonesa/epidemiologia , Animais , Culex/virologia , Encefalite Japonesa/transmissão , Humanos , Umidade , Conceitos Meteorológicos , Mosquitos Vetores/virologia , Prevalência , Fatores de Risco , Estações do Ano , Temperatura
14.
Sci Rep ; 11(1): 6133, 2021 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-33731761

RESUMO

Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, is the main cause of viral encephalitis in Asia. However, with changing climate JEV has the potential to emerge in novel temperate regions. Here, we have assessed the vector competence of the temperate mosquito Culex pipiens f. pipiens to vector JEV genotype III at temperatures representative of those experienced, or predicted in the future during the summer months, in the United Kingdom. Our results show that Cx. pipiens is susceptible to JEV infection at both temperatures. In addition, at 25 °C, JEV disseminated from the midgut and was recovered in saliva samples, indicating the potential for transmission. At a lower temperature, 20 °C, following an incubation period of fourteen days, there were reduced levels of JEV dissemination and virus was not detected in saliva samples. The virus present in the bodies of these mosquitoes was restricted to the posterior midgut as determined by microscopy and viable virus was successfully recovered. Apart from the influence on virus dissemination, mosquito mortality was significantly increased at the higher temperature. Overall, our results suggest that temperature is a critical factor for JEV vector competence and infected-mosquito survival. This may in turn influence the vectorial capacity of Cx. pipiens to vector JEV genotype III in temperate areas.


Assuntos
Culex/virologia , Vírus da Encefalite Japonesa (Espécie)/isolamento & purificação , Encefalite Japonesa/epidemiologia , Mosquitos Vetores/virologia , Animais , Temperatura , Reino Unido
15.
Int J Infect Dis ; 102: 344-351, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33127505

RESUMO

BACKGROUND: Findings were published in 2015 that highlighted the endemicity of Japanese Encephalitis (JE) in the Philippines. The policymakers responded by conducting an immunization campaign and strengthening the surveillance system. Using data on the revitalized surveillance system, the epidemiology of JE in the country was updated. METHODS: Electronic databases were searched, and conference proceedings related to JE in the Philippines were identified until 31 December 2018. Surveillance data from 01 January 2014 to 31 December 2017 were used. The 2015 population census was used to estimate the national and regional incidence for children aged <15 years. RESULTS: Four studies reported the seroprevalence of JE in the Philippines, which showed increasing seroprevalence with increasing age. Seroprevalence rates were from 0% for infants (aged <1 year) to 65.7% in adolescents (12-18 years) before the immunization campaign. Among five studies on the clinical profile of JE, case fatality ranged from 0 to 21.1% and neurologic sequelae ranged from 5.2 to 81.8% of diagnosed cases. In the surveillance data, JE cases peaked annually from July to October, coinciding with the wet season. The national incidence was estimated at a minimum of 0.7 JE cases/100,000 among children aged <15 years, but higher rates were seen in the northern regions of the country. CONCLUSION: Improved surveillance affirmed the burden of JE in the Philippines. A subnational immunization campaign in April 2019 was conducted in the northern regions of the country. This paper highlights the importance of including the JE vaccine in the immunization program and sustained high-quality surveillance to monitor its impact on JE control.


Assuntos
Encefalite Japonesa/epidemiologia , Programas de Imunização , Vacinas contra Encefalite Japonesa/administração & dosagem , Bases de Dados Factuais , Encefalite Japonesa/prevenção & controle , Humanos , Incidência , Vacinas contra Encefalite Japonesa/imunologia , Filipinas/epidemiologia , Estudos Soroepidemiológicos
16.
PLoS Negl Trop Dis ; 14(12): e0008986, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33370301

RESUMO

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.


Assuntos
Aedes/virologia , Culex/virologia , Vírus da Encefalite Japonesa (Espécie)/crescimento & desenvolvimento , Vírus da Encefalite Japonesa (Espécie)/isolamento & purificação , Encefalite Japonesa/transmissão , Mosquitos Vetores/virologia , Animais , Ásia/epidemiologia , Linhagem Celular , Chlorocebus aethiops , Vírus da Encefalite Japonesa (Espécie)/genética , Encefalite Japonesa/epidemiologia , Genótipo , Humanos , Células Vero , Proteínas do Envelope Viral/genética
17.
F1000Res ; 9: 6, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33014343

RESUMO

Background: Japanese encephalitis (JE) is a mosquito-borne disease with high case fatality and no specific treatment. Little is known about the community's (especially parents/guardians of children) awareness regarding JE and its vaccine in Yangon region, which bears the highest JE burden in Myanmar. Methods: We conducted a community-based cross-sectional study in Yangon region (2019) to explore the knowledge and perception of parents/guardians of 1-15 year-old children about JE disease, its vaccination and to describe JE vaccine coverage among 1-15 year-old children. We followed multi-stage random sampling (three stages) to select the 600 households with 1-15 year-old children from 30 clusters in nine townships. Analyses were weighted (inverse probability sampling) for the multi-stage sampling design. Results: Of 600 parents/guardians, 38% exhibited good knowledge of JE , 55% perceived JE as serious in  children younger than 15 years and 59% perceived the vaccine to be effective . Among all the children in the 600 households, the vaccination coverage was 97% (831/855). Conclusion: In order to reduce JE incidence in the community, focus on an intensified education program is necessary to sustain the high vaccine coverage in the community.


Assuntos
Encefalite Japonesa , Conhecimentos, Atitudes e Prática em Saúde , Vacinas contra Encefalite Japonesa/administração & dosagem , Cobertura Vacinal/estatística & dados numéricos , Adolescente , Adulto , Criança , Pré-Escolar , Estudos Transversais , Encefalite Japonesa/epidemiologia , Encefalite Japonesa/prevenção & controle , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Mianmar , Pais , Adulto Jovem
18.
F1000Res ; 9: 6, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33014342

RESUMO

Background: Japanese encephalitis (JE) is a mosquito-borne disease with high case fatality and no specific treatment. Little is known about the community's (especially parents/guardians of children) awareness regarding JE and its vaccine in Yangon region, which bears the highest JE burden in Myanmar. Methods: We conducted a community-based cross-sectional study in Yangon region (2019) to explore the knowledge and perception of parents/guardians of 1-15 year-old children about JE disease, its vaccination and to describe JE vaccine coverage among 1-15 year-old children. We followed multi-stage random sampling (three stages) to select the 600 households with 1-15 year-old children from 30 clusters in nine townships. Analyses were weighted (inverse probability sampling) for the multi-stage sampling design. Results: Of 600 parents/guardians, 38% exhibited good knowledge of JE , 55% perceived JE as serious in  children younger than 15 years and 59% perceived the vaccine to be effective . Among all the children in the 600 households, the vaccination coverage was 97% (831/855). Conclusion: In order to reduce JE incidence in the community, focus on an intensified education program is necessary to sustain the high vaccine coverage in the community.


Assuntos
Encefalite Japonesa , Conhecimentos, Atitudes e Prática em Saúde , Vacinas contra Encefalite Japonesa/administração & dosagem , Mosquitos Vetores/virologia , Cobertura Vacinal/estatística & dados numéricos , Adolescente , Adulto , Animais , Criança , Pré-Escolar , Estudos Transversais , Encefalite Japonesa/epidemiologia , Encefalite Japonesa/prevenção & controle , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Mianmar , Adulto Jovem
19.
PLoS One ; 15(10): e0238609, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33112881

RESUMO

INTRODUCTION: Although immune responses to the Japanese Encephalitis virus (JEV), and the dengue viruses (DENV) have a potential to modulate the immune responses to each other, this has been poorly investigated. Therefore, we developed an ELISA to identify JEV specific, DENV non cross-reactive antibody responses by identifying JEV specific, highly conserved regions of the virus and proceeded to investigate if the presence of JEV specific antibodies associate with dengue disease severity. METHODOLOGY AND RESULTS: 22 JEV specific peptides were identified from highly conserved regions of the virus and the immunogenicity and specificity of these peptides were assessed in individuals who were non-immune to JEV and DENV (JEV-DENV-, N = 30), those who were only immune to the JEV and not DENV (JEV+DENV-, N = 30), those who were only immune to DENV(JEV-DENV+, N = 30) and in those who were immune to both viruses (JEV+DENV+, N = 30). 7/22 peptides were found to be highly immunogenic and specific and these 7 peptides were used as a pool to further evaluate JEV-specific responses. All 30/30 JEV+DENV- and 30/30 JEV+DENV+ individuals, and only 3/30 (10%) JEV-DENV+ individuals responded to this pool. We further evaluated this pool of 7 peptides in patients following primary and secondary dengue infection during the convalescent period and found that the JEV-specific peptides, were unlikely to cross react with DENV IgG antibodies. We further compared this in-house ELISA developed with the peptide pool with an existing commercial JEV IgG assay to identify JEV-specific IgG following vaccination, and our in-house ELISA was found to be more sensitive. We then proceeded to investigate if the presence of JEV-specific antibodies were associated with dengue disease severity, and we found that those who had past severe dengue (n = 175) were significantly more likely (p<0.0001) to have JEV-specific antibodies than those with past non-severe dengue (n = 175) (OR 5.3, 95% CI 3.3 to 8.3). CONCLUSIONS: As our data show that this assay is highly sensitive and specific for detection of JEV-specific antibody responses, it would be an important tool to determine how JEV seropositivity modulate dengue immunity and disease severity when undertaking dengue vaccine trials.


Assuntos
Anticorpos Antivirais/sangue , Vírus da Encefalite Japonesa (Espécie)/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Sequência de Aminoácidos , Especificidade de Anticorpos , Criança , Sequência Conservada , Reações Cruzadas , Dengue/imunologia , Dengue/virologia , Vírus da Dengue/classificação , Vírus da Dengue/genética , Vírus da Dengue/imunologia , Vírus da Encefalite Japonesa (Espécie)/genética , Encefalite Japonesa/epidemiologia , Encefalite Japonesa/imunologia , Encefalite Japonesa/virologia , Ensaio de Imunoadsorção Enzimática/estatística & dados numéricos , Feminino , Voluntários Saudáveis , Humanos , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/imunologia , Sensibilidade e Especificidade , Estudos Soroepidemiológicos , Sorogrupo , Sri Lanka/epidemiologia , Vacinação , Proteínas Virais/genética , Proteínas Virais/imunologia , Adulto Jovem
20.
Am J Trop Med Hyg ; 103(6): 2442-2449, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33124540

RESUMO

Although previous studies have reported that meteorological factors might affect the risk of Japanese encephalitis (JE), the relationship between meteorological factors and JE remains unclear. This study aimed to evaluate the relationship between meteorological factors and JE and identify the threshold temperature. Daily meteorological data and JE surveillance data in Dazhou, Sichuan, were collected for the study period from 2005 to 2012 (restricting to May-October because of the seasonal distribution of JE). A distributed lag nonlinear model was used to analyze the lagged and cumulative effect of daily average temperature and daily rainfall on JE transmission. A total of 622 JE cases were reported over the study period. We found JE was positively associated with daily average temperature and daily rainfall with a 25-day lag and 30-day lag, respectively. The threshold value of the daily average temperature is 20°C. Each 5°C increase over the threshold would lead to a 13% (95% CI: 1-17.3%) increase in JE. Using 0 mm as the reference, a daily rainfall of 100 mm would lead to a 132% (95% CI: 73-311%) increase in the risk of JE. Japanese encephalitis is climate-sensitive; meteorological factors should be taken into account for the future prevention and control measure making, especially in a warm and rainy weather condition.


Assuntos
Encefalite Japonesa/epidemiologia , Encefalite Japonesa/transmissão , Umidade , Chuva , Temperatura , Adolescente , Adulto , Criança , Pré-Escolar , China/epidemiologia , Feminino , Humanos , Masculino , Conceitos Meteorológicos , Dinâmica não Linear
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