Japanese Encephalitis

2021 ◽  
Author(s):  
Wolfgang Bender

Japanese Encephalitis (JE) is an endemic vector-borne (mosquitoes) zoonotic flavivirus disease in Asia with severe neurological manifestations (case fatality rate CFR 20–30%; 30–50% of survivors with serious sequelae). Japanese Encephalitis Virus (JEV) is the leading cause of viral encephalitis in Asia and exposes an estimated 3 billion people to the risk of infection. Other regions of the world have conditions suiting JEV without circulation of the virus (yet). Most JEV infections are asymptomatic or only cause mild symptoms. 1 in 250 infections progresses to severe disease for which no specific treatment is yet available. Neutralizing antibodies develop after infection. In endemic areas this occurs usually during childhood followed by subclinical re-exposure with life-long immunity protecting against disease. Disease in adult populations in endemic areas is rare. General prevention includes avoidance of mosquito bites, e.g., repellents, long-sleeved clothes, coils and vaporizers. Vaccine prevention: Neutralizing antibodies (PRNT50 titer ≥ 1:10) is the correlate of protection. Vaccines currently used are live attenuated JE vaccines and recombinant chimeric JE vaccines (mostly in endemic countries) and cell culture-derived inactivated JE vaccines (travelers, endemic countries). As animal reservoirs of the JEV cannot be eradicated, universal vaccination of humans can control the disease in humans. Optimal JE control in endemic countries is limited by issues around vaccine supply, surveillance (burden of disease underestimation), and resource competition / prioritization.

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 6
Author(s):  
Pyae Phyo Kyaw ◽  
Hemant Deepak Shewade ◽  
Nang Thu Thu Kyaw ◽  
Khaing Hnin Phyo ◽  
Htar Htar Lin ◽  
...  

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.


2018 ◽  
Vol 12 (1) ◽  
pp. 121-130 ◽  
Author(s):  
Reshma Kulkarni ◽  
Gajanan N. Sapkal ◽  
Himanshu Kaushal ◽  
Devendra T. Mourya

Introduction: Japanese encephalitis (JE) is recently declared as a notifiable disease in India due to its expanding geographical distribution. The disease notification facilitates effective implementation of preventive measures and case management. Expalantion: JE is a vector-borne disease that can be prevented by vaccine administration. It is caused by Japanese encephalitis virus (JEV), belonging to family Flaviviridae. Amongst the known etiological viral encephalitis agents, it is one of the leading viral agents of acute encephalitis syndrome in many Asian countries where it is identified to cause substantial morbidity and mortality as well as disability. Globally, it is responsible for approximately 68,000 clinical cases every year. Conclusion: In the absence of antivirals, patients are given supportive treatment to relieve and stabilize. Amongst available control strategies; vector control is resource intensive while animal and human vaccination are the most effective tool against the disease. This review highlights recent progress focusing challenges with diagnosis and prophylactic interventions.


2018 ◽  
Vol 12 (2) ◽  
pp. 21-23
Author(s):  
Arifa Akram

Viral encephalitis remains a significant public health problem worldwide and one of the most important causes of mosquito borne viral encephalitis not only in Asia but all over the world. Its transmission is either from insect or environmental vectors or from human-to-human contact. It causes severe disease in humans, resulting in death or permanent neurologic deficits among the person who survives. As the risk of Japanese Encephalitis is persisting, implementation of strategies that will strengthen Japanese Encephalitis surveillance systems to understand the disease burden and apply vaccination protocols in national childhood immunization programs in Bangladesh. Bangladesh J Med Microbiol 2018; 12 (2): 21-23


F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 6
Author(s):  
Pyae Phyo Kyaw ◽  
Hemant Deepak Shewade ◽  
Nang Thu Thu Kyaw ◽  
Khaing Hnin Phyo ◽  
Htar Htar Lin ◽  
...  

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.


2019 ◽  
Vol 94 (5) ◽  
Author(s):  
Fatima Amanat ◽  
James Duehr ◽  
Cheng Huang ◽  
Slobodan Paessler ◽  
Gene S. Tan ◽  
...  

ABSTRACT Machupo virus (MACV), the causative agent of Bolivian hemorrhagic fever (BHF), is a New World arenavirus that was first isolated in Bolivia from a human spleen in 1963. Due to the lack of a specific vaccine or therapy, this virus is considered a major risk to public health and is classified as a category A priority pathogen by the U.S. National Institutes of Health. In this study, we used DNA vaccination against the MACV glycoprotein precursor complex (GPC) and murine hybridoma technology to generate 25 mouse monoclonal antibodies (MAbs) against the GPC of MACV. Out of 25 MAbs, five were found to have potent neutralization activity in vitro against a recombinant vesicular stomatitis virus expressing MACV GPC (VSV-MACV) as well as against authentic MACV. Furthermore, the five neutralizing MAbs exhibited strong antibody-dependent cellular cytotoxicity (ADCC) activity in a reporter assay. When tested in vivo using VSV-MACV in a Stat2−/− mouse model, three MAbs significantly lowered viral loads in the spleen. Our work provides valuable insights into epitopes targeted by neutralizing antibodies that could be potent targets for vaccines and therapeutics and shed light on the importance of effector functions in immunity against MACV. IMPORTANCE MACV infections are a significant public health concern and lead to high case fatality rates. No specific treatment or vaccine for MACV infections exist. However, cases of Junin virus infection, a related virus, can be treated with convalescent-phase serum. This indicates that a MAb-based therapy for MACV could be effective. Here, we describe several MAbs that neutralize MACV and could be used for this purpose.


2005 ◽  
Vol 44 (158) ◽  
Author(s):  
Mahendra Bahadur Bista ◽  
J M Shrestha

A human Japanese encephalitis (JE) case is considered to have elevated temperature (over 380C) along withaltered consciousness or unconsciousness and is generally confirmed serologically by finding of specific anti-JEIgM in the cerebro spinal fluid. No specific treatment for JE is available. Only supportive treatment likemeticulous nursing care, introduction of Ryle’s tube if the patient is unconscious, dextrose solution if dehydrationis present, manitol injection in case of raised cranial temperature and diazepam in case of convulsion. Intravenous fluids, indwelling catheter in conscious patient and corticosteroids unless indicated should be avoided.Pigs, wading birds and ducks have been incriminated as important vertebrate amplifying hosts for JE virusdue to viremia in them. Man along with bovines, ovines and caprines is involved in transmission cycle asaccidental hosts and plays no role in perpetuating the virus due to the lack of viremia in them. The species Cxtritaeniorhyncus is suspected to be the principal vector of JE in Nepal as the species is abundantly found in therice-field ecosystemof the endemic areas during the transmission season and JE virus isolates have been obtainedfrom a pool of Cx tritaeniorhyncus females. Mosquito vector become infective 14 days after acquiring the JRvirus from the viremic host. The disease was first recorded in Nepal in 1978 as an epidemic in Rupandehidistrict of the Western Development Region (WDR) and Morang of the Eastern Region (EDR). At present thedisease is endemic in 24 districts.Although JE as found endemic mainly in tropical climate areas, existense andproliferation of encephalitis causing viruses in temperate and cold climates of hills and valleys are possible.Total of 26,667 cases and 5,381 deaths have been reported with average case fatality rate of 20.2% in anaggregate since 1978. More than 50% of morbidity and 60% mortality occur in the age group below 15 years.Upsurge of cases take place after the rainy season (monsoon). Cases start to appear in the month ofApril - Mayand reach its peak during late August to early September and start to decline from October. There are fourdesignated referral laboratories, namely National Public Health Laboratory (Teku), Vector Borne DiseasesResearch and Training Center (Hetauda), B.P. Koirala Institute of Medical Sciences (Dharan) and JE Laboratory(Nepalgunj), for confirmatory diagnosis of JE. For prevention of JE infection;chemical and biological controlof vectors including environmental management at breeding sites are necessary. Segregate pigs from humanshabitation. Wear long sleeved clothes and trousersand use repellent and bed net to avoid exposure to mosquitos.For the prevention of the disease in humans, safe and efficacious vaccines are available. Therefore immunizepopulation at risk against JE. Immunize pigs at the surroundings against JE. 225,000 doses of live attenuatedSA-14-14.2 JE vaccine were received in donation from Boran Pharmaceuticals, South Korea for the first timein Nepal. Altogether 224,000 children aged between 1 to 15 years were vaccinated in Banke, Bardiya andKailali districts during 1999. From China also, 2,000,000 doses of inactivated vaccine were received in 2000and a total of 481,421 children aged between 6m to 10 yrswere protected from JE during 2001/2002. Ministryof Agriculture, Department of Livestock Services has vaccinated around 200,000 pigs against JE in terai zoneduring February 2001.Key Words: Supportive treatment, viremia, amplifying host, vectors, vaccination/immunization.


F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 6
Author(s):  
Pyae Phyo Kyaw ◽  
Hemant Deepak Shewade ◽  
Nang Thu Thu Kyaw ◽  
Khaing Hnin Phyo ◽  
Htar Htar Lin ◽  
...  

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.


2018 ◽  
Vol 10 (468) ◽  
pp. eaat6420 ◽  
Author(s):  
Jose L. Garrido ◽  
Joseph Prescott ◽  
Mario Calvo ◽  
Felipe Bravo ◽  
Raymond Alvarez ◽  
...  

Andes hantavirus (ANDV) is an etiologic agent of hantavirus cardiopulmonary syndrome (HCPS), a severe disease characterized by fever, headache, and gastrointestinal symptoms that may progress to hypotension, pulmonary failure, and cardiac shock that results in a 25 to 40% case-fatality rate. Currently, there is no specific treatment or vaccine; however, several studies have shown that the generation of neutralizing antibody (Ab) responses strongly correlates with survival from HCPS in humans. In this study, we screened 27 ANDV convalescent HCPS patient sera for their capacity to bind and neutralize ANDV in vitro. One patient who showed high neutralizing titer was selected to isolate ANDV–glycoprotein (GP) Abs. ANDV-GP–specific memory B cells were single cell sorted, and recombinant immunoglobulin G antibodies were cloned and produced. Two monoclonal Abs (mAbs), JL16 and MIB22, potently recognized ANDV-GPs and neutralized ANDV. We examined the post-exposure efficacy of these two mAbs as a monotherapy or in combination therapy in a Syrian hamster model of ANDV-induced HCPS, and both mAbs protected 100% of animals from a lethal challenge dose. These data suggest that monotherapy with mAb JL16 or MIB22, or a cocktail of both, could be an effective post-exposure treatment for patients infected with ANDV-induced HCPS.


2021 ◽  
Vol 20 (1) ◽  
pp. 13-24
Author(s):  
Sajana Thapa ◽  
◽  
Anucha Sirimalaisuwan ◽  
Kannika Na Lampang ◽  
Veerasak Panyapornwittaya ◽  
...  

Japanese encephalitis is a serious vector borne viral zoonotic disease, particularly in Asia and Northern Australia. In Nepal, JE cases were reported in 63 out of 75 districts up until the year 2005. The aim of this study was to assess the level of knowledge, attitude and practices (KAP) toward JE and associated factors. A structured questionnaire was used to gather information on the KAP of people in endemic areas. Accordingly, 397 respondents demonstrated a desirable attitude, while half of the population exhibited desirable knowledge and practices. Age was found to be a significant factor for knowledge, wherein the senior population had better awareness of the vectors of JE. Moreover, education and occupation were found to be significant factors for KAP scores with an increase in level of education leading to an increase in desirable characteristics. This study determined that the characteristics of the surrounding environment were prominent factors. A significant number of people were not aware of the JE vaccine even though the government has made it available to most of the population of Nepal. Thus, more effective awareness programs should be implemented to increase the KAP of the population with regard to JE.


2007 ◽  
Vol 82 (3) ◽  
pp. 1332-1338 ◽  
Author(s):  
Jay W. Hooper ◽  
Anthony M. Ferro ◽  
Victoria Wahl-Jensen

ABSTRACT Hantavirus pulmonary syndrome (HPS) is a highly pathogenic disease (40% case fatality rate) carried by rodents chronically infected with certain viruses within the genus Hantavirus of the family Bunyaviridae. The primary mode of transmission to humans is thought to be inhalation of excreta from infected rodents; however, ingestion of contaminated material and rodent bites are also possible modes of transmission. Person-to-person transmission of HPS caused by one species of hantavirus, Andes virus (ANDV), has been reported. Previously, we reported that ANDV injected intramuscularly causes a disease in Syrian hamsters that closely resembles HPS in humans. Here we tested whether ANDV was lethal in hamsters when it was administered by routes that more accurately model the most common routes of human infection, i.e., the subcutaneous, intranasal, and intragastric routes. We discovered that ANDV was lethal by all three routes. Remarkably, even at very low doses, ANDV was highly pathogenic when it was introduced by the mucosal routes (50% lethal dose [LD50], ∼100 PFU). We performed passive transfer experiments to test the capacity of neutralizing antibodies to protect against lethal intranasal challenge. The neutralizing antibodies used in these experiments were produced in rabbits vaccinated by electroporation with a previously described ANDV M gene-based DNA vaccine, pWRG/AND-M. Hamsters that were administered immune serum on days −1 and +5 relative to challenge were protected against intranasal challenge (21 LD50). These findings demonstrate the utility of using the ANDV hamster model to study transmission across mucosal barriers and provide evidence that neutralizing antibodies produced by DNA vaccine technology can be used to protect against challenge by the respiratory route.


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