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Clinics in Laboratory Medicine Mar 2010West Nile virus (WNV) is responsible for thousands of cases of morbidity and mortality in birds, horses, and humans. Epidemics were localized to Europe, Africa, the... (Review)
Review
West Nile virus (WNV) is responsible for thousands of cases of morbidity and mortality in birds, horses, and humans. Epidemics were localized to Europe, Africa, the Middle East, and parts of Asia, and primarily caused a mild febrile illness in humans. In the late 1990s, the virus became more virulent and spread to North America. In humans, the clinical presentation ranges from asymptomatic, seen frequently, to encephalitis/paralysis and death, seen rarely. There is no FDA (Food and Drug Administration)-licensed vaccine for human use, and the only recommended treatment is supportive care. Often, there is a long recovery period. This article reviews the current literature summarizing the molecular virology, epidemiology, clinical manifestations, pathogenesis, diagnosis, treatment, immunology, and protective measures against WNV and WNV infections in humans.
Topics: Diagnosis, Differential; Humans; Phylogeny; Vaccination; West Nile Fever; West Nile virus
PubMed: 20513541
DOI: 10.1016/j.cll.2009.10.006 -
The Lancet. Infectious Diseases Sep 2002West Nile (WN) virus is a mosquito-borne flavivirus and human, equine, and avian neuropathogen. The virus is indigenous to Africa, Asia, Europe, and Australia, and has... (Review)
Review
West Nile (WN) virus is a mosquito-borne flavivirus and human, equine, and avian neuropathogen. The virus is indigenous to Africa, Asia, Europe, and Australia, and has recently caused large epidemics in Romania, Russia, and Israel. Birds are the natural reservoir (amplifying) hosts, and WN virus is maintained in nature in a mosquito-bird-mosquito transmission cycle primarily involving Culex sp mosquitoes. WN virus was recently introduced to North America, where it was first detected in 1999 during an epidemic of meningoencephalitis in New York City. During 1999-2002, the virus extended its range throughout much of the eastern parts of the USA, and its range within the western hemisphere is expected to continue to expand. During 1999-2001, 142 cases of neuroinvasive WN viral disease of the central nervous system (including 18 fatalities), and seven cases of uncomplicated WN fever were reported in the USA. Most human WN viral infections are subclinical but clinical infections can range in severity from uncomplicated WN fever to fatal meningoencephalitis; the incidence of severe neuroinvasive disease and death increase with age. Serology remains the mainstay of laboratory diagnosis. No WN virus-specific treatment or vaccine is available. Prevention depends on organised, sustained vector mosquito control, and public education.
Topics: Adolescent; Adult; Age Distribution; Aged; Aged, 80 and over; Animals; Child; Child, Preschool; Disease Reservoirs; Female; Humans; Infant; Male; Middle Aged; Mosquito Control; Sex Distribution; West Nile Fever; West Nile virus
PubMed: 12206968
DOI: 10.1016/s1473-3099(02)00368-7 -
PLoS Pathogens Oct 2019It has been 20 years since West Nile virus first emerged in the Americas, and since then, little progress has been made to control outbreaks caused by this virus. After... (Review)
Review
It has been 20 years since West Nile virus first emerged in the Americas, and since then, little progress has been made to control outbreaks caused by this virus. After its first detection in New York in 1999, West Nile virus quickly spread across the continent, causing an epidemic of human disease and massive bird die-offs. Now the virus has become endemic to the United States, where an estimated 7 million human infections have occurred, making it the leading mosquito-borne virus infection and the most common cause of viral encephalitis in the country. To bring new attention to one of the most important mosquito-borne viruses in the Americas, we provide an interactive review using Nextstrain: a visualization tool for real-time tracking of pathogen evolution (nextstrain.org/WNV/NA). Nextstrain utilizes a growing database of more than 2,000 West Nile virus genomes and harnesses the power of phylogenetics for students, educators, public health workers, and researchers to visualize key aspects of virus spread and evolution. Using Nextstrain, we use virus genomics to investigate the emergence of West Nile virus in the U S, followed by its rapid spread, evolution in a new environment, establishment of endemic transmission, and subsequent international spread. For each figure, we include a link to Nextstrain to allow the readers to directly interact with and explore the underlying data in new ways. We also provide a brief online narrative that parallels this review to further explain the data and highlight key epidemiological and evolutionary features (nextstrain.org/narratives/twenty-years-of-WNV). Mirroring the dynamic nature of outbreaks, the Nextstrain links provided within this paper are constantly updated as new West Nile virus genomes are shared publicly, helping to stay current with the research. Overall, our review showcases how genomics can track West Nile virus spread and evolution, as well as potentially uncover novel targeted control measures to help alleviate its public health burden.
Topics: Computational Biology; Databases, Genetic; Disease Transmission, Infectious; Evolution, Molecular; Genome, Viral; Humans; United States; West Nile Fever; West Nile virus
PubMed: 31671157
DOI: 10.1371/journal.ppat.1008042 -
Current Drug Targets. Infectious... May 2001Within the past 5 years, West Nile encephalitis has emerged as an important disease of humans and horses in Europe. In 1999, the disease appeared for the first time in... (Review)
Review
Within the past 5 years, West Nile encephalitis has emerged as an important disease of humans and horses in Europe. In 1999, the disease appeared for the first time in the northeastern United States. West Nile virus (a mosquito-borne flavivirus) has flourished in the North American ecosystem and is expected to expand its geographic range. In this review, the rationale for a human and veterinary vaccine is presented and a novel approach for rapid development of a molecularly-defined, live, attenuated vaccine is described. The technology (ChimeriVax) is applicable to the development of vaccines against all flaviviruses, and products against Japanese encephalitis (a close relative of West Nile) and dengue are in or are nearing clinical trials, respectively. ChimeriVax vaccines utilize the safe and effective vaccine against the prototype flavivirus -yellow fever 17D- as a live vector. Infectious clone technology is used to replace the genes encoding the pre-membrane (prM) and envelope (E) protein of yellow fever 17D vaccine with the corresponding genes of the target virus (e.g., West Nile). The resulting chimeric virus contains the antigens responsible for protection against West Nile but retains the replication efficiency of yellow fever 17D. The ChimeriVax technology is well-suited to the rapid development of a West Nile vaccine, and clinical trials could begin as early as mid-2002. Other approaches to vaccine development are briefly reviewed. The aim of this brief review is to describe the features of West Nile encephalitis, a newly introduced infectious disease affecting humans, horses and wildlife in the United States; the rationale for rapid development of vaccines; and approaches to the development of vaccines against the disease.
Topics: Animals; Clinical Trials as Topic; Culicidae; Genome, Viral; Humans; Macaca mulatta; Mice; Viral Vaccines; Viremia; Virulence; West Nile Fever; West Nile virus
PubMed: 12455232
DOI: 10.2174/1568005013343254 -
Integrative Zoology Sep 2011West Nile virus, a mosquito-vectored flavivirus of the Japanese encephalitis serogroup, was first detected in North America following an epizootic in the New York City... (Review)
Review
West Nile virus, a mosquito-vectored flavivirus of the Japanese encephalitis serogroup, was first detected in North America following an epizootic in the New York City area in 1999. In the intervening 11 years since the arrival of the virus in North America, it has crossed the contiguous USA, entered the Canadian provinces bordering the USA, and has been reported in the Caribbean islands, Mexico, Central America and, more recently, South America. West Nile virus has been reported in over 300 species of birds in the USA and has caused the deaths of thousands of birds, local population declines of some avian species, the clinical illness and deaths of thousands of domestic horses, and the clinical disease in over 30 000 Americans and the deaths of over 1000. Prior to the emergence of West Nile virus in North America, St. Louis encephalitis virus and Dengue virus were the only other known mosquito-transmitted flaviviruses in North America capable of causing human disease. This review will discuss the North American experience with mosquito-borne flavivirus prior to the arrival of West Nile virus, the entry and spread of West Nile virus in North America, effects on wild bird populations, genetic changes in the virus, and the current state of West Nile virus transmission.
Topics: Animals; Bird Diseases; Birds; North America; Population Dynamics; West Nile Fever; West Nile virus
PubMed: 21910847
DOI: 10.1111/j.1749-4877.2011.00251.x -
Bundesgesundheitsblatt,... Aug 2012
Review
Topics: Animals; Antibodies, Viral; Blood-Borne Pathogens; Communicable Diseases, Emerging; Cross-Sectional Studies; Disease Models, Animal; Disease Reservoirs; Disease Vectors; Europe; Germany; Humans; Microscopy, Electron; National Health Programs; Population Surveillance; Public Health; Virion; Virulence; West Nile Fever; West Nile virus
PubMed: 22842895
DOI: 10.1007/s00103-012-1507-2 -
Viruses Jun 2011West Nile virus (WNV) is a neurotropic, arthropod-borne flavivirus that is maintained in an enzootic cycle between mosquitoes and birds, but can also infect and cause... (Review)
Review
West Nile virus (WNV) is a neurotropic, arthropod-borne flavivirus that is maintained in an enzootic cycle between mosquitoes and birds, but can also infect and cause disease in horses and humans. WNV is endemic in parts of Africa, Europe, the Middle East, and Asia, and since 1999 has spread to North America, Mexico, South America, and the Caribbean. WNV infects the central nervous system (CNS) and can cause severe disease in a small minority of infected humans, mostly immunocompromised or the elderly. This review discusses some of the mechanisms by which the immune system can limit dissemination of WNV infection and elaborates on the mechanisms involved in pathogenesis. Reasons for susceptibility to WNV-associated neuroinvasive disease in less than 1% of cases remain unexplained, but one favored hypothesis is that the involvement of the CNS is associated with a weak immune response allowing robust WNV replication in the periphery and spread of the virus to the CNS.
Topics: Animals; Central Nervous System; Humans; Immunity; West Nile Fever; West Nile virus
PubMed: 21994755
DOI: 10.3390/v3060811 -
Current Opinion in Virology Dec 2016West Nile virus remains the most common cause of arboviral encephalitis in North America. Since it was introduced, it has undergone adaptive genetic change as it spread... (Review)
Review
West Nile virus remains the most common cause of arboviral encephalitis in North America. Since it was introduced, it has undergone adaptive genetic change as it spread throughout the continent. The WNV transmission cycle is relatively tractable in the laboratory. Thus the virus serves as a convenient model system for studying the population biology of mosquito-borne flaviviruses as they undergo transmission to and from mosquitoes and vertebrates. This review summarizes the current knowledge regarding the population dynamics of this virus within mosquito vectors.
Topics: Adaptation, Biological; Animals; Mosquito Vectors; North America; Population Dynamics; West Nile virus
PubMed: 27788400
DOI: 10.1016/j.coviro.2016.09.007 -
Infection, Genetics and Evolution :... Mar 2012West Nile virus (WNV) (Flaviviridae: Flavivirus) is transmitted from mosquitoes to birds, but can cause fatal encephalitis in infected humans. Since its introduction... (Review)
Review
West Nile virus (WNV) (Flaviviridae: Flavivirus) is transmitted from mosquitoes to birds, but can cause fatal encephalitis in infected humans. Since its introduction into North America in New York in 1999, it has spread throughout the western hemisphere. Multiple outbreaks have also occurred in Europe over the last 20 years. This review highlights recent efforts to understand how host pressures impact viral population genetics, genotypic and phenotypic changes which have occurred in the WNV genome as it adapts to this novel environment, and molecular epidemiology of WNV worldwide. Future research directions are also discussed.
Topics: Animals; Biological Evolution; Genetic Fitness; Host-Pathogen Interactions; Humans; Population Dynamics; West Nile Fever; West Nile virus
PubMed: 22226703
DOI: 10.1016/j.meegid.2011.11.014 -
Veterinary Research Mar 2012West Nile virus (WNV) is a positive-stranded RNA virus belonging to the Flaviviridae family, a large family with 3 main genera (flavivirus, hepacivirus and pestivirus).... (Review)
Review
West Nile virus (WNV) is a positive-stranded RNA virus belonging to the Flaviviridae family, a large family with 3 main genera (flavivirus, hepacivirus and pestivirus). Among these viruses, there are several globally relevant human pathogens including the mosquito-borne dengue virus (DENV), yellow fever virus (YFV), Japanese encephalitis virus (JEV) and West Nile virus (WNV), as well as tick-borne viruses such as tick-borne encephalitis virus (TBEV). Since the mid-1990s, outbreaks of WN fever and encephalitis have occurred throughout the world and WNV is now endemic in Africa, Asia, Australia, the Middle East, Europe and the Unites States. This review describes the molecular virology, epidemiology, pathogenesis, and highlights recent progress regarding diagnosis and vaccination against WNV infections.
Topics: Animals; Birds; Humans; Mammals; Vaccination; Viral Vaccines; West Nile Fever; West Nile virus
PubMed: 22380523
DOI: 10.1186/1297-9716-43-16