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Journal of Medical Entomology Oct 2019Over the past 20 yr, many models have been developed to predict risk for West Nile virus (WNV; Flaviviridae: Flavivirus) disease in the human population. These models... (Review)
Review
Over the past 20 yr, many models have been developed to predict risk for West Nile virus (WNV; Flaviviridae: Flavivirus) disease in the human population. These models have aided our understanding of the meteorological and land-use variables that drive spatial and temporal patterns of human disease risk. During the same period, electronic data systems have been adopted by surveillance programs across much of the United States, including a growing interest in integrated data services that preserve the autonomy and attribution of credit to originating agencies but facilitate data sharing, analysis, and visualization at local, state, and national scales. At present, nearly all predictive models have been limited to the scientific literature, with few having been implemented for use by public-health and vector-control decision makers. The current article considers the development of models for spatial patterns, early warning, and early detection of WNV over the last 20 yr and considers some possible paths toward increasing the utility of these models for guiding interventions.
Topics: Disease Outbreaks; Epidemiological Monitoring; Humans; Models, Theoretical; Public Health; Seasons; United States; West Nile Fever; West Nile virus
PubMed: 31549727
DOI: 10.1093/jme/tjz150 -
Journal of Medical Entomology Oct 2019Over 50,000 human West Nile virus (WNV) (Flaviviridae: Flavivirus) clinical disease cases have been reported to the CDC during the 20 yr that the virus has been present... (Review)
Review
Over 50,000 human West Nile virus (WNV) (Flaviviridae: Flavivirus) clinical disease cases have been reported to the CDC during the 20 yr that the virus has been present in the United States. Despite the establishment and expansion of WNV-focused mosquito surveillance and control efforts and a renewed emphasis on applying integrated pest management (IPM) principles to WNV control, periodic local and regional WNV epidemics with case reports exceeding 2,000 cases per year have occurred during 13 of those 20 yr in the United States. In this article, we examine the scientific literature for evidence that mosquito control activities directed at either preventing WNV outbreaks or stopping those outbreaks once in progress reduce WNV human disease or have a measurable impact on entomological indicators of human WNV risk. We found that, despite a proliferation of research investigating larval and adult mosquito control effectiveness, few of these studies actually measure epidemiological outcomes or the entomological surrogates of WNV risk. Although many IPM principles (e.g., control decisions based on surveillance, use of multiple control methodologies appropriate for the ecosystem) have been implemented effectively, the use of action thresholds or meaningful public health outcome assessments have not been used routinely. Establishing thresholds for entomological indicators of human risk analogous to the economic injury level and economic thresholds utilized in crop IPM programs may result in more effective WNV prevention.
Topics: Animals; Culex; Humans; Incidence; Mosquito Control; Mosquito Vectors; Risk; United States; West Nile Fever; West Nile virus
PubMed: 31549724
DOI: 10.1093/jme/tjz083 -
Frontiers in Immunology 2022Obesity is a global health problem that affects 650 million people worldwide and leads to diverse changes in host immunity. Individuals with obesity experience an... (Review)
Review
Obesity is a global health problem that affects 650 million people worldwide and leads to diverse changes in host immunity. Individuals with obesity experience an increase in the size and the number of adipocytes, which function as an endocrine organ and release various adipocytokines such as leptin and adiponectin that exert wide ranging effects on other cells. In individuals with obesity, macrophages account for up to 40% of adipose tissue (AT) cells, three times more than in adipose tissue (10%) of healthy weight individuals and secrete several cytokines and chemokines such as interleukin (IL)-1β, chemokine C-C ligand (CCL)-2, IL-6, CCL5, and tumor necrosis factor (TNF)-α, leading to the development of inflammation. Overall, obesity-derived cytokines strongly affect immune responses and make patients with obesity more prone to severe symptoms than patients with a healthy weight. Several epidemiological studies reported a strong association between obesity and severe arthropod-borne virus (arbovirus) infections such as dengue virus (DENV), chikungunya virus (CHIKV), West Nile virus (WNV), and Sindbis virus (SINV). Recently, experimental investigations found that DENV, WNV, CHIKV and Mayaro virus (MAYV) infections cause worsened disease outcomes in infected diet induced obese (DIO) mice groups compared to infected healthy-weight animals. The mechanisms leading to higher susceptibility to severe infections in individuals with obesity remain unknown, though a better understanding of the causes will help scientists and clinicians develop host directed therapies to treat severe disease. In this review article, we summarize the effects of obesity on the host immune response in the context of arboviral infections. We have outlined that obesity makes the host more susceptible to infectious agents, likely by disrupting the functions of innate and adaptive immune cells. We have also discussed the immune response of DIO mouse models against some important arboviruses such as CHIKV, MAYV, DENV, and WNV. We can speculate that obesity-induced disruption of innate and adaptive immune cell function in arboviral infections ultimately affects the course of arboviral disease. Therefore, further studies are needed to explore the cellular and molecular aspects of immunity that are compromised in obesity during arboviral infections or vaccination, which will be helpful in developing specific therapeutic/prophylactic interventions to prevent immunopathology and disease progression in individuals with obesity.
Topics: Animals; Mice; Arbovirus Infections; Obesity; Mice, Obese; Chikungunya virus; West Nile virus; Immunity
PubMed: 36466818
DOI: 10.3389/fimmu.2022.968582 -
Expert Review of Anti-infective Therapy Feb 2020: West Nile virus (WNV) is a mosquito-borne human and animal pathogen with nearly worldwide distribution. In Europe, the virus is endemic with seasonal regional... (Review)
Review
: West Nile virus (WNV) is a mosquito-borne human and animal pathogen with nearly worldwide distribution. In Europe, the virus is endemic with seasonal regional outbreaks that have increased in frequency over the last 10 years. A massive outbreak occurred across southern and central Europe in 2018 with the number of confirmed human cases increasing up to 7.2-fold from the previous year, and expanding to include previously virus-free regions.: This review focuses on potential causes that may explain the 2018 European WNV outbreak. We discuss the role genetic, ecological, and environmental aspects may have played in the increased activity during the 2018 transmission season, summarizing the latest epidemiological and virological publications.: Optimal environmental conditions, specifically increased temperature, were most likely responsible for the observed outbreak. Other factors cannot be ruled out due to limited available information, including factors that may influence host/vector abundance and contact. Europe will likely experience even larger-scale outbreaks in the coming years. Increased surveillance efforts should be implemented with a focus on early-warning detection methods, and large-scale host and vector surveys should continue to fill gaps in knowledge.
Topics: Animals; Disease Outbreaks; Europe; Humans; Mosquito Vectors; Seasons; Temperature; West Nile Fever; West Nile virus
PubMed: 31914833
DOI: 10.1080/14787210.2020.1713751 -
Virologie (Montrouge, France) Oct 2019
Topics: Europe; Humans; West Nile Fever; West Nile virus
PubMed: 31826847
DOI: 10.1684/vir.2019.0787 -
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 -
Virologica Sinica Feb 2021West Nile virus (WNV) is an important neurotropic flavivirus that is widely distributed globally. WNV strain XJ11129 was first isolated in Xinjiang, China, and its...
West Nile virus (WNV) is an important neurotropic flavivirus that is widely distributed globally. WNV strain XJ11129 was first isolated in Xinjiang, China, and its genetic and biological characteristics remain largely unknown. In this study, phylogenetic and sequence analyses revealed that XJ11129 belongs to lineage 1a and shares high genetic identity with the highly pathogenic strain NY99. Then, the full-length genomic cDNA of XJ11129 was amplified and assembled using a modified Gibson assembly (GA) method. The virus (named rXJ11129) was successfully rescued in days following this method. Compared with other wild-type WNV isolates, rXJ11129 exhibited virulence indistinguishable from that of the NY99 strain in vivo. In summary, the genomic and virulence phenotypes of rXJ11129 were characterized in vivo and in vitro, and these data will improve the understanding of the spread and pathogenesis of this reemerging virus.
Topics: China; Flavivirus; Humans; Phylogeny; West Nile Fever; West Nile virus
PubMed: 32632819
DOI: 10.1007/s12250-020-00246-x -
Journal of Medical Entomology Oct 2019The establishment of a tropical virus such as West Nile (WNV; Flaviviridae: Flavivirus) within the temperate latitudes of the continental United States was unexpected... (Review)
Review
The establishment of a tropical virus such as West Nile (WNV; Flaviviridae: Flavivirus) within the temperate latitudes of the continental United States was unexpected and perhaps contingent, in part, upon the ability of this invasive virus to persist during winter when temperatures become too cold for replication and vector mosquito gonotrophic activity. Our Forum article reviews research examining possible overwintering mechanisms that include consistent reintroduction and local persistence in vector mosquitoes and avian hosts, mostly using examples from research conducted in California. We conclude that the transmission of WNV involves so many vectors and hosts within different landscapes that multiple overwintering pathways are possible and collectively may be necessary to allow this virus to overwinter consistently within the United States.
Topics: Animals; Bird Diseases; Birds; Culex; Host-Pathogen Interactions; Mosquito Vectors; Seasons; Species Specificity; United States; West Nile Fever; West Nile virus
PubMed: 31549726
DOI: 10.1093/jme/tjz070 -
Viruses May 2023West Nile virus (WNV) neuroinvasive disease threatens the health and well-being of horses and humans worldwide. Disease in horses and humans is remarkably similar. The... (Review)
Review
West Nile virus (WNV) neuroinvasive disease threatens the health and well-being of horses and humans worldwide. Disease in horses and humans is remarkably similar. The occurrence of WNV disease in these mammalian hosts has geographic overlap with shared macroscale and microscale drivers of risk. Importantly, intrahost virus dynamics, the evolution of the antibody response, and clinicopathology are similar. The goal of this review is to provide a comparison of WNV infection in humans and horses and to identify similarities that can be exploited to enhance surveillance methods for the early detection of WNV neuroinvasive disease.
Topics: Humans; Horses; Animals; West Nile virus; West Nile Fever; Sentinel Surveillance; Mammals; Horse Diseases
PubMed: 37376530
DOI: 10.3390/v15061230 -
International Journal of Molecular... Nov 2020West Nile virus (WNV), like the dengue virus (DENV) and yellow fever virus (YFV), are major arboviruses belonging to the genus. WNV is emerging or endemic in many... (Review)
Review
West Nile virus (WNV), like the dengue virus (DENV) and yellow fever virus (YFV), are major arboviruses belonging to the genus. WNV is emerging or endemic in many countries around the world, affecting humans and other vertebrates. Since 1999, it has been considered to be a major public and veterinary health problem, causing diverse pathologies, ranging from a mild febrile state to severe neurological damage and death. WNV is transmitted in a bird-mosquito-bird cycle, and can occasionally infect humans and horses, both highly susceptible to the virus but considered dead-end hosts. Many studies have investigated the molecular determinants of WNV virulence, mainly with the ultimate objective of guiding vaccine development. Several vaccines are used in horses in different parts of the world, but there are no licensed WNV vaccines for humans, suggesting the need for greater understanding of the molecular determinants of virulence and antigenicity in different hosts. Owing to technical and economic considerations, WNV virulence factors have essentially been studied in rodent models, and the results cannot always be transported to mosquito vectors or to avian hosts. In this review, the known molecular determinants of WNV virulence, according to invertebrate (mosquitoes) or vertebrate hosts (mammalian and avian), are presented and discussed. This overview will highlight the differences and similarities found between WNV hosts and models, to provide a foundation for the prediction and anticipation of WNV re-emergence and its risk of global spread.
Topics: Animals; Culicidae; Disease Models, Animal; Disease Susceptibility; Host Specificity; Host-Pathogen Interactions; Humans; Invertebrates; Mosquito Vectors; Species Specificity; Vertebrates; Virulence; West Nile Fever; West Nile virus
PubMed: 33266206
DOI: 10.3390/ijms21239117