ABSTRACT
BACKGROUND: West-Nile-Virus (WNV) is a widely distributed flavivirus that is mainly transmitted between birds through different mosquito species (e.âg. Culex, Aedes), but may also be transmitted to mammals including humans. WNV causes a spectrum of disease, ranging from asymptomatic infection to encephalitis in a minority of cases. Risk factors for severe disease are older age, cardiovascular disease and an immunocompromised state. MEDICAL HISTORY AND CLINICAL EXAMINATION: Here we report about a 60-year-old male patient who was referred to the University Hospital of Halle (Saale) with severe fever two years after kidney transplantation due to hypertensive nephropathy. No infection focus could be found and by day 6 in the course of his illness the patient developed neurologic symptoms and viral encephalitis was suspected. TREATMENT AND COURSE: The patient was initially treated with aciclovir. After initial reduction of immunosuppression, coincident graft dysfunction was treated with methylprednisolon. WNV-infection was suspected due to recent emerging human cases in the nearby area of the city of Leipzig. WNV lineage 2 was detected in the patient's urine by RT-PCR and seroconversion with presence of anti WNV IgM and IgG could be demonstrated. Consecutively, aciclovir treatment was stopped. The patient fully recovered and the transplanted kidney regained adequate function. Kidney biopsy did not reveal gross rejection of the transplant. CONCLUSION: This case highlights the need to consider rarer causes of illness like WNV-infection particularly in risk groups for more severe outcomes of infectious disease. WNV may be detected by PCR in the blood and cerebrospinal fluid early in the course of infection but it is also excreted for a prolonged period of time in the urine. Seroconversion to anti WNV IgG and IgM may be shown but serologic cross-reactivity among members of the flaviviridae family must be considered.
Subject(s)
Kidney Transplantation , Transplant Recipients , West Nile Fever/etiology , Germany , Humans , Male , Middle Aged , Phylogeny , Risk Factors , West Nile Fever/diagnosis , West Nile Fever/drug therapy , West Nile virus/classification , West Nile virus/geneticsABSTRACT
West Nile virus neuroinvasive disease (WNVND) manifests with meningitis, encephalitis, and/or acute flaccid paralysis. It represents less than 1% of the clinical syndromes associated with West Nile virus (WNV) infection in immunocompetent patients. Immunosuppressive therapy is associated with increased risk of WNVND and worse prognosis. We present a patient with WNVND during therapy with rituximab, and a review of the literature for previous similar cases with the goal to describe the clinical spectrum of WNVND in patients treated specifically with rituximab. Our review indicates that the most common initial complaints are fever and altered mental status, brain magnetic resonance imaging often shows bilateral thalamic hyperintensities, and cerebrospinal analysis consistently reveals mild lymphocytic pleocytosis with elevated protein, positive WNV polymerase chain reaction, and negative WNV antibodies. Treatment is usually supportive care, with intravenous immunoglobulins (IVIG) plus corticosteroids and WNV-specific IVIG also used. The disease is usually fatal despite intervention. Our patient's presentation was very similar to prior reports, however demonstrated spontaneous improvement with supportive management only. WNVND is a rare and serious infection with poor prognosis when associated with rituximab therapy. Diagnosis is complicated by absent or delayed development of antibodies. The presence of bilateral thalamic involvement is a diagnostic clue for WNVND. There is insufficient evidence to recommend the use of corticosteroids or IVIG.
Subject(s)
Immunocompromised Host , Leukocytosis/immunology , Lymphoma, Follicular/immunology , Rituximab/adverse effects , Tremor/immunology , West Nile Fever/immunology , Adrenal Cortex Hormones/therapeutic use , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Cyclophosphamide/adverse effects , Doxorubicin/adverse effects , Female , Humans , Immunoglobulins, Intravenous/therapeutic use , Leukocytosis/diagnostic imaging , Leukocytosis/etiology , Leukocytosis/virology , Lymphoma, Follicular/diagnosis , Lymphoma, Follicular/drug therapy , Lymphoma, Follicular/pathology , Middle Aged , Prednisone/adverse effects , Thalamus/diagnostic imaging , Thalamus/immunology , Thalamus/virology , Tremor/diagnostic imaging , Tremor/etiology , Tremor/virology , Vincristine/adverse effects , West Nile Fever/diagnostic imaging , West Nile Fever/etiology , West Nile Fever/virology , West Nile virus/immunology , West Nile virus/pathogenicityABSTRACT
BACKGROUND: West Nile Virus (WNV) is a member of the Japanese Encephalitis (JE) serocomplex within the Flaviviridae family. We report four whole blood donors and one plasma donor with WNV nucleic acid test (NAT)-reactive donations between September 2018 and November 2019, following recent Japanese Encephalitis virus (JEV) vaccination. CASE SERIES: Cases 1 and 4 had reactive WNV NAT donations 1 day after receiving the JEV vaccine. Case 2 had a reactive WNV donation 3 days after receiving the JEV vaccine. Case 3 had a reactive WNV NAT donation 3 days after returning from Arizona and 1 day after receiving the JEV vaccine. Case 5 had a reactive WNV donation the same day as receiving the JEV vaccine. STUDY DESIGN AND METHODS: WNV screening used the Roche cobas WNV nucleic acid test (NAT) (Roche Molecular Systems). Reference testing on WNV-reactive donations was carried out by the National Microbiology Laboratory (NML). JEV vaccine dilutions were also analyzed. RESULTS: Supplemental NAT was negative for WNV and JEV for Cases 1, 3, and 5. Case 2 had a weak amplification curve for one of two JEV NAT targets. Case 4 was JEV NAT-positive, WNV NAT-negative. Serologic testing on donation specimens for Cases 2, 4, and 5 did not support recent or remote WNV infection. JEV vaccine dilutions were detected by both cobas and supplemental NAT. CONCLUSIONS: We recommend implementing a temporary blood donor deferral following a JEV vaccination, if screening utilizes a WNV assay with the capability of detecting other members of the JE serocomplex.
Subject(s)
Blood Donors , Encephalitis Virus, Japanese/immunology , Vaccination , West Nile Fever/diagnosis , West Nile virus/isolation & purification , Adult , Aged , Cross Reactions , Female , Humans , Male , Mass Screening/methods , Middle Aged , Nucleic Acid Amplification Techniques , RNA, Viral/analysis , RNA, Viral/isolation & purification , Vaccination/adverse effects , Virus Inactivation , West Nile Fever/blood , West Nile Fever/etiology , West Nile virus/genetics , Young AdultABSTRACT
Background: West Nile virus is an arthropod-borne virus (arbovirus) and emerging cause of significant illness in European and Mediterranean countries. West Nile virus infection can cause severe and potentially fatal neurological illnesses, including encephalitis, meningitis, and acute flaccid paralysis. Additionally, immunosuppression, alcohol abuse, old age, and diabetes mellitus are common factors associated with West Nile neuroinvasive disease. Case Report: In August 2018, a 60-year-old male patient with a history of diffuse large B-cell lymphoma initially presented with symptoms including abdominal pain and distention, nausea, and vomiting. Three days after open abdominal surgery due to adhesive small bowel obstruction, he developed fever, prominent tremors, and rapidly progressing flaccid paralysis. The identification of West Nile virus RNA in the serum sample led to the diagnosis of West Nile neuroinvasive disease. Conclusion: Clinicians should evaluate patients with acute flaccid paralysis for the evidence of West Nile neuroinvasive disease. It is particularly important for healthcare providers to consider West Nile neuroinvasive disease in the differential diagnosis of aseptic meningitis, encephalitis, and acute paralysis cases, especially in endemic areas.
Subject(s)
Lymphoma, Large B-Cell, Diffuse/complications , West Nile Fever/etiology , Antineoplastic Combined Chemotherapy Protocols , Cyclophosphamide , Doxorubicin , Humans , Lymphoma, B-Cell/complications , Lymphoma, B-Cell/physiopathology , Lymphoma, Large B-Cell, Diffuse/physiopathology , Male , Middle Aged , Plasmapheresis/methods , Prednisone , Quadriplegia/etiology , Quadriplegia/physiopathology , Real-Time Polymerase Chain Reaction/methods , Rituximab , Turkey , Vincristine , West Nile Fever/complications , West Nile Fever/physiopathology , West Nile virus/drug effects , West Nile virus/pathogenicitySubject(s)
Diarrhea/etiology , Meningoencephalitis/diagnosis , West Nile Fever/diagnosis , Adult , Brain/diagnostic imaging , Diagnosis, Differential , Female , Herpes Simplex/complications , Herpesvirus 2, Human , Humans , Immunocompromised Host , Lupus Erythematosus, Systemic/complications , Lupus Nephritis/etiology , Magnetic Resonance Imaging , Meningoencephalitis/etiology , West Nile Fever/etiology , West Nile virus/isolation & purificationABSTRACT
These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the epidemiology, diagnosis, prevention, and management of infection due to Arenaviruses and West Nile Virus (WNV) in the pre- and post-transplant period. Arenaviruses and WNV have been identified as causes of both donor-derived and post-transplant infection. Most data related to these infections have been published in case reports and case series. Transplant recipients may become infected with Arenaviruses if they, or their donors, are exposed to wild rodents or infected pet rodents. Lymphocytic choriomeningitis virus is the most commonly recognized Arenavirus among transplant recipients and should be considered when transplant recipients present with fever, hepatitis, meningitis/encephalitis, and/or multisystem organ failure. WNV is a mosquito-borne virus, and as such, its incidence varies yearly depending on environmental conditions. WNV in transplant recipients typically presents with fever, myalgias, and rash; approximately one in 40 develop neuroinvasive disease. Due to its morbidity, the Organ Procurement and Transplantation Network recently mandated that transplant centers screen living donors for WNV infection in endemic areas. Little is known about the optimal treatment of Arenaviruses or WNV; reduction in immunosuppression and supportive care are the mainstays of management at present.
Subject(s)
Antiviral Agents/therapeutic use , Organ Transplantation/adverse effects , Practice Guidelines as Topic/standards , West Nile Fever/diagnosis , West Nile Fever/drug therapy , West Nile virus/isolation & purification , Humans , Societies, Medical , Transplant Recipients , West Nile Fever/etiologyABSTRACT
Background: This is the first countrywide study of the seroprevalence, risk factors and spatial distribution of West Nile virus (WNV) in Jordan. Methods: A cross-sectional sample of 801 participants was administered a comprehensive questionnaire survey and tested for WNV immunoglobulin G antibodies. Results: The point seroprevalence rate for WNV infection was 8.61% (95% confidence interval 6.8 to 10.8). Multivariate regression analysis demonstrated that sex, age, climate, income and drinking water source were significantly associated with seropositivity (p≤0.05). Males had 1.73 greater odds of infection compared with females. Compared with 15 to 29-year-olds, adults 30-49 y old and adults ≥50 y old had 2.0 and 3.1 greater odds of infection, respectively. Individuals living in the Jordan Valley and Badia had 22.2 and 7.2 times greater odds of infection, respectively, compared with individuals living in the highlands. Households with an income of Subject(s)
West Nile Fever/epidemiology
, West Nile Fever/etiology
, West Nile virus/growth & development
, Adolescent
, Adult
, Aged
, Aged, 80 and over
, Antibodies, Viral/blood
, Child
, Climate
, Cross-Sectional Studies
, Drinking Water
, Female
, Humans
, Immunoglobulin G/blood
, Jordan/epidemiology
, Male
, Middle Aged
, Risk Factors
, Seroepidemiologic Studies
, Socioeconomic Factors
, Spatial Analysis
, Surveys and Questionnaires
, West Nile Fever/blood
, West Nile Fever/virology
, Young Adult
ABSTRACT
How is Texas coping with the deadly diseases that come from bugs?
Subject(s)
Chagas Disease , Chikungunya Fever , Dengue , Disease Outbreaks , Disease Vectors , Typhus, Endemic Flea-Borne , West Nile Fever , Zika Virus Infection , Animals , Chagas Disease/epidemiology , Chagas Disease/etiology , Chikungunya Fever/epidemiology , Chikungunya Fever/etiology , Culicidae , Dengue/epidemiology , Dengue/etiology , Humans , Siphonaptera , Texas/epidemiology , Typhus, Endemic Flea-Borne/epidemiology , Typhus, Endemic Flea-Borne/etiology , Vaccines , West Nile Fever/epidemiology , West Nile Fever/etiology , Zika Virus Infection/epidemiology , Zika Virus Infection/etiologyABSTRACT
BACKGROUND: Clinical syndromes associated with West Nile virus (WNV) infection range from fever to neuroinvasive disease. Understanding WNV epidemiology and disease history is important for guiding patient care and healthcare decision-making. The objective of this review was to characterize the existing body of peer-reviewed and surveillance literature on WNV syndromes and summarize epidemiologic and clinical parameters. METHODS: We followed scoping review methodology described by the Joanna Briggs Institute. Terms related to WNV epidemiology, hospitalization, and surveillance were searched in four bibliographic databases (MEDLINE, EMBASE, Scopus, and CINAHL) for literature published from January 1999 to December 2015. RESULTS: In total, 2334 non-duplicated titles and abstracts were screened; 92 primary studies were included in the review. Publications included one randomized controlled trial and 91 observational studies. Sample sizes ranged from under 25 patients (n = 19) to over 400 patients (n = 28). Eight studies were from Canada, seven from Israel, and the remaining (n = 77) from the United States. N = 17 studies were classified as outbreak case investigations following epidemics; n = 37 with results of regional/national surveillance and monitoring programs. Mean patient ages were > 40 years old; three studies (3%) focused on the pediatric population. Patients with encephalitis fared worse than patients with meningitis and fever, considering hospitalization, length of stay, discharge, recovery, and case-fatality. Several studies examined risk factors; however, age was the only risk factor for neuroinvasive disease/death consistently identified. Overall, patients with acute flaccid paralysis or encephalitis fared worse than patients with meningitis and West Nile fever in terms of hospitalization and mortality. Among the included studies, proportion hospitalized, length of stay, proportion discharged home and case-fatality ranged considerably. CONCLUSION: Our review highlights the heterogeneity among reporting clinical WNV syndromes and epidemiologic parameters of WNV-related illness. Presently, there is potential for further synthesis of the risk factors of WNV-illness and mortality; undertaking further analysis through a systematic review and meta-analysis may benefit our understanding of risk factors for emerging mosquito-borne diseases. Future research on the burden of WNV can build on existing evidence summarized in this review, not only to support our understanding of endemic WNV, but also to strengthen research on emerging arboviruses with similar clinical manifestations.
Subject(s)
West Nile Fever/epidemiology , West Nile Fever/etiology , Animals , Canada/epidemiology , Culicidae/virology , Disease Outbreaks , Hospitalization , Humans , Israel/epidemiology , Patient Discharge/statistics & numerical data , Population Surveillance , Risk Factors , United States/epidemiology , West Nile Fever/mortalityABSTRACT
A 57-year-old male working as a security supervisor in an office building was seen for return to work by the on-site occupational health nurse. He was observed to have slow gait as he entered the clinic waiting area, was pale, diaphoretic, and slow in responding to questions. His return to work note stated he was recovering from West Nile Virus (WNV). Implications for return to work are presented.
Subject(s)
West Nile Fever/diagnosis , Humans , Male , Middle Aged , West Nile Fever/etiology , West Nile Fever/therapyABSTRACT
Multiple mosquito-borne parasites cocirculate in nature and potentially interact. To understand the community of parasites cocirculating with West Nile virus (WNV), we screened the bloodmeal content of Culex pipiens L. mosquitoes for three common types of hemoparasites. Blood-fed Cx. pipiens were collected from a WNV-epidemic area in suburban Chicago, IL, from May to September 2005 through 2010. DNA was extracted from dissected abdomens and subject to PCR and direct sequencing to identify the vertebrate host. RNA was extracted from the head or thorax and screened for WNV using quantitative reverse transcriptase PCR. Seventy-nine engorged females with avian host origin were screened using PCR and amplicon sequencing for filarioid nematodes, Haemosporida, and trypanosomatids. Filarioid nematodes were identified in 3.8% of the blooded abdomens, Plasmodium sp. in 8.9%, Haemoproteus in 31.6%, and Trypanosoma sp. in 6.3%. The sequences from these hemoparasite lineages were highly similar to sequences from birds in prior studies in suburban Chicago. Overall, 50.6% of blood-fed Culex pipiens contained hemoparasite DNA in their abdomen, presumably from current or prior bloodmeals. Additionally, we detected hemoparasite DNA in the blooded abdomen of three of 10 Cx. pipiens infected with WNV.
Subject(s)
Culex/parasitology , Filarioidea/isolation & purification , Haemosporida/isolation & purification , Trypanosomatina/isolation & purification , Animals , Columbidae/parasitology , DNA/isolation & purification , DNA, Helminth/isolation & purification , DNA, Protozoan/isolation & purification , Filarioidea/classification , Filarioidea/genetics , Haemosporida/classification , Haemosporida/genetics , Illinois , Molecular Sequence Data , Phylogeny , Sequence Analysis, DNA/veterinary , Songbirds/parasitology , Trypanosomatina/classification , Trypanosomatina/genetics , West Nile Fever/epidemiology , West Nile Fever/etiology , West Nile Fever/veterinaryABSTRACT
OBJECTIVES: To investigate the epidemiology and outcomes of community-acquired meningitis in older adults. DESIGN: Retrospective study. SETTING: Participants adults in Houston, Texas, with community-acquired meningitis hospitalized between January 1, 2005, and January 1, 2010 (N = 619; n = 54, 8.7%, aged ≥65; n = 565 aged <65). METHODS: An adverse clinical outcome was defined as a Glasgow Outcome Scale score of 4 or less. RESULTS: Older adults had higher rates of comorbidities, abnormal neurological and laboratory (serum white blood cell count >12,000/µL, and cerebrospinal fluid protein >100 mg/dL) findings (P < .001), abnormalities on computed tomography and magnetic resonance imaging of the head (P = .002), and adverse clinical outcomes (ACOs) (P < .001). The majority of participants (65.8%) had meningitis of unknown etiology. Bacterial meningitis was an infrequent cause of community-acquired meningitis (7.4%). Of the known causes, bacterial meningitis and West Nile virus were more common in older than younger adults; younger participants more frequently had cryptococcal and viral meningitis. On logistic regression, female sex was predictive of a poor outcome in the older participants (P = .002), whereas abnormal neurological examination (P < .001), fever (P = .01), and a cerebrospinal fluid glucose level less than 45 mg/dL (P = .002) were significant poor prognostic factors in younger participants. CONCLUSION: Most cases of community-acquired meningitis are of unknown origin. Older adults are more likely than younger adults to have bacterial meningitis and West Nile virus infection when a cause can be identified. They also have more neurological abnormalities, laboratory and imaging abnormalities, and adverse clinical outcomes.
Subject(s)
Community-Acquired Infections/diagnosis , Meningitis, Bacterial/diagnosis , Adolescent , Adult , Age Factors , Aged , Aged, 80 and over , Brain/pathology , Community-Acquired Infections/epidemiology , Community-Acquired Infections/etiology , Comorbidity , Cross-Sectional Studies , Female , Glasgow Outcome Scale , Glucose/cerebrospinal fluid , Humans , Magnetic Resonance Imaging , Male , Meningitis, Bacterial/epidemiology , Meningitis, Bacterial/etiology , Meningitis, Cryptococcal/diagnosis , Meningitis, Cryptococcal/epidemiology , Meningitis, Cryptococcal/etiology , Meningitis, Viral/diagnosis , Meningitis, Viral/epidemiology , Meningitis, Viral/etiology , Middle Aged , Neurologic Examination , Prognosis , Retrospective Studies , Sex Factors , Texas , Tomography, X-Ray Computed , West Nile Fever/diagnosis , West Nile Fever/epidemiology , West Nile Fever/etiology , Young AdultABSTRACT
Emerging and re-emerging mosquito-borne viruses continue to pose a significant threat to human health throughout the world. Over the past decade, West Nile virus (WNV), Dengue virus (DENV), and Chikungunya virus (CHIKV), have caused annual epidemics of virus-induced encephalitis, hemorrhagic fever\shock syndromes, and arthritis, respectively. Currently, no specific antiviral therapies or vaccines exist for use in humans to combat or prevent these viral infections. Thus, there is a pressing need to define the virus-host interactions that govern immunity and infection outcome. Recent technological breakthroughs in 'omics' resources and high-throughput based assays are beginning to accelerate antiviral drug discovery and improve on current strategies for vaccine design. In this review, we highlight studies with WNV and discuss how traditional and systems biological approaches are being used to rapidly identify novel host targets for therapeutic intervention and develop a deeper conceptual understanding of the host response to virus infection.
Subject(s)
Systems Biology , West Nile Fever/etiology , West Nile virus/physiology , Animals , Culicidae/virology , Host-Pathogen Interactions , Humans , Systems Biology/methods , West Nile Fever/transmission , West Nile Fever/virologyABSTRACT
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.
Subject(s)
Biological Evolution , West Nile virus/genetics , Animals , Genetic Fitness , Host-Pathogen Interactions , Humans , Population Dynamics , West Nile Fever/epidemiology , West Nile Fever/etiology , West Nile virus/classificationABSTRACT
West Nile virus (WNV) is generally considered to be an urban pathogen in the United States, but studies associating land cover and disease incidence, seroprevalence, or infection rate in humans, birds, domesticated and wild mammals, and mosquitoes report varying and sometimes contradictory results at an array of spatial extents. Human infection can provide insight about basic transmission activity; therefore, we analyzed data on the incidence of WNV disease in humans to obtain a comprehensive picture of how human disease and land cover type are associated across the United States. Human WNV disease incidence in Northeastern regions was positively associated with urban land covers, whereas incidence in the Western United States was positively associated with agricultural land covers. We suggest that these regional associations are explained by the geographic distributions of prominent WNV vectors: Culex pipiens complex (including Cx. pipiens and Cx. quinquefasciatus) in the Northeast and Cx. tarsalis in the Western United States.
Subject(s)
Geography , West Nile Fever/epidemiology , Agriculture , Environment , Humans , Incidence , United States/epidemiology , Urban Population/statistics & numerical data , West Nile Fever/etiologySubject(s)
Kidney Transplantation , West Nile Fever/diagnosis , West Nile Fever/therapy , Advance Care Planning , Diagnosis, Differential , Ethics Consultation , Fatal Outcome , Female , Humans , Kidney Failure, Chronic/complications , Kidney Failure, Chronic/surgery , Louisiana/epidemiology , Middle Aged , West Nile Fever/epidemiology , West Nile Fever/etiology , Withholding Treatment/legislation & jurisprudenceABSTRACT
West Nile virus (WNV), a single-stranded RNA flavivirus, has spread across the United States since arriving in 1999. While asymptomatic or self-limited in a majority of patients, WNV can cause a severe neuroinvasive disease, which occurs more often in transplant recipients with chronic immunosuppression. Diagnosis of acute WNV infection usually relies on serologic identification of immunoglobulin M (IgM) specific for the virus. We report a fatal case of naturally acquired WNV encephalitis in a renal and pancreas transplant recipient who was seronegative for WNV-specific IgM but had detectable WNV RNA by nucleic acid amplification testing (NAAT) several weeks after the onset of symptoms. This case demonstrates the importance of using both serologic assays and NAAT for WNV in transplant recipients with the clinical suspicion of encephalitis.
Subject(s)
Kidney Transplantation/adverse effects , Pancreas Transplantation/adverse effects , West Nile Fever/etiology , Humans , Male , Middle Aged , Nucleic Acid Amplification Techniques , RNA, Viral/analysis , West Nile Fever/diagnosisABSTRACT
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.
Subject(s)
West Nile Fever/diagnosis , West Nile virus , Diagnosis, Differential , Humans , Phylogeny , Vaccination , West Nile Fever/drug therapy , West Nile Fever/epidemiology , West Nile Fever/etiology , West Nile virus/classification , West Nile virus/genetics , West Nile virus/immunologyABSTRACT
The appearance of West Nile virus in New York in 1999 and the unprecedented panzootic that followed, have stimulated a major research effort in the western hemisphere and a new interest in the presence of this virus in the Old World. This review considers current understanding of the natural history of this pathogen, with particular regard to transmission in Europe.