Prediction of unfavorable outcomes in West Nile virus neuroinvasive infection - Result of a multinational ID-IRI study

West Nile Virus Outbreak in Israel 2024 Compared with Previous Seasons: A Retrospective Study

INTRODUCTION

Since May 2024, Israel has been experiencing a large West Nile virus (WNV) outbreak. We aimed to compare the clinical characteristics and outcomes of hospitalized cases to previous years and identify predictors of poor outcomes.

METHODS

A retrospective study. We compared WNV infection cases hospitalized during the 2024 outbreak (from 29 May to 29 July) to cases hospitalized during 2018-2023. For the entire cohort, risk factors for poor outcomes were investigated using multivariable analyses. The primary outcomes were death and a composite outcome of 30-day all-cause mortality, prolonged hospitalization (≥ 28 days), or discharge to an institution.

RESULTS

We included 134 patients, 103 admitted during 2024 and 31 during 2018-2023. The majority (109/134, 81%) had neuroinvasive disease, mostly encephalitis. In 2024, patients were older, with a lower functional state, and a higher proportion were severely immunocompromised. Mortality was numerically higher in 2024 (15/103, 15% versus 2/31, 6%). Altogether, nearly 40% of patients had poor outcomes, including 13% (17/134) mortality and 25% (34/134) discharged to institutions. Nearly 30% of patients who were severely immunocompromised died; all had B-cell depletion. Age was the only significant predictor of poor outcomes in multivariable analysis; however, patients with B-cell depletion had > 3 times higher odds for mortality (odds ratio 3.26, 95% confidence interval 0.73-13.07).

CONCLUSIONS

The large 2024 outbreak of WNV was associated with considerable mortality and functional impairment among hospitalized patients that was higher compared with previous years. Poor outcomes were particularly observed in older adults and patients with B-cell depletion. The observation of severe disease and poor outcomes in patients with B-cell depletion, as well as possible therapeutic implications, should be further investigated.

West Nile Virus Encephalitis in a Patient with Chronic Lymphocytic Leukemia

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West Nile virus encephalitis: Clinical characteristics and a comparison to other infectious encephalitides

PURPOSE

To compare functional outcomes and help differentiate between important causative agents of acute infectious encephalitis in adults, focusing on West Nile virus encephalitis (WNVE).

METHODS

The electronic database of Tel Aviv Medical Center was screened for patients admitted during 2010-2020 with acute encephalitis. Additionally, patient laboratory results during the same period were screened for CSF samples positive for common pathogens causing encephalitis. The main patient groups were compared in terms of clinical characteristics and functional outcomes.

RESULTS

One hundred and five infectious encephalitis patients were identified. WNVE patients (n = 31) and VZV encephalitis (VZVE) patients (n = 31) were older than HSV1 encephalitis (HSV1E) patients (n = 15) (median ages 73, 76, 51, respectively). WNVE patients had a more prominent inflammatory profile. CSF characteristics significantly differed between groups, with an extreme mononuclear white blood cell predominance in VZVE patients (median 98%). Functional outcomes at discharge were significantly worse in WNVE patients (median modified Rankin Scale score 4 at hospital discharge, 2.5 at last follow-up) when compared with HSV1E patients (2.5, 1, respectively) and VZVE patients (1.5, 1, respectively).

CONCLUSION

In odds with previous reports, WNVE and VZVE in this study were far more prevalent than HSV1E. Differences in clinical characteristics could prove clinically useful early in encephalitis, including an association of WNVE with a relatively prominent inflammatory profile (somewhat resembling a bacterial infection) and an extreme mononuclear white blood cell predominance in VZVE. The detrimental outcome of WNVE emphasizes the need to advance research on WNV infection.

West Nile Virus Neuroinvasive Disease: Lessons From Two Cases

BACKGROUND AND OBJECTIVE

West Nile neuroinvasive disease (WNND) displays a wide range of clinical manifestations due to its involvement of various structures within the central nervous system and peripheral nervous system, often including prolonged unresponsiveness as the presenting symptom.

METHODS AND RESULTS

We describe 2 patients presenting with coma and bilateral thalamic lesions on brain magnetic resonance imaging, found to have WNND after extensive workup. These cases illustrate some of the challenges associated with evaluating coma in general and specifically in diagnosing WNND.

CONCLUSION

The clinical diagnosis of WNND requires a high index of suspicion, particularly in immunocompromised and elderly patients. Brain and spine magnetic resonance imaging findings can help narrow down the differential diagnosis, although other diseases may manifest similarly. Serological studies on the cerebrospinal fluid are essential to confirm the diagnosis but have inherent limitations. Given these challenges, WNND should be considered in all patients living in endemic areas who present with unexplained altered mental status during the late summer and early fall seasons.

A Case of West Nile Virus Neuroinvasive Disease Presenting With Isolated Diplopia

West Nile virus (WNV) is a single-stranded RNA virus causing a wide spectrum of diseases. Neuroinvasive conditions such as meningitis and encephalitis are feared complications of WNV infection. Here, we describe the case of a 78-year-old male whose only initial presenting symptoms were fever and transient diplopia, whose initial MRI imaging with and without contrast did not reveal any abnormalities. He was discharged, only to return to care the next day; lumbar puncture was performed suggesting bacterial meningitis, and he was admitted and given antibiotics. Repeat MRI was negative, and he developed an altered mental status requiring intubation. WNV neuroinvasive disease was subsequently found after serology was performed. Supportive care was given, and he made a full recovery with no residual deficits. This case highlights an unusual presentation of WNV encephalitis and highlights the difficulty that can be present in diagnosing this disease.

Demographic characteristics associated with West Nile virus neuroinvasive disease - A retrospective study on the wider European area 2006-2021

BACKGROUND

With a case-fatality-risk ranging from 3.0 to >20.0% and life-long sequelae, West Nile neuroinvasive disease (WNND) is the most dangerous outcome of West Nile virus (WNV) infection in humans. As no specific prophylaxis nor therapy is available for these infections, focus is on preventive strategies. We aimed to find variables associated with WNND diagnosis, hospitalisation or death, to identify high-risk sub-groups of the population, on whom to concentrate these strategies.

METHODS

We used data from The European Surveillance System-TESSy, provided by National Public Health Authorities, and released by the European Centre for Disease Prevention and Control (ECDC). In two Firth-penalised logistic regression models, we considered age, sex, clinical criteria, epidemiological link to other cases (epi-link), calendar year, and season as potential associated variables. In one model we considered also the rural/urban classification of the place of infection (RUC), while in the other the specific reporting country.

FINDINGS

Among confirmed West Nile Virus cases, 2,916 WNND cases were registered, of which 2,081 (71.4%), and 383 (13.1%) resulted in the hospitalisation and death of the patient, respectively. Calendar year, RUC/country, age, sex, clinical criteria, and epi-link were associated with WNND diagnosis. Hospitalisation was associated with calendar year and RUC/country; whereas death was associated with age, sex and country.

INTERPRETATION

Our results support previous findings on WNND associated variables (most notably age and sex); while by observing the whole population of WNND cases in the considered area and period, they also allow for stronger generalizations, conversely to the majority of previous studies, which used sample populations.

Comparison of West Nile Virus Disease in Humans and Horses: Exploiting Similarities for Enhancing Syndromic Surveillance

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.

Arthropod-Borne Flaviviruses in Pregnancy

Flaviviruses are a diverse group of enveloped RNA viruses that cause significant clinical manifestations in the pregnancy and postpartum periods. This review highlights the epidemiology, pathophysiology, clinical features, diagnosis, and prevention of the key arthropod-borne flaviviruses of concern in pregnancy and the neonatal period-Zika, Dengue, Japanese encephalitis, West Nile, and Yellow fever viruses. Increased disease severity during pregnancy, risk of congenital malformations, and manifestations of postnatal infection vary widely amongst this virus family and may be quite marked. Laboratory confirmation of infection is complex, especially due to the reliance on serology for which flavivirus cross-reactivity challenges diagnostic specificity. As such, a thorough clinical history including relevant geographic exposures and prior vaccinations is paramount for accurate diagnosis. Novel vaccines are eagerly anticipated to ameliorate the impact of these flaviviruses, particularly neuroinvasive disease manifestations and congenital infection, with consideration of vaccine safety in pregnant women and children pivotal. Moving forward, the geographical spread of flaviviruses, as for other zoonoses, will be heavily influenced by climate change due to the potential expansion of vector and reservoir host habitats. Ongoing 'One Health' engagement across the human-animal-environment interface is critical to detect and responding to emergent flavivirus epidemics.

Neuroinvasive disease due to West Nile virus: Clinical and imaging findings associated with a re-emerging pathogen

The West Nile virus (WNV) is an arbovirus than can infect human beings and cause severe neuroinvasive disease. Taking the outbreak that occurred in Spain in 2020 as a reference, this article reviews the clinical and imaging findings for neuroinvasive disease due to WNV. We collected demographic, clinical, laboratory, and imaging (CT and MRI) variables for 30 patients with WNV infection diagnosed at our center. The main clinical findings were fever, headache, and altered levels of consciousness. Neuroimaging studies, especially MRI, are very useful in the diagnosis and follow-up of these patients. The most common imaging findings were foci of increased signal intensity in the thalamus and brainstem in T2-weighted sequences; we illustrate these findings in cases from our hospital.

Cognitive decline following acute viral infections: literature review and projections for post-COVID-19

Recently, much attention has been drawn to the importance of the impact of infectious disease on human cognition. Several theories have been proposed, to explain the cognitive decline following an infection as well as to understand better the pathogenesis of human dementia, especially Alzheimer's disease. This article aims to review the state of the art regarding the knowledge about the impact of acute viral infections on human cognition, laying a foundation to explore the possible cognitive decline followed coronavirus disease 2019 (COVID-19). To reach this goal, we conducted a narrative review systematizing six acute viral infections as well as the current knowledge about COVID-19 and its impact on human cognition. Recent findings suggest probable short- and long-term COVID-19 impacts in cognition, even in asymptomatic individuals, which could be accounted for by direct and indirect pathways to brain dysfunction. Understanding this scenario might help clinicians and health leaders to deal better with a wave of neuropsychiatric issues that may arise following COVID-19 pandemic as well as with other acute viral infections, to alleviate the cognitive sequelae of these infections around the world.

Update on Viral Infections Involving the Central Nervous System in Pediatric Patients

Infections of the central nervous system (CNS) are mainly caused by viruses, and these infections can be life-threatening in pediatric patients. Although the prognosis of CNS infections is often favorable, mortality and long-term sequelae can occur. The aims of this narrative review were to describe the specific microbiological and clinical features of the most frequent pathogens and to provide an update on the diagnostic approaches and treatment strategies for viral CNS infections in children. A literature analysis showed that the most common pathogens worldwide are enteroviruses, arboviruses, parechoviruses, and herpesviruses, with variable prevalence rates in different countries. Lumbar puncture (LP) should be performed as soon as possible when CNS infection is suspected, and cerebrospinal fluid (CSF) samples should always be sent for polymerase chain reaction (PCR) analysis. Due to the lack of specific therapies, the management of viral CNS infections is mainly based on supportive care, and empiric treatment against herpes simplex virus (HSV) infection should be started as soon as possible. Some researchers have questioned the role of acyclovir as an empiric antiviral in older children due to the low incidence of HSV infection in this population and observed that HSV encephalitis may be clinically recognizable beyond neonatal age. However, the real benefit-risk ratio of selective approaches is unclear, and further studies are needed to define appropriate indications for empiric acyclovir. Research is needed to find specific therapies for emerging pathogens. Moreover, the appropriate timing of monitoring neurological development, performing neuroimaging evaluations and investigating the effectiveness of rehabilitation during follow-up should be evaluated with long-term studies.

Neuroinvasive disease due to West Nile virus: clinical and imaging findings associated with a re-emerging pathogen

The West Nile virus (WNV) is an arbovirus than can infect human beings and cause severe neuroinvasive disease. Taking the outbreak that occurred in Spain in 2020 as a reference, this article reviews the clinical and imaging findings for neuroinvasive disease due to WNV. We collected demographic, clinical, laboratory, and imaging (CT and MRI) variables for 30 patients with WNV infection diagnosed at our center. The main clinical findings were fever, headache, and altered levels of consciousness. Neuroimaging studies, especially MRI, are very useful in the diagnosis and follow-up of these patients. The most common imaging findings were foci of increased signal intensity in the thalamus and brainstem in T2-weighted sequences; we illustrate these findings in cases from our hospital.

Identifying risks for severity of neurological symptoms in Hungarian West Nile virus patients

BACKGROUND

West Nile virus (WNV) infections have become increasingly prevalent in certain European countries, including Hungary. Although most human infections do not cause severe symptoms, in approximately 1% of cases WNV infections can lead to severe WNV neuroinvasive disease (WNND) and death. The goal of our study was to assess the neurological status changes of WNV -infected patients admitted to inpatient care and to identify potential risk factors as underlying reasons for severe neurological outcome.

METHODS

We conducted a retrospective chart review of 66 WNV-infected patients from four Hungarian medical centers. Patients' neurological status at hospital admission and at two follow-up intervals (1st follow-up, within 60-90 days and 2nd follow-up, within 150-180 days, after hospital discharge) were assessed. All of the 66 patients in the initial sample had some type of neurological symptoms and 56 patients were diagnosed with WNND. The modified Rankin Scale (mRS) and the West Nile Virus Neurological Index (WNV-N Index), a scoring system designed for the purpose of this study, were used for neurological status assessment. Patients were dichotomized into two categories, "moderately severe" and "severe" based on their neurological status. Descriptive analysis for sample description, stratified analysis for calculation of odds ratio (OR) and logistic regression for continuous input variables, were performed.

RESULTS

The average number of days between the onset of neurological symptoms and hospital admission (the neurological symptom interval) was 6.01 days. Complications during the hospital stay arose in almost a fifth of the patients (18.2%) and 5 patients died. Each day's increase in the neurological symptom interval significantly increased the risk for developing a severe neurological status following hospital admission (0.799-fold and 0.688-fold, based on the WNV-N Index and mRS, respectively). Patients' age, comorbidity, presence of complications and symptoms of malaise, and gait uncertainty were shown to be independent risk factors for severe neurological status.

CONCLUSIONS

Timely hospital admission of patients with neurological symptoms as well as risk assessment by clinicians - possibly with an optimal assessment tool for estimating neurological status- could improve the neurological outcome of WNV-infected patients.

Predicting Inpatient Mortality Among Encephalitis Patients: A Novel Admission Risk Score

Background

Identifying underlying commonalities among all-cause encephalitis cases can be extraordinarily useful in predicting meaningful risk factors associated with inpatient mortality.

Methods

A retrospective cohort of patients with encephalitis was derived from a clinical chart review of adult patients (age ≥18 years) across 16 different hospitals in Houston, Texas, between January 2005 and July 2015. Clinical features at admission were assessed for their correlation with inpatient mortality and used to derive a final risk score prediction tool.

Results

The study included a total of 273 adult patients with all-cause encephalitis, 27 (9.9%) of whom died during hospitalization. A limited number of clinical features were substantially different between patients who survived and those who died (Charlson score, Glasgow coma scale [GCS], immunosuppression, fever on admission, multiple serologic studies, and abnormal imaging). A final multivariable logistic model was derived with the following risk factors, which were transformed into a scoring system: 1 point was assigned to the presence of a Charlson score >2, thrombocytopenia, or cerebral edema, and 2 points for a GCS value <8. Patients were then classified into different risk groups for inpatient mortality: 0 points (0%), 1 point (7%), 2 points (10.9%), 3 points (36.8%), and ≥4 points (81.8%).

Conclusions

The risk score developed from this study shows a high predictive value. This can be highly beneficial in alerting care providers to key clinical risk factors associated with in-hospital mortality in adults with encephalitis.