Ocular Manifestations of West Nile Virus

Ocular manifestations of West Nile virus infection: A case report and systematic review of the literature

PURPOSE

To report the case of a patient with ocular West Nile virus infection (WNVI) and to describe the demographics, eye characteristics, and treatment of patients with WNVI reported in the literature.

METHODS

Systematic literature search using the PubMed MEDLINE database searching for all cases of ocular WNVI published from inception until October 14, 2023. Inclusion criteria were patients with serologic and/or cerebrospinal fluid diagnosis of WNVI with ocular involvement.

RESULTS

A total of 60 patients (111 eyes), including the present case, were included. Most patients were males (57%), diagnosed in the United States (77%), and with a mean age at presentation of 54 years. The median time elapsed between the viral prodrome, and eye symptoms was 7 days. Neurologic involvement was present in 47 (78%) patients. Diabetes mellitus was the most frequent systemic comorbidity (45%). Posterior segment findings were present in 107 (96%) eyes. Multifocal chorioretinal lesions (86%), vitreous inflammation (51%), intraretinal hemorrhages (43%), and retinal vasculitis (21%) were the most frequent findings. Fluorescein angiography was performed in 88 (79%) eyes. Fifty-seven (51%) eyes did not receive treatment. Topical and systemic steroids were prescribed to 35% and 28% of eyes, respectively.

CONCLUSION

WNVI should be considered as a potential diagnosis in older patients who exhibit posterior uveitis, especially if they have recently experienced flu-like symptoms and have been exposed to mosquitoes. A comprehensive ocular assessment, which includes a dilated fundus examination and ocular imaging studies, can help raise suspicion for this condition even before serological confirmation is obtained.

Ocular manifestations of West Nile virus

PURPOSE OF REVIEW

Over the past two decades, the ophthalmic manifestations of West Nile virus have been more clearly established in the literature. This review aims to summarize its diagnosis and pathogenesis, with a focus on its clinical appearance, characteristic imaging features, and management.

RECENT FINDINGS

Ocular manifestations of West Nile virus present early in the disease course and are more common in cases with severe neurological involvement. The use of optical coherence tomography (OCT), optical coherence tomography angiography (OCT-A), fundus autofluorescence (FAF), fluorescein angiogram (FA), and indocyanine green angiography (ICGA) can aid in its diagnosis and management.

SUMMARY

West Nile virus infection may present with ocular findings that include anterior uveitis, vitritis, retinitis, chorioretinitis, and optic neuropathy; visual prognosis can range from excellent to poor depending on severity of involvement and the presence of secondary complications, such as occlusive vasculitis and macular ischemia. Diagnosis may be aided by multimodal imaging assessment. The ophthalmologist should have a high clinical suspicion for ocular involvement in cases of severe systemic disease.

Viral Anterior Uveitis: A Practical and Comprehensive Review of Diagnosis and Treatment

Anterior uveitis is the most common type of uveitis worldwide. The etiologies of anterior uveitis can be divided into infectious and non-infectious (idiopathic, autoimmune, autoinflammatory, trauma, and others). The viral pathogens most commonly associated with infectious anterior uveitis include Herpes Simplex Virus, Varicella-Zoster Virus, Cytomegalovirus, and Rubella Virus. Other emerging causes of viral anterior uveitis are West Nile Virus, Human-Immunodeficiency Virus, Epstein-Barr Virus, Parechovirus, Dengue Virus, Chikungunya Virus, and Human Herpesvirus type 6,7, and 8. Early recognition allows prompt management and mitigates its potential ocular complications. This article provides an updated literature review of the epidemiology, clinical manifestations, diagnostic tools, and treatment options for viral anterior uveitis.

Infectious eye disease in the 21st century-an overview

Infectious diseases affecting the eye often cause unilateral or asymmetric visual loss in children and people of working age. This group of conditions includes viral, bacterial, fungal and parasitic diseases, both common and rare presentations which, in aggregate, may account for a significant portion of the global visual burden. Diagnosis is frequently challenging even in specialist centres, and many disease presentations are highly regional. In an age of globalisation, an understanding of the various modes of transmission and the geographic distribution of infections can be instructive to clinicians. The impact of eye infections on global disability is currently not sufficiently captured in global prevalence studies on visual impairment and blindness, which focus on bilateral disease in the over-50s. Moreover, in many cases it is hard to differentiate between infectious and immune-mediated diseases. Since infectious eye diseases can be preventable and frequently affect younger people, we argue that in future prevalence studies they should be considered as a separate category, including estimates of disability-adjusted life years (DALY) as a measure of overall disease burden. Numbers of ocular infections are uniquely affected by outbreaks as well as endemic transmission, and their control frequently relies on collaborative partnerships that go well beyond the remit of ophthalmology, encompassing domains as various as vaccination, antibiotic development, individual healthcare, vector control, mass drug administration, food supplementation, environmental and food hygiene, epidemiological mapping, and many more. Moreover, the anticipated impacts of global warming, conflict, food poverty, urbanisation and environmental degradation are likely to magnify their importance. While remote telemedicine can be a useful aide in the diagnosis of these conditions in resource-poor areas, enhanced global reporting networks and artificial intelligence systems may ultimately be required for disease surveillance and monitoring.

Lessons Learned from West Nile Virus Infection:Vaccinations in Equines and Their Implications for One Health Approaches

Humans and equines are two dead-end hosts of the mosquito-borne West Nile virus (WNV) with similar susceptibility and pathogenesis. Since the introduction of WNV vaccines into equine populations of the United States of America (USA) in late 2002, there have been only sporadic cases of WNV infection in equines. These cases are generally attributed to unvaccinated and under-vaccinated equines. In contrast, due to the lack of a human WNV vaccine, WNV cases in humans have remained steadily high. An average of 115 deaths have been reported per year in the USA since the first reported case in 1999. Therefore, the characterization of protective immune responses to WNV and the identification of immune correlates of protection in vaccinated equines will provide new fundamental information about the successful development and evaluation of WNV vaccines in humans. This review discusses the comparative epidemiology, transmission, susceptibility to infection and disease, clinical manifestation and pathogenesis, and immune responses of WNV in humans and equines. Furthermore, prophylactic and therapeutic strategies that are currently available and under development are described. In addition, the successful vaccination of equines against WNV and the potential lessons for human vaccine development are discussed.

Bilateral multifocal chorioretinitis as the only presentation of acute West Nile virus infection: a case report

BACKGROUND

To describe a case of bilateral multifocal chorioretinitis as the only presentation of acute West Nile virus (WNV) infection in the absence of neurological involvement.

CASE PRESENTATION

A 78-year-old Italian woman was admitted to our emergency department because she noticed blurry vision in both eyes. She did not report fever, fatigue, or neurological symptoms in the last few days. Multimodal imaging showed the presence of bilateral hyperfluorescent lesions with a linear distribution, that corresponded to hypocyanescent spots on indocyanine green angiography. Antibody serology showed the presence of IgM antibodies, IgG antibodies, and ribonucleic acid (RNA) for WNV. Magnetic resonance imaging (MRI) of the brain ruled out central nervous system involvement. Three months later, the patient reported spontaneous resolution of her symptoms and remission of the chorioretinal infiltrates.

CONCLUSIONS

In endemic areas, it is important to think of acute WNV infection as an explanatory etiology in cases of multifocal chorioretinitis, even without neurological involvement.

Emerging Disease of the Desert: Rise of West Nile Virus Chorioretinitis in Arizona

Purpose: To present 7 cases of West Nile virus (WNV)-related chorioretinitis in Arizona. Methods: Retina clinic charts with the terms "chorioretinitis" and "West Nile" were selected from April 1, 2012, to February 1, 2023. Results: Seven patients with initial visits between August 2019 and February 2023 were included. The majority of WNV chorioretinitis cases were seen in the last 4 years of the selected dates. Only 1 patient presented before this time but was excluded for inadequate baseline testing. All 7 patients had hospitalization for neuroinvasive disease before clinical presentation. All patients achieved a final visual acuity of 20/25 to 20/70. Conclusions: In the last 4 years of the study period, an uptrend in WNV chorioretinitis was found in our retina clinics in Arizona, reflecting the overall rise in WNV outbreaks across the state. As WNV continues to rise, the eye specialist should have high suspicion for WNV ocular disease, even in states where WNV had been an uncommon entity.

Viral infections and pathogenesis of glaucoma: a comprehensive review

Glaucoma is a leading cause of irreversible blindness worldwide, caused by the gradual degeneration of retinal ganglion cells and their axons. While glaucoma is primarily considered a genetic and age-related disease, some inflammatory conditions, such as uveitis and viral-induced anterior segment inflammation, cause secondary or uveitic glaucoma. Viruses are predominant ocular pathogens and can impose both acute and chronic pathological insults to the human eye. Many viruses, including herpes simplex virus, varicella-zoster virus, cytomegalovirus, rubella virus, dengue virus, chikungunya virus, Ebola virus, and, more recently, Zika virus (ZIKV) and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), have been associated with sequela of either primary or secondary glaucoma. Epidemiological and clinical studies suggest the association between these viruses and subsequent glaucoma development. Despite this, the ocular manifestation and sequela of viral infections are not well understood. In fact, the association of viruses with glaucoma is considered relatively uncommon in part due to underreporting and/or lack of long-term follow-up studies. In recent years, literature on the pathological spectrum of emerging viral infections, such as ZIKV and SARS-CoV-2, has strengthened this proposition and renewed research activity in this area. Clinical studies from endemic regions as well as laboratory and preclinical investigations demonstrate a strong link between an infectious trigger and development of glaucomatous pathology. In this article, we review the current understanding of the field with a particular focus on viruses and their association with the pathogenesis of glaucoma.

Ocular Manifestations of Flavivirus Infections

Flaviviruses are a group of positive-sense, single-stranded RNA viruses predominantly transmitted by arthropods (mainly mosquitoes) that cause severe endemic infections and epidemics on a global scale. They represent a major cause of systemic morbidity and death and are expanding worldwide. Among this group, dengue fever, the West Nile virus, yellow fever, Japanese Encephalitis, and, recently, the Zika virus have been linked to a spectrum of ocular manifestations. These manifestations encompass subconjunctival hemorrhages and conjunctivitis, anterior and posterior uveitis (inclusive of vitritis, chorioretinitis, and retinal vasculitis), maculopathy, retinal hemorrhages, and optic neuritis. Clinical diagnosis of these infectious diseases is primarily based on epidemiological data, history, systemic symptoms and signs, and the pattern of ocular involvement. Diagnosis confirmation relies on laboratory testing, including RT-PCR and serological testing. Ocular involvement typically follows a self-limited course but can result in irreversible visual impairment. Effective treatments of flavivirus infections are currently unavailable. Prevention remains the mainstay for arthropod vector and zoonotic disease control. Effective vaccines are available only for the yellow fever virus, dengue virus, and Japanese Encephalitis virus. This review comprehensively summarizes the current knowledge regarding the ophthalmic manifestations of the foremost flavivirus-associated human diseases.

Diplopia, COVID-19 and Vaccination: Results from a Cross-Sectional Study in Croatia

The aim of this study was to explore diplopia as a symptom of undetected COVID-19 infection or as a possible side effect of COVID-19 vaccination. We examined 380 patients with diplopia admitted to the Department of Ophthalmology of the University Hospital Centre Sestre milosrdnice in Zagreb, Croatia, from July 2020 to June 2022. After excluding patients with confirmed organic underlying diplopia causes or monocular diplopia, we linked the patient information with the national COVID-19 and vaccination registries. Among the 91 patients included in this study, previously undetected COVID-19 infection as the possible cause of diplopia was confirmed in five of them (5.5%). An additional nine patients (9.9%) were vaccinated within one month from the onset of their symptoms, while the remaining 77 had neither and were therefore considered as controls. The breakdown according to the mechanism of diplopia showed no substantial difference between the vaccinated patients and the controls. We detected marginally insignificant excess abducens nerve affection in the COVID-positive group compared with that in the controls (p = 0.051). Post-vaccination diplopia was equally common in patients who received vector-based or RNA-based vaccines (21.4 vs. 16.7%; p = 0.694). COVID-19 testing should be performed for all cases of otherwise unexplained diplopia. The risk of post-vaccination diplopia was similar in both types of vaccines administered, suggesting a lack of evidence linking specific vaccine types to diplopia.

Nervous System Manifestations of Arboviral Infections

Purpose of Review

Complex environmental factors and human intervention influence the spread of arthropod vectors and the cycle of transmission of arboviruses. The spectrum of clinical manifestations is diverse, ranging from serious presentations like viral hemorrhagic fever (e.g., dengue, yellow fever, rift valley fever) or shock syndromes (e.g., dengue virus) to organ-specific illness like meningoencephalitis.

Recent Findings

A spectrum of clinical neurologic syndromes with potential acute devastating consequences or long-term sequelae may result from some arboviral infections.

Summary

In this review, we describe some of the most frequent and emerging neuro-invasive arboviral infections, spectrum of neurologic disorders including encephalitis, meningitis, myelitis or poliomyelitis, acute demyelinating encephalomyelitis, Guillain-Barré syndrome, and ocular syndromes.

Autochthonous West Nile Virus Infection Outbreak in Humans (Asti, Piedmont, Italy, August–October 2018) and Long-Term Sequelae Follow-Up

West Nile virus (WNV) infection is a reemerging zoonosis recently provoking significant outbreaks throughout Europe. During the summer of 2018, the number of WNV infections rose with a peak of new diagnoses of West Nile neuro-invasive disease (WNND). Most of the Italian cases were clustered in the Po River Valley. We present a case series of nine patients with WNV infection admitted to the Cardinal Massaia Hospital from 30 August 2018 to 1 October 2018. Demographic, immunovirological, clinical and therapeutic data are shown, and a report on clinical sequelae from the subsequent follow-up in patients with WNV and WNND. We showed the clinical, radiological and biochemical characteristics of WNV-infected patients. The risk factors and the clinical presentation of WNV in most patients in our case series were typical of that described in the literature, although, despite the high morbidity and mortality of WNND, we showed survival of 100% and long-term sequelae in only three patients. Environmental conditions may be essential in WNV outbreaks, and WNND can be clinically neurological multiform. Our long-lasting follow-up with clinical or radiological monitoring confirmed the morbidity of long-term neurological sequelae after WNND. Further studies are needed to investigate the epidemiology and physiopathology of bacterial superinfections after WNV infection.

Occlusive retinal vasculitis: novel insights into causes, pathogenesis and treatment

PURPOSE OF REVIEW

Occlusive retinal vasculitis (ORV) has a large differential diagnosis and varied therapeutic approaches. This review highlights existing and novel causes and treatment options for ORV.

RECENT FINDINGS

Mutations in CAPN5, TREX1, and TNFAIP3 have been associated with dominantly inherited forms of ORV. Various intraocular therapeutics have been shown to occasionally cause ORV; the most recent medications associated with ORV are vancomycin and brolucizumab. In cases of ORV linked to Behçet's disease, clinical trials support the use of tumor necrosis factor alpha inhibitors.

SUMMARY

Identification of the underlying etiology of ORV is critical to help guide treatment. Treatment in ORV involves both treatment any underlying infection or autoimmune condition, cessation of the any offending causative agent and local treatment of neovascular complications.