Ocular manifestations of emerging arboviruses: Dengue fever, Chikungunya, Zika virus, West Nile virus, and yellow fever

An improved alphaviruses-specific RT-qPCR facilitates monitoring and prevention of alphaviruses

Molecular surveillance is vital for monitoring arboviruses, often employing genus-specific quantitative reverse-transcription polymerase chain reaction (RT-qPCR). Despite this, an overlooked chikungunya fever outbreak occurred in Yunnan province, China, in 2019 and false negatives are commonly encountered during alphaviruses screening practice, highlighting the need for improved detection methods. In this study, we developed an improved alphaviruses-specific RT-qPCR capable of detecting chikungunya virus, eastern equine encephalitis virus, western equine encephalitis virus, Venezuelan equine encephalitis virus, Sindbis virus, Mayaro virus, and Ross River virus with high sensitivity and specificity. The assay identified three chikungunya virus-positive cases out of 188 sera retrospectively. Later genetic characterization suggested that imported cases from neighboring countries may be responsible for the neglected chikungunya fever outbreak of 2019 in Yunnan. Our findings underscore the value of improved alphaviruses-specific RT-qPCR in bolstering alphaviruses surveillance and informing preventive strategies.

[Vasculitis of the retina : Clinical aspects, diagnostics, management and treatment]

Inflammatory changes in the retinal vessels can be attributed to a wide range of etiologies. These include infections, intraocular and systemic autoimmune processes, general diseases and iatrogenic factors. As the endothelium of the retinal capillaries forms the inner blood-retinal barrier, a disruption of this structure is directly associated with consequences for the fluid electrolyte balance of the retina. Clinical sequelae can include leakage of the retinal vessels and macular edema, which are often functionally threatening and significantly reduce the quality of life of patients. As the eye can be affected as an "index organ", a work-up of the patient by the ophthalmologist is of great importance. In the age of "precision medicine", efforts are being made to gain new insights into the pathogenetic mechanisms of vasculitis through "omics" in order to develop innovative treatment concepts.

Peptide-Based Flavivirus Biosensors: From Cell Structure to Virological and Serological Detection Methods

In tropical and developing countries, mosquito-borne diseases by flaviviruses pose a serious threat to public health. Early detection is critical for preventing their spread, but conventional methods are time-consuming and require skilled technicians. Biosensors have been developed to address this issue, but cross-reactivity with other flaviviruses remains a challenge. Peptides are essentially biomaterials used in diagnostics that allow virological and serological techniques to identify flavivirus selectively. This biomaterial originated as a small protein consisting of two to 50 amino acid chains. They offer flexibility in chemical modification and can be easily synthesized and applied to living cells in the engineering process. Peptides could potentially be developed as robust, low-cost, sensitive, and selective receptors for detecting flaviviruses. However, modification and selection of the receptor agents are crucial to determine the effectiveness of binding between the targets and the receptors. This paper addresses two potential peptide nucleic acids (PNAs) and affinity peptides that can detect flavivirus from another target-based biosensor as well as the potential peptide behaviors of flaviviruses. The PNAs detect flaviviruses based on the nucleotide base sequence of the target's virological profile via Watson-Crick base pairing, while the affinity peptides sense the epitope or immunological profile of the targets. Recent developments in the functionalization of peptides for flavivirus biosensors are explored in this Review by division into electrochemical, optical, and other detection methods.

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.

Systemic and Ophthalmic Manifestations of Chikungunya Fever

PURPOSE

Chikungunya is a re-emerging viral infection across the globe. The purpose of this article is to review the systemic and ophthalmic manifestations associated with chikungunya fever.

METHOD

A review of literature was conducted using online databases.

RESULTS

In this report, we have reviewed the presently available literature on uveitis caused by chikungunya and highlighted the current knowledge of its clinical manifestations, imaging features, laboratory diagnostics, and the available therapeutic modalities from the systemic and ophthalmic standpoint.

CONCLUSIONS

Ocular involvement in chikungunya infection may occur at the time of systemic manifestations or it may occur as a delayed presentation many weeks after the fever. Treatment relies on a supportive therapy for systemic illness. Treatment of ocular manifestation depends on the type of manifestations and usually includes a combination of topical and oral steroids.

Ophthalmic complications during the dengue epidemic in Reunion Island in 2020: a case series and review of the literature

INTRODUCTION

Dengue is an arboviral disease transmitted by the dengue virus, whose vectors are Aedes aegypti and Aedes albopictus. The acute phase with its cohort of well-known symptoms is usually spontaneously favorable. Since 2020 in Reunion Island, a new symptom has appeared: the ocular damage of dengue fever, which has already been described in South Asia and South-East Asia. We therefore decided to describe the clinical, biological, ophthalmological, therapeutic, and outcomes of patients with ocular manifestations during dengue fever in Reunion Island in 2020.

PATIENTS AND METHODS

This was a retrospective observational study. Patients were included from January 2020 to August 2020 and then reassessed by teleconsultation 1 year later. The patients were identified from the French public health surveillance network by all ophthalmologists on the island. Medical data were collected directly from medical records.

RESULTS

Twenty-eight patients were included. The mean age was 41.9 years. Ocular involvement occurred approximately 9.2 days after the onset of dengue symptoms. The main symptoms were scotoma (71.4%) and sudden decrease of visual acuity (39.2%). Eighteen patients (64.2%) had macular involvement. Fourteen patients were treated with oral or intravenous corticosteroids. Twenty-two (78.5%) patients were evaluated by telephone one year later. Scotoma and decreased visual acuity persisted in 15 patients. Thirteen patients (59%) were bothered by night driving, 32% of patients had reading difficulties and 27% of patients became sensitive to prolonged exposure to screens.

CONCLUSION

Ocular complications of dengue require early and collegial management to limit the risk of long-term sequelae. Further studies on the characteristics and complications of dengue fever are needed to better understand this disease.

Discovery and structure-activity relationship of Morita-Baylis-Hillman adducts as larvicides against dengue mosquito vector, Aedes aegypti (Diptera: Culicidae)

Neglected tropical diseases (NTDs) have become a significant public health problem worldwide, notably the life-threatening dengue hemorrhagic fever borne by the Aedes aegypti mosquito. Thus, mosquito vector control measures remain essential in public health vector surveillance and control to combat Aedes-borne infections. Therefore, a series of MBH adducts were synthesized and assessed towards the fourth instar mosquito larvae, Aedes aegypti, along with the preliminary structure-activity relationship (SAR). Noteworthy, this compound class might be synthetized by an efficient eco-friendly synthesismethod and a rapid route for the synthesis of commercial larvicide through a single synthetic step. The bioassays showed that this compound class is a promising larvicide to control Aedes aegypti mosquito larvae, mainly 3g, with an LC₅₀ of 41.35 µg/mL, which was higher than evaluated positive controls. Nevertheless, it is a viable larvicidalhit candidate for further hit-to-leadproperties optimization of its biphenyl backbone scaffold with enhanced insecticidalbioactivity. Moreover, scanning electron microscopy analysis suggested a disruption of the osmoregulatory/ionoregulatory functions by the complete deterioration of the terminal exoskeleton hindgut and anal papillae. Therefore, this new study shows the larvicidal efficacy of the tested compounds against the Aedes aegypti larvae.

Zika virus infection of retinal cells and the developing mouse eye induces host responses that contrasts to the brain and dengue virus infection

Zika virus (ZIKV) infection causes ocular and neurological pathologies with ZIKV-induction of developmental abnormalities following in utero infection a major concern. The study here has compared ZIKV and the related dengue virus (DENV) infection in the eye and brain. In vitro, both ZIKV and DENV could infect cell lines representing the retinal pigmented epithelium, endothelial cells, and Mueller cells, with distinct innate responses in each cell type. In a 1-day old mouse challenge model, both ZIKV and DENV infected the brain and eye by day 6 post-infection (pi). ZIKV was present at comparable levels in both tissues, with RNA increasing with time post-infection. DENV infected the brain, but RNA was detected in the eye of less than half of the mice challenged. NanoString analysis demonstrated comparable host responses in the brain for both viruses, including induction of mRNA for myosin light chain-2 (Mly2), and numerous antiviral and inflammatory genes. Notably, mRNA for multiple complement proteins were induced, but C2 and C4a were uniquely induced by ZIKV but not DENV. Consistent with the viral infection in the eye, DENV induced few responses while ZIKV induced substantial inflammatory and antiviral responses. Compared to the brain, ZIKV in the eye did not induce mRNAs such as C3, downregulated Retnla, and upregulated CSF-1. Morphologically, the ZIKV-infected retina demonstrated reduced formation of specific retinal layers. Thus, although ZIKV and DENV can both infect the eye and brain, there are distinct differences in host cell and tissue inflammatory responses that may be relevant to ZIKV replication and disease.

Ophthalmic consequences of viral hemorrhagic fevers: Insights from the clinic and laboratory

Viral hemorrhagic fevers (VHFs) are a diverse group of RNA virus-mediated systemic diseases with significant morbidity and mortality and represent a significant public health concern. Given the high systemic morbidity and mortality in a number of these entities, delays in diagnosis can lead to downstream public health consequences. Many viral hemorrhagic fevers have ophthalmic manifestations and ophthalmologists thus play a key role in disease recognition and the management of ocular complications associated with specific hemorrhagic fevers. This review summarizes the key ophthalmic consequences of viral hemorrhagic fevers, viral disease pathogenesis, disease findings, and areas of unmet research need.

Satellite observation to assess dengue risk due to Aedes aegypti and Aedes albopictus in a subtropical city of Argentina

Earth observation environmental features measured through remote sensing and models of vector mosquitoes species Aedes aegypti and Ae. albopictus provide an advancement with regards to dengue risk in urban environments of subtropical areas of Argentina. The authors aim to estimate the effect of landscape coverage and spectral indices (Normalized Difference Vegetation Index [NDVI], Normalized Difference Water Index [NDWI] and Normalized Difference Built-up Index [NDBI]) on the larvae abundance of Ae. aegypti and Ae. albopictus in Eldorado, Misiones, Argentina using remote satellite sensors. Larvae of these species were collected monthly (June 2016 to April 2018), in four environments: tire repair shops, cemeteries, dwellings and an urban natural park. The proportion of landscape coverage (water, urban areas, bare soil, low vegetation and high vegetation) was determined from the supervised classification of Sentinel-2 images and spectral indices, calculated. The authors developed spatial models of both vector species by generalized linear mixed models. The model's results showed that Ae. aegypti larvae abundance was better modelled by NDVI minimum values, NDBI maximum values and the interaction between them. For Ae. albopictus proportion of bare soil, low vegetation and the interaction between both variables explained better the abundance.

Changing face of non-infectious pediatric uveitis in the pre-pandemic and pandemic periods: a comparison study

OBJECTIVE

Our aim in this study was to reveal the clinical features of pediatric uveitis in the pandemic period and to compare it with the pre-pandemic era.

METHODS

This retrospective study included 187 children diagnosed with uveitis between the 11^th of March 2017 and the 11^th of March 2022. The patients were divided into two groups based on the date of diagnosis as follows; Group 1: Patients diagnosed in the pre-pandemic period (11^th March 2017-11^th March 2020); Group 2: Patients diagnosed in the pandemic period (12^th March 2020-11^th March 2022). Demographic data, characteristics of uveitis, underlying diseases, systemic treatment modalities, and complications were compared between the two groups.

RESULTS

A total of 187 (pre-pandemic 71, and pandemic 114) pediatric uveitis patients were recruited to the study. Fifty one percent (51%) of the patients were female. The number of patients diagnosed with uveitis increased approximately twice during the pandemic period compared to the pre-pandemic period. The frequency of anterior uveitis was found to be significantly higher in the pandemic period than in the pre-pandemic period (p = 0.037). It was mostly presented as symptomatic uveitis. There was a decrease in the diagnosis of JIA-related uveitis. ANA positivity increased in the pandemic period (p = 0.029). The response to treatment was better and the complication rate decreased in the pandemic period.

CONCLUSION

The present study involved a large number of pediatric patients with uveitis. There are some differences in the characteristics of pediatric uveitis cases comparing the pandemic period and the pre-pandemic period. This increased frequency and changing clinical features of pediatric uveitis seems to be a result of COVID-19 infection.

Conjunctival sac microbiome in anophthalmic patients: Flora diversity and the impact of ocular prosthesis materials

Purpose

To explore the changes of bacterial flora in anophthalmic patients wearing ocular prosthesis (OP) and the microbiome diversity in conditions of different OP materials.

Methods

A cross-sectional clinical study was conducted, involving 19 OP patients and 23 healthy subjects. Samples were collected from the upper, lower palpebral, caruncle, and fornix conjunctiva. 16S rRNA sequencing was applied to identify the bacterial flora in the samples. The eye comfort of each OP patient was determined by a questionnaire. In addition, demographics information of each participant was also collected.

Results

The diversity and richness of ocular flora in OP patients were significantly higher than that in healthy subjects. The results of flora species analysis also indicated that in OP patients, pathogenic microorganisms such as Escherichia Shigella and Fusobacterium increased significantly, while the resident flora of Lactobacillus and Lactococcus decreased significantly. Within the self-comparison of OP patients, compared with Polymethyl Methacrylate (PMMA), prosthetic material of glass will lead to the increased colonization of opportunistic pathogens such as Alcaligenes, Dermabacter and Spirochaetes, while gender and age have no significant impact on ocular flora.

Conclusions

The ocular flora of OP patients was significantly different from that of healthy people. Abundant colonization of pathogenic microorganisms may have an important potential relationship with eye discomfort and eye diseases of OP patients. PMMA, as an artificial eye material, demonstrated potential advantages in reducing the colonization of opportunistic pathogens.

Viral Infection and Antiviral Treatments in Ocular Pathologies

Ocular viral infections are common and widespread globally. These infectious diseases are a major cause of acute red eyes and vision loss. The eye and its nearby tissues can be infected by several viral agents, causing infections with a short course and limited ocular implications or a long clinical progression and serious consequences for the function and structure of the ocular region. Several surveillance studies underline the increased emergence of drug resistance among pathogenic viral strains, limiting treatment options for these infections. Currently, in the event of resistant infections, topical or systemic corticosteroids are useful in the management of associated immune reactions in the eye, which contribute to ocular dysfunction. Many cases of viral eye infections are misdiagnosed as being of bacterial origin. In these cases, therapy begins late and is not targeted at the actual cause of the infection, often leading to severe ocular compromises, such as corneal infiltrates, conjunctival scarring, and reduced visual acuity. The present study aims at a better understanding of the viral pathogens that cause eye infections, along with the treatment options available.

Attempts to use breeding approaches in Aedes aegypti to create lines with distinct and stable relative Wolbachia densities

Wolbachia is an insect endosymbiont being used for biological control in the mosquito Aedes aegypti because it causes cytoplasmic incompatibility (CI) and limits viral replication of dengue, chikungunya, and Zika viruses. While the genetic mechanism of pathogen blocking (PB) is not fully understood, the strength of both CI and PB are positively correlated with Wolbachia densities in the host. Wolbachia densities are determined by a combination of Wolbachia strain and insect genotype, as well as interactions with the environment. We employed both artificial selection and inbreeding with the goal of creating lines of Ae. aegypti with heritable and distinct Wolbachia densities so that we might better dissect the mechanism underlying PB. We were unable to shift the mean relative Wolbachia density in Ae. aegypti lines by either strategy, with relative densities instead tending to cycle over a narrow range. In lieu of this, we used Wolbachia densities in mosquito legs as predictors of relative densities in the remaining individual's carcass. Because we worked with outbred mosquitoes, our findings indicate either a lack of genetic variation in the mosquito for controlling relative density, natural selection against extreme densities, or a predominance of environmental factors affecting densities. Our study reveals that there are moderating forces acting on relative Wolbachia densities that may help to stabilize density phenotypes post field release. We also show a means to accurately bin vector carcasses into high and low categories for non-DNA omics-based studies of Wolbachia-mediated traits.

Assessment of Dengue and Chikungunya Infections among Febrile Patients Visiting Four Healthcare Centres in Yaoundé and Dizangué, Cameroon

Dengue and chikungunya are now widely distributed in Cameroon, but there is still not enough information on their prevalence in different epidemiological settings. This study was undertaken to assess the prevalence of dengue and chikungunya in both urban and rural settings in Cameroon using three diagnostic tools. From December 2019 to September 2021, willing febrile (temperature >38 °C) outpatients visiting four healthcare facilities in the cities of Yaoundé and Dizangué were screened for dengue, and chikungunya. Clinical features of patient were recorded in a form, and their blood samples were analysed using real-time reverse transcriptase-polymerase chain reaction (rtRT-PCR), rapid diagnostic tests (RDTs) and enzyme-linked immuno-sorbent assays (ELISA). Odds ratios were used to determine the level of association between socio-demographic factors, clinical features, and infection status. The Kappa coefficient permitted to assess the level of agreement between RDTs and ELISA. Overall, 301 febrile patients were recruited in the study: 198 in Yaoundé and 103 in Dizangué. The prevalence of infection varied with the diagnostic tool used. For dengue diagnostics, 110 patients were positive to rtRT-PCR: 90 (45.45%) in Yaoundé, and 20 (19.42%) in Dizangué. The prevalence of dengue IgM using ELISA varied from 22.3% in Dizangué to 30.8% in Yaoundé. Dengue IgM rate using RDTs was 7.6% in Yaoundé and 3.9% in Dizangué. For chikungunya, one (0.5%) patient (Yaoundé, suburb) was positive to rtRT-PCR. The prevalence of chikungunya IgM according to ELISA varied from 18.4% in Dizangué to 21.7% in Yaoundé, while it was 4.5% in Yaoundé and 12.6% in Dizangué with RDTs. Only abdominal and retro-orbital pains were significantly associated with acute dengue infection. All four dengue serotypes were recorded, with a predominance of DENV-3 (35.45%) and DENV-4 (25.45%). Rapid Diagnostic Tests for either chikungunya or dengue displayed very poor sensitivity. This study further confirms the high endemicity of both dengue and chikungunya in Yaoundé and Dizangué. These data stress the need for active surveillance and the implementation of vector control measures to prevent the occurrence of outbreaks across the country.

Pathogenesis and Manifestations of Zika Virus-Associated Ocular Diseases

Zika virus (ZIKV) is mosquito-borne flavivirus that caused a significant public health concern in French Polynesia and South America. The two major complications that gained the most media attention during the ZIKV outbreak were Guillain-Barré syndrome (GBS) and microcephaly in newborn infants. The two modes of ZIKV transmission are the vector-borne and non-vector borne modes of transmission. Aedes aegypti and Aedes albopictus are the most important vectors of ZIKV. ZIKV binds to surface receptors on permissive cells that support infection and replication, such as neural progenitor cells, dendritic cells, dermal fibroblasts, retinal pigment epithelial cells, endothelial cells, macrophages, epidermal keratinocytes, and trophoblasts to cause infection. The innate immune response to ZIKV infection is mediated by interferons and natural killer cells, whereas the adaptive immune response is mediated by CD8⁺T cells, Th1 cells, and neutralizing antibodies. The non-structural proteins of ZIKV, such as non-structural protein 5, are involved in the evasion of the host's immune defense mechanisms. Ocular manifestations of ZIKV arise from the virus' ability to cross both the blood-brain barrier and blood-retinal barrier, as well as the blood-aqueous barrier. Most notably, this results in the development of GBS, a rare neurological complication in acute ZIKV infection. This can yield ocular symptoms and signs. Additionally, infants to whom ZIKV is transmitted congenitally develop congenital Zika syndrome (CZS). The ocular manifestations are widely variable, and include nonpurulent conjunctivitis, anterior uveitis, keratitis, trabeculitis, congenital glaucoma, microphthalmia, hypoplastic optic disc, and optic nerve pallor. There are currently no FDA approved therapeutic agents for treating ZIKV infections and, as such, a meticulous ocular examination is an important aspect of the diagnosis. This review utilized several published articles regarding the ocular findings of ZIKV, antiviral immune responses to ZIKV infection, and the pathogenesis of ocular manifestations in individuals with ZIKV infection. This review summarizes the current knowledge on the viral immunology of ZIKV, interactions between ZIKV and the host's immune defense mechanism, pathological mechanisms, as well as anterior and posterior segment findings associated with ZIKV infection.

A Comprehensive Update on Retinal Vasculitis: Etiologies, Manifestations and Treatments

Retinal vasculitis is characterized by inflammatory involvement of retinal arterioles, venules and/or capillaries and can be associated with a myriad of systemic and ophthalmic diseases. In this review, we have comprehensively discussed the etiologies, clinical manifestations, and presentations of retinal vasculitis. We have also included newer advances in imaging in retinal vasculitis such as OCTA and widefield imaging.

Cross-tissue and generation predictability of relative Wolbachia densities in the mosquito Aedes aegypti

BACKGROUND

The insect endosymbiotic bacterium Wolbachia is being deployed in field populations of the mosquito Aedes aegypti for biological control. This microbe prevents the replication of human disease-causing viruses inside the vector, including dengue, Zika and chikungunya. Relative Wolbachia densities may in part predict the strength of this 'viral blocking' effect. Additionally, Wolbachia densities may affect the strength of the reproductive manipulations it induces, including cytoplasmic incompatibility (CI), maternal inheritance rates or induced fitness effects in the insect host. High rates of CI and maternal inheritance and low rates of fitness effects are also key to the successful spreading of Wolbachia through vector populations and its successful use in biocontrol. The factors that control Wolbachia densities are not completely understood.

METHODS

We used quantitative PCR-based methods to estimate relative density of the Wolbachia wAlbB strain in both the somatic and reproductive tissues of adult male and female mosquitoes, as well as in eggs. Using correlation analyses, we assessed whether densities in one tissue predict those in others within the same individual, but also across generations.

RESULTS

We found little relationship among the relative Wolbachia densities of different tissues in the same host. The results also show that there was very little relationship between Wolbachia densities in parents and those in offspring, both in the same and different tissues. The one exception was with ovary-egg relationships, where there was a strong positive association. Relative Wolbachia densities in reproductive tissues were always greater than those in the somatic tissues. Additionally, the densities were consistent in females over their lifetime regardless of tissue, whereas they were generally higher and more variable in males, particularly in the testes.

CONCLUSIONS

Our results indicate that either stochastic processes or local tissue-based physiologies are more likely factors dictating Wolbachia densities in Ae. aegypti individuals, rather than shared embryonic environments or heritable genetic effects of the mosquito genome. These findings have implications for understanding how relative Wolbachia densities may evolve and/or be maintained over the long term in Ae. aegypti.

Anterior scleritis treated with systemic corticosteroids in Chikungunya infection

Background

Case report

Conclusion

Ocular Manifestations of Chikungunya Infection: A Systematic Review

The Chikungunya virus (CHIKV) can cause long lasting symptoms and manifestations. However, there is little information on which ocular ones are most frequent following infection. We performed a systematic review (registered in the International Prospective Register of Systematic Reviews; no CRD42020171928) to establish the most frequent ocular manifestations of CHIKV infection and their associations with gender and age. Articles published until September 2020 were selected from PubMed, Scielo, Cochrane and Scopus databases. Only studies with CHIKV-infected patients and eye alterations were included. Reviews, descriptive studies, or those not investigating the human ocular manifestations of CHIKV, those with patients with other diseases and infections, abstracts and studies without relevant data were excluded. Twenty-five studies were selected for inclusion. Their risk of bias was evaluated by a modified Newcastle-Ottawa scale. The most frequent ocular symptoms of CHIKV infection included ocular pain, inflammation and reduced visual acuity, whilst conjunctivitis and optic neuritis were the most common manifestations of the disease. These occurred mostly in individuals of 42 ± 9.5 years of age and woman. The few available reports on CHIKV-induced eye manifestations highlight the need for further research in the field to gather more substantial evidence linking CHIKV infection, the eye and age/gender. Nonetheless, the data emphasizes that ocular alterations are meaningful occurrences of CHIKV infection which can substantially affect quality of life.

Dengue 2 serotype and yellow fever coinfection

Case Presentation

Arboviruses primarily consist of RNA, which favours greater genetic plasticity, with a higher frequency of mutations that allow the virus to adapt to different hosts. The initial symptomatology is nonspecific, in that the patient can present fever, myalgia, arthralgia, rash and headache. This makes a clinical diagnosis using laboratory tests difficult and time-consuming. In Brazil, the main arboviruses involved in epidemics belong to the family Flaviviridae. The patient in this case is from the municipality of São Bernardo do Campo, an area endemic for arboviruses. He presented symptoms of fever, myalgia and headache.

Results

The multiplex assay for arboviruses detected genetic material from the dengue 2 and yellow fever viruses.

Conclusion

This result confirms the importance of molecular tests showing high sensitivity and specificity that can assist clinical diagnosis, particularly in endemic areas during periods of outbreak for other arboviruses, like the epidemiological picture in Brazil in 2018, when significant co-circulation of dengue virus and yellow fever virus occurred. The presence of co-circulating arboviruses increases the chance of coinfection and demonstrates the importance of differential diagnosis.

Increased Retinal Vessel Tortuosity Associated With Crimean-Congo Hemorrhagic Fever in Children

BACKGROUND

To evaluate the ocular symptoms and findings of children diagnosed with Crimean-Congo hemorrhagic fever (CCHF).

METHODS

In this prospective study, children diagnosed with CCHF who underwent a complete ophthalmologic examination during the hospitalization period were included.

RESULTS

Twenty-four children with a mean age of 12.4 ± 3.6 years were included study. The most common ocular finding was conjunctival hyperemia and was observed in 50% of patients. Nine (37.4%) children had abnormalities in fundus examination. Two (8.3%) of them had dilated retinal veins, and 7 (29.1%) had tortuous retinal vessels. No significant difference was found between mild to moderate and severe disease groups in terms of ocular symptoms and ophthalmologic examination findings (P > 0.05, for all).

CONCLUSIONS

The increased retinal vessel tortuosity was detected as a fundus examination finding in children with CCHF. Both ophthalmologists and pediatricians should be aware of the various ocular manifestations of CCHF for rapid diagnosis and management.

Hatching pattern and coexistence of Aedes aegypti and Aedes albopictus (Culicidae) in a subtropical city, Argentina, after three decades of coexistence

Aedes aegypti and Aedes albopictus are mosquito vectors of numerous arboviruses of sanitary importance. Presently in Argentina, neither Ae. aegypti nor Ae. albopictus, have displaced the other species in the places where they coexist, since the introduction of the latter in 1998. In this study, we evaluated whether these species coexist at different scales (ovitrap, microhabitat and habitat) in the city of Eldorado, Misiones province, northeast Argentina. We also analyzed the seasonal variation and climate variables related to the delay in egg hatching of both species. Mosquitoes were collected weekly, from June 2017 to May 2018, using ovitraps placed in urban areas. We conclude that Ae. aegypti and Ae. albopictus coexist in the study area, at the ovitrap, microhabitat and habitat scales. Furthermore, no pronounced pattern of delayed hatching has been observed for either species; however, eggs of Ae. albopictus laid during colder weeks and less rainfall needed a greater number of immersions to hatch, while for Ae. aegypti those laid during weeks with low rainfall and high temperatures showed the longest delay in hatching response.

Povidone-Iodine Attenuates Viral Replication in Ocular Cells: Implications for Ocular Transmission of RNA Viruses

Several RNA viruses, including SARS-CoV-2, can infect or use the eye as an entry portal to cause ocular or systemic diseases. Povidone-Iodine (PVP-I) is routinely used during ocular surgeries and eye banking as a cost-effective disinfectant due to its broad-spectrum antimicrobial activity, including against viruses. However, whether PVP-I can exert antiviral activities in virus-infected cells remains elusive. In this study, using Zika (ZIKV) and Chikungunya (CHIKV) virus infection of human corneal and retinal pigment epithelial cells, we report antiviral mechanisms of PVP-I. Our data showed that PVP-I, even at the lowest concentration (0.01%), drastically reduced viral replication in corneal and retinal cells without causing cellular toxicity. Antiviral effects of PVP-I against ZIKV and CHIKV were mediated by direct viral inactivation, thus attenuating the ability of the virus to infect host cells. Moreover, one-minute PVP-I exposure of infected ocular cells drastically reduced viral replication and the production of infectious progeny virions. Furthermore, viral-induced (CHIKV) expression of inflammatory genes (TNF-α, IL-6, IL-8, and IL1β) were markedly reduced in PVP-I treated corneal epithelial cells. Together, our results demonstrate potent antiviral effects of PVP-I against ZIKV and CHIKV infection of ocular cells. Thus, a low dose of PVP-I can be used during tissue harvesting for corneal transplants to prevent potential transmission of RNA viruses via infected cells.

Ocular manifestations of emerging viral diseases

Emerging infectious diseases (EIDs) are an increasing threat to public health on a global scale. In recent times, the most prominent outbreaks have constituted RNA viruses, spreading via droplets (COVID-19 and Influenza A H1N1), directly between humans (Ebola and Marburg), via arthropod vectors (Dengue, Zika, West Nile, Chikungunya, Crimean Congo) and zoonotically (Lassa fever, Nipah, Rift Valley fever, Hantaviruses). However, specific approved antiviral therapies and vaccine availability are scarce, and public health measures remain critical. Patients can present with a spectrum of ocular manifestations. Emerging infectious diseases should therefore be considered in the differential diagnosis of ocular inflammatory conditions in patients inhabiting or returning from endemic territories, and more general vigilance is advisable in the context of a global pandemic. Eye specialists are in a position to facilitate swift diagnosis, improve clinical outcomes, and contribute to wider public health efforts during outbreaks. This article reviews those emerging viral diseases associated with reports of ocular manifestations and summarizes details pertinent to practicing eye specialists.

Measuring the global burden of chikungunya and Zika viruses: A systematic review

Throughout the last decade, chikungunya virus (CHIKV) and Zika virus (ZIKV) infections have spread globally, causing a spectrum of disease that ranges from self-limited febrile illness to permanent severe disability, congenital anomalies, and early death. Nevertheless, estimates of their aggregate health impact are absent from the literature and are currently omitted from the Global Burden of Disease (GBD) reports. We systematically reviewed published literature and surveillance records to evaluate the global burden caused by CHIKV and ZIKV between 2010 and 2019, to calculate estimates of their disability-adjusted life year (DALY) impact. Extracted data on acute, chronic, and perinatal outcomes were used to create annualized DALY estimates, following techniques outlined in the GBD framework. This study is registered with PROSPERO (CRD42020192502). Of 7,877 studies identified, 916 were screened in detail, and 21 were selected for inclusion. Available data indicate that CHIKV and ZIKV caused the average yearly loss of over 106,000 and 44,000 DALYs, respectively, between 2010 and 2019. Both viruses caused substantially more burden in the Americas than in any other World Health Organization (WHO) region. This unequal distribution is likely due to a combination of limited active surveillance reporting in other regions and the lack of immunity that left the previously unexposed populations of the Americas susceptible to severe outbreaks during the last decade. Long-term rheumatic sequelae provided the largest DALY component for CHIKV, whereas congenital Zika syndrome (CZS) contributed most significantly for ZIKV. Acute symptoms and early mortality accounted for relatively less of the overall burden. Suboptimal reporting and inconsistent diagnostics limit precision when determining arbovirus incidence and frequency of complications. Despite these limitations, it is clear from our assessment that CHIKV and ZIKV represent a significant cause of morbidity that is not included in current disease burden reports. These results suggest that transmission-blocking strategies, including vector control and vaccine development, remain crucial priorities in reducing global disease burden through prevention of potentially devastating arboviral outbreaks.

Chikungunya and Zika are 2 mosquito-borne viral diseases that can cause both acute symptoms and long-term, debilitating complications in infected individuals. Chikungunya is best known as a cause of persistent arthritis in otherwise recovered patients and Zika as a cause of cognitive, motor, and sensory anomalies in newborn children. Both diseases emerged in the Americas within the last decade and have since spread rapidly throughout the region. Despite their widespread transmission there and throughout much of the world, chikungunya and Zika remain neglected diseases. One of the most significant obstacles to address their spread is a lack of data involving their burden. We searched the published literature and surveillance reports to collect information about the incidence, mortality, and morbidity associated with each of these diseases to estimate their regional and global burden during the last decade. Our estimates confirm that chikungunya and Zika caused substantial burden throughout this time frame and place them among the most problematic mosquito-borne viral diseases worldwide. We found that the largest proportion of global burden linked to each disease between 2010 and 2019 occurred in the Americas, although this observation is likely due to limited reporting in other regions.

Manifestaciones Oculares Posterior a Infecciones por Arbovirus

Introducción: Las infecciones por virus del Dengue, Chikungunya y Zika se han asociado a manifestaciones oculares como neurorretinitis, vasculitis, coroiditis, coriorretinitis, obstrucción venosa, edema macular, foveolitis, entre otras. Objetivo: El propósito del estudio es presentar una serie de casos de pacientes con afección ocular causada por infecciones por arbovirus. Metodología: Estudio es de carácter descriptivo, retrospectivo, en formato de reporte de serie de casos, describiendo los hallazgos de manifestaciones oculares secundarias a infecciones de arbovirus. Resultados: Se presentaron 13 pacientes con Dengue, 5 con Chikungunya y 4 con Zika. Doce de sexo masculino y diez femenino, con edades que oscilan entre 18 y 62 años. Conclusión: El Dengue es la infección con mayor recurrencia de manifestaciones oculares. El tratamiento con esteroides y anti-VEGF utilizado en base a la evidencia disponible demostró un impacto positivo en la evolución de la agudeza visual. El tratamiento conservador en pacientes con obstrucción de vena central de retina fue efectivo en aquellos que no presentaron la variante isquémica. La atrofia óptica fue la complicación más frecuente y presentó mejoría una vez el cuadro inflamatorio ha sido resuelto.

[Ocular manifestations of viral diseases]

Les infections virales peuvent toucher l’ensemble des tuniques oculaires et mettre en jeu la fonction visuelle à plus ou moins courte terme. Les kératites et kérato-uvéites liées au virus HSV-1 sont les atteintes les plus fréquentes. Les récurrences entraînent une opacification cornéenne irréversible qui en fait la première cause de cécité d’origine infectieuse dans les pays occidentaux, et justifient un traitement antiviral préventif au long cours. Le zona ophtalmique (10 à 20 % des zonas), peut s’accompagner d’atteintes oculaires sévères (kératites, kérato-uvéites), dont 30 % deviennent chroniques/récurrentes, et de douleurs post-zostériennes, redoutables dans le territoire trigéminé. Les rétinites nécrosantes liées aux herpesvirus (HSV, VZV, CMV), sont rares mais constituent des urgences fonctionnelles absolues nécessitant un traitement antiviral par voie intraveineuse et intravitréenne. Les conjonctivites à adénovirus constituent la première cause de conjonctivite infectieuse. Le plus souvent bénignes, elles sont extrêmement contagieuses et peuvent se compliquer de lésions cornéennes invalidantes persistant plusieurs mois, voire années. Certaines arboviroses s’accompagnent de manifestations oculaires inflammatoires. Dans le cas du Zika, les infections congénitales peuvent se compliquer d’atrophie maculaire et/ou optique. Les conjonctivites sont très fréquentes à la phase aiguë de la maladie à virus Ebola, dont 15 % des survivants présentent des atteintes inflammatoires chroniques sévères liées à la persistance du virus dans les tissus uvéaux. Enfin, dans le cadre de la COVID-19, les conjonctivites ne sont pas très fréquentes mais peuvent être inaugurales, voire au premier plan et sont associées à une excrétion virale lacrymale qui doit faire prendre toutes les précautions.

Ocular Manifestations of West Nile Virus

Ocular manifestations are a feature of West Nile virus infection. They mostly occur in association with severe neuroinvasive disease. Linear chorioretinitis is suggestive of the diagnosis and may raise diagnostic suspicion when associated with evocative systemic signs, and in an epidemic context. Various other less specific inflammatory ocular manifestations have been reported, including anterior uveitis, occlusive retinal vasculitis, optic neuritis, and diplopia. The pathophysiology of ocular disease remains unclear, but it reflects the neuroinvasiveness of the disease. Although ocular involvement most often resolves without visual sequelae, some patients may have permanent loss of vision, adding to the need for the development of a specific treatment and/or vaccines.

The effects of regional climatic condition on the spread of COVID-19 at global scale

The pandemic outbreak of the novel coronavirus epidemic disease (COVID-19) is spreading like a diffusion-reaction in the world and almost 208 countries and territories are being affected around the globe. It became a sever health and socio-economic problem, while the world has no vaccine to combat this virus. This research aims to analyze the connection between the fast spread of COVID-19 and regional climate parameters over a global scale. In this research, we collected the data of COVID-19 cases from the time of 1st reported case to the 5th June 2020 in different affected countries and regional climatic parameters data from January 2020 to 5th June 2020. It was found that most of the countries located in the relatively lower temperature region show a rapid increase in the COVID-19 cases than the countries locating in the warmer climatic regions despite their better socio-economic conditions. A correlation between metrological parameters and COVID-19 cases was observed. Average daylight hours are correlated to total the COVID-19 cases with a coefficient of determination of 0.42, while average high-temperature shows a correlation of 0.59 and 0.42 with total COVID-19 cases and death cases respectively. The finding of the study will help international health organizations and local administrations to combat and well manage the spread of COVID-19.

Neurocognitive impacts of arbovirus infections

Arthropod-borne viruses or arbovirus, are most commonly associated with acute infections, resulting on various symptoms ranging from mild fever to more severe disorders such as hemorrhagic fever. Moreover, some arboviral infections can be associated with important neuroinflammation that can trigger neurological disorders including encephalitis, paralysis, ophthalmological impairments, or developmental defects, which in some cases, can lead to long-term defects of the central nervous system (CNS). This is well illustrated in Zika virus-associated congenital brain malformations but also in West Nile virus-induced synaptic dysfunctions that can last well beyond infection and lead to cognitive deficits. Here, we summarize clinical and mechanistic data reporting on cognitive disturbances triggered by arboviral infections, which may highlight growing public health issues spanning the five continents.

Immunopathogenesis of alphaviruses

Alphaviruses, members of the enveloped, positive-sense, single-stranded RNA Togaviridae family, represent a reemerging public health threat as mosquito vectors expand into new geographic territories. The Old World alphaviruses, which include chikungunya virus, Ross River virus, and Sindbis virus, tend to cause a clinical syndrome characterized by fever, rash, and arthritis, whereas the New World alphaviruses, which consist of Venezuelan equine encephalitis virus, eastern equine encephalitis virus, and western equine encephalitis virus, induce encephalomyelitis. Following recovery from the acute phase of infection, many patients are left with debilitating persistent joint and neurological complications that can last for years. Clues from human cases and studies using animal models strongly suggest that much of the disease and pathology induced by alphavirus infection, particularly atypical and chronic manifestations, is mediated by the immune system rather than directly by the virus. This review discusses the current understanding of the immunopathogenesis of the arthritogenic and neurotropic alphaviruses accumulated through both natural infection of humans and experimental infection of animals, particularly mice. As treatment following alphavirus infection is currently limited to supportive care, understanding the contribution of the immune system to the disease process is critical to developing safe and effective therapies.

An unusual case of unilateral chorioretinitis and blind spot enlargement associated with asymptomatic West Nile virus infection

PURPOSE

To report a case of unilateral chorioretinitis and acute blind spot enlargement occurring in a patient with asymptomatic West Nile virus (WNV) infection.

OBSERVATIONS

A 28-year-old Hispanic woman, residing in Puerto Rico, presented with an 18-month history of photopsia and a visual field disturbance of the left eye. She had no history of other neurologic symptoms or viral-like illness concurrent with the onset of her symptoms. Corrected visual acuity was 20/20 on both eyes. The left fundus revealed multifocal chorioretinitis, at different stages of evolution, several creamy orange lesions on the mid-periphery along with multiple small punched out lesions, some of which were following a curvilinear pattern distribution. Visual field testing revealed physiological blind spot enlargement on the left eye. Serum WNV antibody serology revealed negative IgM (<0.90) and positive IgG (1.58, <1.30 reference). The patient was treated with oral prednisone, 60mg for two weeks, followed by a 13-week taper of therapy, which resulted in normalization of the visual field defect.

CONCLUSION AND IMPORTANCE

Our case raises the possibility that ophthalmic manifestations may occur in some patients with asymptomatic WNV infection. It also suggests that acute blind spot enlargement may also be part of the myriad of ophthalmic manifestations present in WNV patients. In such instances where acute blind spot enlargement is present, oral prednisone may result in improvement and subsequent normalization of the visual field defect. Besides, our case provides evidence to suggest that primary WNV transmission is possible in Puerto Rico.

Study of Usutu virus neuropathogenicity in mice and human cellular models

Usutu virus (USUV), an African mosquito-borne flavivirus closely related to West Nile virus, was first isolated in South Africa in 1959. USUV emerged in Europe two decades ago, causing notably massive mortality in Eurasian blackbirds. USUV is attracting increasing attention due to its potential for emergence and its rapid spread in Europe in recent years. Although mainly asymptomatic or responsible for mild clinical signs, USUV was recently described as being associated with neurological disorders in humans such as encephalitis and meningoencephalitis, highlighting the potential health threat posed by the virus. Despite this, USUV pathogenesis remains largely unexplored. The aim of this study was to evaluate USUV neuropathogenicity using in vivo and in vitro approaches. Our results indicate that USUV efficiently replicates in the murine central nervous system. Replication in the spinal cord and brain is associated with recruitment of inflammatory cells and the release of inflammatory molecules as well as induction of antiviral-responses without major modulation of blood-brain barrier integrity. Endothelial cells integrity is also maintained in a human model of the blood-brain barrier despite USUV replication and release of pro-inflammatory cytokines. Furthermore, USUV-inoculated mice developed major ocular defects associated with inflammation. Moreover, USUV efficiently replicates in human retinal pigment epithelium. Our results will help to better characterize the physiopathology related to USUV infection in order to anticipate the potential threat of USUV emergence.

Number of emerging arboviruses involved in human infections has increased considerably in the past years. Among them, Usutu virus (USUV) is an African mosquito-borne virus first isolated in South Africa that recently emerged. USUV infection in humans is considered to be most often asymptomatic or to cause mild clinical signs. Nonetheless, increased cases of neurological complications such as encephalitis or meningoencephalitis have been reported in Europe but the mechanisms behind this neuropathogenesis remain largely unclear. In this study we showed that USUV can infect efficiently several organs and cells of the central nervous system associated with a drastic inflammation and various deleterious effects. Our results contribute to the characterization of the neurotropism related to USUV infection.

Arboviruses (chikungunya, dengue, and Zika) associated with ophthalmic changes: a focus on aqueous fluid and vitreous humor

The aim of this study was to conduct a bibliographic survey and correlates the presence of arboviroses in the eyeball with the main eye changes presented by the population under study. This study is a systematic review of journals and indexed articles, carried out between January 2019 and June 2019, in which there was a query in the Pubmed/Medline and Scielo databases without temporal restriction. In addition to the aforementioned databases, the Brazilian Association of Organ Transplantation Association database, which provides epidemiological data on organ and tissue transplants in Brazil, was used as a research source. The Midwest region contributed to the increase in the number of organ transplants in Brazil. The number of corneal transplants in Brazil surpassed the number of organ transplants by four times. Several ophthalmic changes associated with Chikungunya, Dengue, and Zika virus infections have been diagnosed; however, few studies have identified the presence of the virus in the eyeball. Arboviruses are of great relevance to public health due to a number of factors, ranging from the diversity of infectious agents involved and the plurality of clinical manifestations because the absence of efficient laboratory support, leading to delayed disease confirmation due to lack of differential diagnostics available. Added to these difficulties is the lack of specific therapy, leaving only the symptomatic control of clinical manifestations as the only treatment option. However, the manifestations are directly associated with the decreased quality of vision and consequently the quality of life of patients.

Characterization of Retinopathy Among Patients With Yellow Fever During 2 Outbreaks in Southeastern Brazil

Importance

Yellow fever still threatens people in endemic areas, and besides conjunctival icterus, little is known about the ocular changes that occur in these patients.

Objective

To characterize retinal changes in patients with confirmed yellow fever during 2 recent outbreaks of the disease in Minas Gerais, Southeastern Brazil.

Design, Setting, and Participants

This cross-sectional, observational study conducted at a single referral center for infectious diseases in Southeastern Brazil collected data between January 2017 and February 2018 from 94 consecutive patients with suspicion of yellow fever who were eligible for the study.

Main Outcomes and Measures

Patients underwent ophthalmic examination. Clinical findings, laboratory results, and occurrence of retinopathy and death during hospitalization were reported, including age, sex, comorbidities, disease severity, serum aspartate aminotransferase level, total bilirubin level, serum creatinine level, arterial lactate level, international normalized ratio, and platelet count at hospital admission.

Results

In total, 64 patients were included who had received a confirmed diagnosis of yellow fever, with a median (interquartile range) age of 47 (38-56) years, and 12 patients (19%) were women. Twenty eyes (16%) of 13 patients (20%) had retinopathy at the same time as yellow fever. The most common fundus changes among the 20 eyes were retinal nerve fiber layer infarcts (11 [55%]), superficial hemorrhages (7 [35%]) and grayish deep lesions (6 [30%]), possibly at the level of the outer retina or choroid. Aspartate aminotransferase levels higher than 3000 U/L (odds ratio [OR], 14.2; 95% CI, 3.5-77.8; P < .001), total bilirubin levels higher than 2.3 mg/dL (OR, 20.0; 95% CI, 4.4-159.7; P < .001), serum creatinine levels higher than 2.0 mg/dL (OR, 8.2; 95% CI, 2.1-36.0; P = .003), arterial lactate levels higher than 17.1/mg/dL (OR, 4.6; 95% CI, 1.1-19.0; P = .03), platelet count lower than 94 × 103/μL (OR, 7.8; 95% CI, 1.8-59.9; P = .004), and classification of disease as severe (OR, 11.7; 95% CI, 2.0-301.0; P = .003) were associated with retinopathy. Arterial hypertension, diabetes, international normalized ratio, and death were not associated with retinopathy.

Conclusions and Relevance

Retinopathy was present in 20% of patients with yellow fever and appeared to be associated with more severe systemic disease. Retinal nerve fiber layer infarcts and superficial hemorrhages, but not the grayish deep lesions, resembled those associated with other flavivirus (eg, dengue virus) infections. The clinical relevance of these findings may warrant further investigation.

A new immunoassay of hybrid nanomater conjugated to aptamers for the detection of dengue virus

A new immunosensor using hybrid nanomaterials for the detection of dengue virus was demonstrated in this work. This immunosensor composed of nanoparticles of γ-Fe₂O₃(SAMN) modified with MPA- SAMN@MPA was characterized by FTIR spectroscopy, transmission electron microscopy,quartz crystal microbalance, UV-vis and LSPR technique. The binding of SAMN@MPA with AuNPs conjugated with aptamers(SAMN@MPA@AuNPs@aptamer) provides specific chemical bonds to four dengue serotypes. Colorimetric changes in the modification steps provided rapid visual detection of the virus without the use of equipment. Variations of aptamers concentrations 1.0-10.0 μM where the 3.0 μM aptamer concentration is sufficient to completely cover the surface of the modified AuNPs with an R² value of> 0.99. This new proposed methodology presenting some advantages in relation to traditional detection methods such as time optimization and cost,can be used as a diagnostic method.

Zika virus induces strong inflammatory responses and impairs homeostasis and function of the human retinal pigment epithelium

BACKGROUND

Zika virus (ZIKV) has recently re-emerged as a pathogenic agent with epidemic capacities as was well illustrated in South America. Because of the extent of this health crisis, a number of more serious symptoms have become associated with ZIKV infection than what was initially described. In particular, neuronal and ocular disorders have been characterized, both in infants and in adults. Notably, the macula and the retina can be strongly affected by ZIKV, possibly by a direct effect of the virus. This is supported by the detection of replicative and infectious virus in lachrimal fluid in human patients and mouse models.

METHODS

Here, we used an innovative, state-of-the-art iPSC-derived human retinal pigment epithelium (RPE) model to study ZIKV retinal impairment.

FINDINGS

We showed that the human RPE is highly susceptible to ZIKV infection and that a ZIKV African strain was more virulent and led to a more potent epithelium disruption and stronger anti-viral response than an Asian strain, suggesting lineage differences. Moreover, ZIKV infection led to impaired membrane dynamics involved in endocytosis, organelle biogenesis and potentially secretion, key mechanisms of RPE homeostasis and function.

INTERPRETATION

Taken together, our results suggest that ZIKV has a highly efficient ocular tropism, which creates a strong inflammatory environment that could have acute or chronic adverse effects. FUND: This work was funded by Retina France, REACTing and La Région Languedoc-Roussillon.

Ocular Manifestations of Emerging Flaviviruses and the Blood-Retinal Barrier

Despite flaviviruses remaining the leading cause of systemic human infections worldwide, ocular manifestations of these mosquito-transmitted viruses are considered relatively uncommon in part due to under-reporting. However, recent outbreaks of Zika virus (ZIKV) implicated in causing multiple ocular abnormalities, such as conjunctivitis, retinal hemorrhages, chorioretinal atrophy, posterior uveitis, optic neuritis, and maculopathies, has rejuvenated a significant interest in understanding the pathogenesis of flaviviruses, including ZIKV, in the eye. In this review, first, we summarize the current knowledge of the major flaviviruses (Dengue, West Nile, Yellow Fever, and Japanese Encephalitis) reported to cause ocular manifestations in humans with emphasis on recent ZIKV outbreaks. Second, being an immune privilege organ, the eye is protected from systemic infections by the presence of blood-retinal barriers (BRB). Hence, we discuss how flaviviruses modulate retinal innate response and breach the protective BRB to cause ocular or retinal pathology. Finally, we describe recently identified infection signatures of ZIKV and discuss whether these system biology-predicted genes or signaling pathways (e.g., cellular metabolism) could contribute to the pathogenesis of ocular manifestations and assist in the development of ocular antiviral therapies against ZIKV and other flaviviruses.