Conjunctiva is not a preferred gateway of entry for SARS-CoV-2 to infect respiratory tract

The Latest Cellular and Molecular Mechanisms of COVID-19 on Non-Lung Organs

Understanding the transmission pathways of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) will aid in developing effective therapies directed at the virus’s life cycle or its side effects. While severe respiratory distress is the most common symptom of a coronavirus 2019 (COVID-19) infection, the virus is also known to cause damage to almost every major organ and system in the body. However, it is not obvious whether pathological changes in extra-respiratory organs are caused by direct infection, indirect, or combination of these effects. In this narrative review, we first elaborate on the characteristics of SARS-CoV-2, followed by the mechanisms of this virus on various organs such as brain, eye, and olfactory nerve and different systems such as the endocrine and gastrointestinal systems.

Presence of SARS-CoV-2 on the conjunctival mucosa in patients hospitalized due to COVID-19: Pathophysiological considerations and therapeutic implications

Introduction

Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) resulted in a worldwide pandemic, due to its great capacity to invade the human body. Previous studies have shown that the primary route of invasion of this virus is the human respiratory tract via the co-expression of ACE2 receptor and TMPRSS2, a serine protease on the cellular surface. Interestingly, this condition is present not only on the respiratory epithelium but on the conjunctival mucosa, as well. Thus, we hypothesized that SARS-CoV-2 is present on the conjunctival mucosa.

Aim

To prove that SARS-CoV-2 can be detected in the conjunctiva.

Methods

Previously nasopharyngeal swab-sample based real-time polymerase chain reaction (PCR) positive COVID-19 infected patients were selected at the COVID Care Centers of Semmelweis University, Budapest, Hungary. The study was approved by the ethical committee of Semmelweis University. During their recovery, both nasopharyngeal and conjunctival swab-samples were taken and PCR method was used to detect the presence of SARS-CoV-2 RNA. Appropriate statistical analysis was performed.

Results

The study population consisted of 97 patients, 49 females (50.5%) and 48 males (49.5%), with a mean age of 67.2 ± 11.9 years. During recovery, with nasopharyngeal swabs, the PCR test was positive in 55 cases (56.70%), whereas with conjunctival swabs it was positive in 8 cases (8.25%). Both tests were positive in 5 cases (5.15%). In some patients, ocular symptoms were observed as well. The rest of the patients (29 cases) had negative nasopharyngeal PCR tests during recovery.

Conclusions

Although only in few cases, the data of the present study provides a proof of concept that SARS-CoV-2 can be present on the conjunctival mucosa even in nasopharyngeal negative patients, a finding, which can have clinical importance. Also, on the basis of these findings one can hypothesize that - in addition to the respiratory tract – the conjunctiva can be an entrance route for SARS-CoV-2 to the human body. Thus, in high-risk conditions, in addition to covering the mouth and nose with mask, the protection of the eyes is also strongly recommended.

Updates on Coronavirus-Related Ocular Manifestations: From the Past to COVID-19 Pandemic

Context: Coronaviruses are the largest RNA viruses associated with some ocular manifestations. There are various contradictory reports about the ocular manifestations of coronaviruses in humans. Different ocular tissues can affect coronavirus-associated infectious diseases. Evidence Acquisition: All manuscripts were collected from PubMed, Google Scholar, and other relevant databases. All searches were done by specific keywords, including "coronavirus," "ocular disease," and "eye." Results: There are various contradictory reports about the ocular effects of coronaviruses in humans. Different ocular tissues are involved in coronavirus-associated infectious diseases. The ductal connection between the upper respiratory tract and eye mucosa through the nasolacrimal duct can be an entrance to respiratory viruses, such as coronaviruses. The coronavirus can infect the retina, conjunctiva, cornea, and uvea of the eye. The primary SARS-CoV-2 receptor, ACE2, is mainly expressed in the posterior tissues of the eye, such as the retina and RPE. Feline CoV, SARS-CoV, MERS-CoV, and infectious bronchitis virus (IBV) are responsible for conjunctiva involvement in coronavirus-related ocular pathogenesis. Also, various studies are held on COVID-19 and the impact of the conjunctiva on diagnosis and medical complications. Given that the cornea has an acceptable expression of ACE2 and TMPRSS2 genes compared to lung tissue, some studies were done on the impact of the cornea in COVID-19. Feline infectious peritonitis virus (FIPV) is also related to uvea complications. The experiments of human and animal models on the effects of coronaviruses on the retina and cornea in the event of various epidemics of coronaviruses and new and unknown ocular complications can be of great help to future studies. Conclusions: Given the importance of investigating the pathogenesis and other routes of SARS-CoV-2 infection, especially in areas other than the respiratory tract, this report attempts to highlight the importance of eye infections caused by the virus, its role in maintaining the virus transmission chain, and its impact on public health.

Redefining aerosol in dentistry during COVID-19 pandemic

The corona virus malady 2019 (COVID-19) pandemic has rekindled the well established argument regarding the role of dental aerosol in transference of severe acute respiratory syndrome corona virus 2 (SARS-CoV-2). Aerosols and droplets are generated amid innumerable dental procedures. With the commencement of the COVID-19 pandemic droplet, a review of the infection/disease control strategies for aerosols is required. We do not know where this pandemic is directed. We do not have conclusive evidence for an optimal management strategy. Every day brings in varying information, so recognizing the hazard created by aerosols will help diminish the probability of infection transfer at the time of dental procedures. Hence, the author assessed the evidence-based medical and dental literature in relation to "aerosol' that documented the source of transmission of aerosol through various potential routes, addressed the risk potential to patients and the dental team, and assessed the additional measures that might minimize the viral transmission if regularly adopted. In this article, the author evaluated and compiled dental guidelines by various countries and various health-care associations in context to aerosol-generating procedures and has made recommendations for the restriction of dental aerosols and splatter in routine dental practice.

Photonics enabled intelligence system to identify SARS-CoV 2 mutations

Abstract

The COVID-19, MERS-CoV, and SARS-CoV are hazardous epidemics that have resulted in many deaths which caused a worldwide debate. Despite control efforts, SARS-CoV-2 continues to spread, and the fast spread of this highly infectious illness has posed a grave threat to global health. The effect of the SARS-CoV-2 mutation, on the other hand, has been characterized by worrying variations that modify viral characteristics in response to the changing resistance profile of the human population. The repeated transmission of virus mutation indicates that epidemics are likely to occur. Therefore, an early identification system of ongoing mutations of SARS-CoV-2 will provide essential insights for planning and avoiding future outbreaks. This article discussed the following highlights: First, comparing the omicron mutation with other variants; second, analysis and evaluation of the spread rate of the SARS-CoV 2 variations in the countries; third, identification of mutation areas in spike protein; and fourth, it discussed the photonics approaches enabled with artificial intelligence. Therefore, our goal is to identify the SARS-CoV 2 virus directly without the need for sample preparation or molecular amplification procedures. Furthermore, by connecting through the optical network, the COVID-19 test becomes a component of the Internet of healthcare things to improve precision, service efficiency, and flexibility and provide greater availability for the evaluation of the general population.

Key points

• A proposed framework of photonics based on AI for identifying and sorting SARS-CoV 2 mutations.

• Comparative scatter rates Omicron variant and other SARS-CoV 2 variations per country.

• Evaluating mutation areas in spike protein and AI enabled by photonic technologies for SARS-CoV 2 virus detection.

Ocular Distribution of the Renin-Angiotensin-Aldosterone System in the Context of the SARS-CoV-2 Pandemic

The COVID-19 pandemic has resulted in an unprecedented impact on global health, economy, and way of life. SARS-CoV-2, the virus responsible for the disease, utilizes the ACE2 receptor found on host cells to mediate entry, replication, and infection. Numerous studies have elucidated the presence of many components of the renin-angiotensin-aldosterone system (RAAS) in the eye, including the ACE2 receptor. Considering this, and the anatomical vulnerability that the exposed ocular surface offers with its interconnectedness to the respiratory system, there is a theoretical risk of pathogen entry from the ocular route as well as the development of COVID-19-associated eye disease. Despite this, the actual epidemiological data demonstrates low ocular symptoms, possibly due to differing ACE2 receptor expression across age, ethnicity, and sex coupled with the protective properties of tears. We summarize the current literature on ocular RAAS with specific focus on the ACE2 receptor and its interplay with the SARS-CoV-2 virus.

RT-PCR Testing of Organ Culture Medium for Corneal Storage Fails to Detect SARS-CoV-2 Infection Due to Lack of Viral Replication

Concerns of possible transmission of SARS-CoV-2 from donors to patients by corneal transplantation have caused a decline in corneal transplantations. Graft culture media are routinely tested for infectious risks, but it is unclear whether this constitutes a viable means to avoid transmitting SARS-CoV-2 via keratoplasty. We found that SARS-CoV-2 RNA was not present in the medium after seven days of organ culture of corneas from donors (n = 4), who were SARS-CoV-2-positive upon tissue procurement. These medium samples showed no presence of viral RNA. To pursue this question under controlled conditions and further exclude the possibility of productive infection in corneal grafts, we inoculated corneoscleral discs from healthy donors (n = 8) with infectious SARS-CoV-2 and performed PCR testing of the culture medium at various time points. After seven days of culture, we also tested for SARS-CoV-2 RNA within the inoculated corneal tissue. The medium from tissue samples inoculated with SARS-CoV-2 showed no increase in viral RNA, which may indicate lack of viral replication in these corneal grafts. SARS-CoV-2-RNA was, however, detected on or in corneal tissue seven days after inoculation. Our data suggest that corneal grafts may not be permissive for replication of SARS-CoV-2 and demonstrates that PCR testing of culture media cannot safely exclude that tissue has been exposed to SARS-CoV-2. It also demonstrates the difficulty to differentiate between virus adherence and virus replication by PCR testing in SARS-CoV-2 exposed tissue.

Evidence-based of conjunctival COVID-19 positivity: An Italian experience: Gemelli Against COVID Group

BACKGROUND

The possible transmission of severe acute respiratory coronavirus 2 (SARS-CoV-2) by tears and conjunctiva is still debated.

METHODS

Main outcome was to investigate the agreement between nasopharyngeal swab (NPs) and conjunctival swabs (Cs) in patients with SARS-CoV-2 infection. We divided patients into four groups: (1) NPs and Cs both negative (C-NF-), (2) NPs positive and Cs negative (NFs+Cs-), (3) NPs negative and Cs positive (NFs-Cs+), and (4) NPs and Cs both positive (NFs-Cs+). The secondary outcomes were to correlate Cs results with systemic clinical parameters such as: oxygen saturation (SpO2), dyspnea degree (DP), radiologic pulmonary impairment based on chest radiography (XR) or computed tomography (CT), blood chemistry as D-Dimer (D-Dimer), fibrinogen, ferritin, lactate dehydrogenase (LDH), and C-reactive protein (C-RP).

RESULTS

A total of 100 conjunctival swabs in 50 patients with SARS-CoV-2 have been enrolled in this interventional clinical trials. Ocular signs (conjunctivitis) were present in five patients (10%). NPs and Cs highlighted a poor level of agreement (0.025; p = 0.404). Median SpO2 levels are the highest in the NF-C- group (98%) and the lowest (90%) in the group NF+C+ (p = 0.001). Pulmonary impairment was statistically significantly different between NFs and Cs groups (p = 0.019). Pulmonary impairment score increased from NFs-Cs- group (3.8 ± 3.9), to NFs+Cs+ group (6.7 ± 4.1). Intensive care unit patients showed higher COVID-19 Cs positivity in conjunctiva (12.5%) against hospitalized ones (5.8%).

CONCLUSIONS

In patients hospitalized for SARS-CoV-2 the virus can be detected in conjunctival swab. Intensive care unit patients may reveal a higher COVID-19 presence in the conjunctiva. The most severe pulmonary impairment can be observed in NFs and Cs positivity.

TRIAL REGISTRATION

Clinicaltrials.gov registration.

ETHICAL COMMITTEE AUTHORIZATION

ID number: 0013008/20.

In-Depth Investigation of Conjunctival Swabs and Tear Fluid of Symptomatic COVID-19 Patients, an Observational Cohort Study

Purpose

The putative presence of SARS-CoV-2 in ocular specimen puts healthcare workers at risk. We thoroughly examined conjunctival swabs and tear fluid in a large cohort of COVID-19 patients.

Methods

A total of 243 symptomatic laboratory-confirmed COVID-19 patients were included in this observational multicenter study. Conjunctival swabs were analyzed by reverse transcription polymerase chain reaction for detection of SARS-CoV-2 RNA. Next-generation sequencing and phylogenetic analysis were performed to identify viral strains and to determine tissue tropism. Schirmer tear samples from 43 hospitalized COVID-19 patients and 25 healthy controls were analyzed by multiplex cytokine immunoassays.

Results

Viral SARS-CoV-2 RNA was detected in conjunctival swabs from 17 (7.0%) of 243 COVID-19 patients. Conjunctival samples were positive for viral SARS-CoV-2 RNA as long as 12 days after disease onset. Cycle threshold (Ct) values for conjunctival swabs (mean 34.5 ± 5.1) were significantly higher than nasopharyngeal swabs (mean 16.7 ± 3.6). No correlation between Ct values of conjunctival and nasopharyngeal swabs was observed. The majority of positive conjunctival samples were detected only once and primarily during the first visit. Next-generation sequencing analysis revealed that the virus strain found in the conjunctiva was most often identical to the one found in the nasopharynx. Tear cytokine levels IL-1β and IL-6 were elevated in COVID-19 patients compared to healthy controls.

Conclusions

Conjunctival samples that were positive for SARS-CoV-2 RNA contained the same viral strain as the nasopharynx.

Translational Relevance

The presence of SARS-CoV-2 viral RNA and elevated cytokines in tear fluid confirm the involvement of the ocular surface in COVID-19 disease.

SARS-CoV-2 on Ocular Surfaces in a Cohort of Patients With COVID-19 From the Lombardy Region, Italy

Importance

Since February 2020, coronavirus disease 2019 (COVID-19) has spread rapidly all over the world, with an epidemiological cluster in Lombardy, Italy. The viral communicability may be mediated by various body fluids, but insufficient information is available on the presence of the virus in human tears.

Objectives

To investigate the rate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in tears collected from patients with COVID-19 by means of real-time reverse transcriptase-polymerase chain reaction (rRT-PCR) assay and to assess the association of virus presence with concomitant clinical conditions.

Design, Setting, and Participants

Cross-sectional study conducted between April 9 and May 5, 2020. The setting was intensive care units at Azienda Socio-Sanitaria Territoriale (ASST) Sette-Laghi Hospital, University of Insubria, in Varese, Lombardy, Italy. A conjunctival swab was performed in 91 patients hospitalized for COVID-19, which was clinically diagnosed by rRT-PCR assay on nasopharyngeal swabs and by radiological imaging. Conjunctival swabs from 17 additional healthy volunteer participants with no symptoms of COVID-19 were examined to evaluate the availability and applicability of the conjunctival swab test.

Exposure

SARS-CoV-2 detection by means of rRT-PCR assay performed on the collected samples obtained by conjunctival swabs.

Main Outcomes and Measures

Conjunctival swab and nasopharyngeal swab results are reported, as well as demographic and clinical data.

Results

A total of 108 participants (mean [SD] age, 58.7 [14.2] years; 55 female and 53 male) were tested for SARS-CoV-2 using rRT-PCR assay, including 91 patients hospitalized with COVID-19 and 17 were healthy volunteers. SARS-CoV-2 was found on the ocular surface in 52 of 91 patients with COVID-19 (57.1%; 95% CI, 46.3%-67.5%), with a wide variability in the mean viral load from both eyes. Among a subset of 41 patients, concordance of 63.0% (95% CI, 41.0%-81.0%) was found between positive conjunctival and nasopharyngeal swab test results when performed within 2 days of each other. In 17 of these patients, nasopharyngeal swab results were negative for SARS-CoV-2. In 10 of these 17 patients, conjunctival swab results were positive for the virus.

Conclusions and Relevance

In this study, SARS-CoV-2 RNA was found on the ocular surface in a large part of this cohort of patients with COVID-19, although the infectivity of this material could not be determined. Because patients may have positive test results with a conjunctival swab and negative results with a nasopharyngeal swab, use of the slightly invasive conjunctival swab may be considered as a supplementary diagnostic test.

[COVID-19: is transmission through eye contact possible?]

The article reviews international and Russian scientific papers concerning the possibility of transmitting coronavirus infections, particularly the COVID-19, through eye surface. According to the studied literature, the incidence of ocular symptoms in COVID-19 is around 0.8-31.6%, with conjunctivitis being the most frequent manifestation. The review summarizes data on virus detection in conjunctival discharge of COVID-19 patients. Across six studies, the total number of patients is 252, among which were 8 cases (3.17%) of virus detection in the conjunctival cavity. The review discusses the reasons for infrequent detection of the virus in the lacrimal fluid. The analyzed data shows that COVID-19 associated conjunctivitis can be the first symptom, the primary manifestation, or sometimes be detected in the lacrimal fluid of patients without any concomitant signs of eye surface inflammation. The article also presents two clinical cases of patients with keratoconjunctivitis and conjunctivitis associated with COVID-19, as well as the results of experimental transconjunctival and respiratory exposure of Rhesus macaques to SARS-CoV-2 with conclusion of possibility of this type of transmission. Additionally, the review contains the opinion of researchers concerning the influence of several factors on the possibility of virus detection in the lacrimal fluid. The conclusion was made that there is possibility of COVID-19 transmission through the eye surface. While it is not being considered a major transmission route, it should not be ignored. Conjunctival cavity of COVID-19 patients can be the source of infection. Eye protection measures should be undertaken when working with potentially infected patients.

Angiotensin-Converting Enzyme 2 (ACE2) in the Context of Respiratory Diseases and Its Importance in Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection

Angiotensin-Converting Enzyme 2 (ACE2) is an 805 amino acid protein encoded by the ACE2 gene expressed in various human cells, especially in those located in the epithelia. The primary function of ACE2 is to produce angiotensin (1–7) from angiotensin II (Ang II). The current research has described the importance of ACE2 and Ang (1–7) in alternative routes of the renin-angiotensin system (RAS) that promote the downregulation of fibrosis, inflammation, and oxidative stress processes in a great variety of diseases, such as hypertension, acute lung injury, liver cirrhosis, and kidney abnormalities. Investigations into the recent outbreak of the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have revealed the importance of ACE2 during infection and its role in recognizing viral binding proteins through interactions with specific amino acids of this enzyme. Additionally, the ACE2 expression in several organs has allowed us to understand the clinical picture related to the infection caused by SARS-CoV-2. This review aims to provide context for the functions and importance of ACE2 with regards to SARS-CoV-2 in the general clinical aspect and its impact on other diseases, especially respiratory diseases.

Keep Eyes on COVID-19: Ophthalmic Symptoms and Potential Transmission of SARS-CoV-2 through the Oculus

In December 2019, a new coronavirus disease 2019 (COVID-19) emerged and rapidly spread globally, posing a worldwide health emergency. The pathogen causing this pandemic was identified as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). It is well known that SARS-CoV-2 transmits via respiratory droplets and close contact with infected individuals or contaminated items. In addition to these two major transmission routes, other modes of transmission have not been confirmed. Considering that some COVID-19 patients have presented with ocular discomforts and positive SARS-CoV-2 RNA in ocular surfaces, as well as the discovery of the SARS-CoV-2 receptors, angiotensin-converting enzyme 2, and transmembrane protease, serine 2, in the oculus, the ocular surface is now thought to be a possible alternative route of SARS-CoV-2 transmission and a replication site. This review summarizes the evidence connecting COVID-19 with ocular tissues, ocular symptoms during SARS-CoV-2 infection, the potential role of the conjunctiva in SARS-CoV-2 transmission, and the physiopathological mechanisms. Appropriate precautions in ophthalmology departments, including innovative complete and effective patient management plans, protective personal equipment, hand hygiene, and strict personal distance intervals, are essential to effectively minimize the spread of SARS-CoV-2 and control the pandemic.

Ocular Involvement of SARS-CoV-2 in a Polish Cohort of COVID-19-Positive Patients

The coronavirus SARS-CoV-2 responsible for the current human COVID-19 pandemic has shown tropism toward different organs with variable efficiency, eyes included. The purpose of this study has been to investigate the presence of detectable SARS-CoV-2 infection in ocular swabs in patients affected by COVID-19. A consecutive series of 74 COVID-19-positive patients (age 21-89) were enrolled at two Polish COVID-19 hospitals for 4 months and were characterized by PCR for the presence of the SARS-CoV-2 genetic material in nasopharyngeal (NP) and ocular swabs, while their respiratory and ocular symptoms were noted. Almost 50% of them presented with severe/critical respiratory involvement, and some degree of eye disease. No tight correlation was observed between the presence of ocular and respiratory symptoms. Three male patients presenting with severe/critical lung disease tested positive in ocular swab, however with mild/moderate ocular symptoms. In conclusion, our study lends further support to the view that overt ocular infection by the SARS-CoV-2 virus is not such a frequent occurrence.

Eyes on coronavirus

Recently, coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 has spread around the world and is receiving worldwide attention. Approximately 20% of infected patients are suffering from severe disease of multiple systems and in danger of death, while the ocular complications of SARS-CoV-2-infected patients have not been reported generally. Herein, we focus on two major receptors of SARS-CoV-2, ACE2 and CD147 (BSG), in human ocular cells, and interpret the potential roles of coronaviruses in human ocular tissues and diseases.

Severe acute respiratory syndrome coronavirus-2: implications for blood safety and sufficiency

BACKGROUND AND OBJECTIVE

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a novel coronavirus, first identified in China at the end of 2019 and has now caused a worldwide pandemic. In this review, we provide an overview of the implications of SARS-CoV-2 for blood safety and sufficiency.

MATERIAL AND METHOD

We searched the PubMed database, the preprint sites bioRxiv and medRxiv, the websites of the World Health Organization, European Centre for Disease Prevention and Control, the US Communicable Diseases Center and monitored ProMed updates.

RESULTS

An estimated 15%-46% of SARS-CoV-2 infections are asymptomatic. The reported mean incubation period is 3 to 7 days with a range of 1-14 days. The blood phase of SARS-CoV-2 appears to be brief and low level, with RNAaemia detectable in only a small proportion of patients, typically associated with more severe disease and not demonstrated to be infectious virus. An asymptomatic blood phase has not been demonstrated. Given these characteristics of SARS-CoV-2 infection and the absence of reported transfusion transmission (TT), the TT risk is currently theoretical. To mitigate any potential TT risk, but more importantly to prevent respiratory transmission in donor centres, blood centres can implement donor deferral policies based on travel, disease status or potential risk of exposure.

CONCLUSION

The TT risk of SARS-CoV-2 appears to be low. The biggest risk to blood services in the current COVID-19 pandemic is to maintain the sufficiency of the blood supply while minimizing respiratory transmission of SARS-CoV-19 to donors and staff while donating blood.

Natural history of COVID-19 and therapeutic options

Introduction: COVID-19 presents benign forms in young patients who frequently present with anosmia. Infants are rarely infected, while severe forms occur in patients over 65 years of age with comorbidities, including hypertension and diabetes. Lymphopenia, eosinopenia, thrombopenia, increased lactate dehydrogenase, troponin, C-reactive protein, D-dimers and low zinc levels are associated with severity.Areas covered: The authors review the literature and provide an overview of the current state of knowledge regarding the natural history of and therapeutic options for COVID-19. Expert opinion: Diagnosis should rely on PCR and not on clinical presumption. Because of discrepancies between clinical symptoms, oxygen saturation or radiological signs on CT scans, pulse oximetry, and radiological investigation should be systematic. The disease evolves in successive phases: an acute virological phase, and, in some patients, a cytokine storm phase; an uncontrolled coagulopathy; and an acute respiratory distress syndrome. Therapeutic options include antivirals, oxygen therapy, immunomodulators, anticoagulants and prolonged mechanical treatment. Early diagnosis, care, and implementation of an antiviral treatment; the use of immunomodulators at a later stage; and the quality of intensive care are critical regarding mortality rates. The higher mortality observed in Western countries remains unexplained. Pulmonary fibrosis may occur in some patients. Its future is unpredictable.

Body Localization of ACE-2: On the Trail of the Keyhole of SARS-CoV-2

The explosion of the new coronavirus (SARS-CoV-2) pandemic has brought the role of the angiotensin converting enzyme 2 (ACE2) back into the scientific limelight. Since SARS-CoV-2 must bind the ACE2 for entering the host cells in humans, its expression and body localization are critical to track the potential target organ of this infection and to outline disease progression and clinical outcomes. Here, we mapped the physiological body distribution, expression, and activities of ACE2 and discussed its potential correlations and mutal interactions with the disparate symptoms present in SARS-CoV-2 patients at the level of different organs. We highlighted that despite during SARS-CoV-2 infection ACE2-expressing organs may become direct targets, leading to severe pathological manifestations, and subsequent multiple organ failures, the exact mechanism and the potential interactions through which ACE2 acts in these organs is still heavily debated. Further scientific efforts, also considering a personalized approach aimed to consider specific patient differences in the mutual interactions ACE2-SARS-CoV-2 and the long-term health effects associated with COVID-19 are currently mandatory.

Pathogenesis-directed therapy of 2019 novel coronavirus disease

The 2019 novel coronavirus disease (COVID-19) now is considered a global public health emergency. One of the unprecedented challenges is defining the optimal therapy for those patients with severe pneumonia and systemic manifestations of COVID-19. The optimal therapy should be largely based on the pathogenesis of infections caused by this novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since the onset of COVID-19, there have been many prepublications and publications reviewing the therapy of COVID-19 as well as many prepublications and publications reviewing the pathogenesis of SARS-CoV-2. However, there have been no comprehensive reviews that link COVID-19 therapies to the pathogenic mechanisms of SARS-CoV-2. To link COVID-19 therapies to pathogenic mechanisms of SARS-CoV-2, we performed a comprehensive search through MEDLINE, PubMed, medRxiv, EMBASE, Scopus, Google Scholar, and Web of Science using the following keywords: COVID-19, SARS-CoV-2, novel 2019 coronavirus, pathology, pathologic, pathogenesis, pathophysiology, coronavirus pneumonia, coronavirus infection, coronavirus pulmonary infection, coronavirus cardiovascular infection, coronavirus gastroenteritis, coronavirus autopsy findings, viral sepsis, endotheliitis, thrombosis, coagulation abnormalities, immunology, humeral immunity, cellular immunity, inflammation, cytokine storm, superantigen, therapy, treatment, therapeutics, immune-based therapeutics, antiviral agents, respiratory therapy, oxygen therapy, anticoagulation therapy, adjuvant therapy, and preventative therapy. Opinions expressed in this review also are based on personal experience as clinicians, authors, peer reviewers, and editors. This narrative review linking COVID-19 therapies with pathogenic mechanisms of SARS-CoV-2 has resulted in six major therapeutic goals for COVID-19 therapy based on the pathogenic mechanisms of SARS-CoV-2. These goals are listed below: 1. The first goal is identifying COVID-19 patients that require both testing and therapy. This is best accomplished with a COVID-19 molecular test from symptomatic patients as well as determining the oxygen saturation in such patients with a pulse oximeter. Whether a symptomatic respiratory illness is COVID-19, influenza, or another respiratory pathogen, an oxygen saturation less than 90% means that the patient requires medical assistance. 2. The second goal is to correct the hypoxia. This goal generally requires hospitalization for oxygen therapy; other respiratory-directed therapies such as prone positioning or mechanical ventilation are often used in the attempt to correct hypoxemia due to COVID-19. 3. The third goal is to reduce the viral load of SARS-CoV-2. Ideally, there would be an oral antiviral agent available such as seen with the use of oseltamivir phosphate for influenza. This oral antiviral agent should be taken early in the course of SARS-CoV-2 infection. Such an oral agent is not available yet. Currently, two options are available for reducing the viral load of SARS-CoV-2. These are post-Covid-19 plasma with a high neutralizing antibody titer against SARS-CoV-2 or intravenous remdesivir; both options require hospitalization. 4. The fourth goal is to identify and address the hyperinflammation phase often seen in hospitalized COVID-19 patients. Currently, fever with an elevated C-reactive protein is useful for diagnosing this hyperinflammation syndrome. Low-dose dexamethasone therapy currently is the best therapeutic approach. 5. The fifth goal is to identify and address the hypercoagulability phase seen in many hospitalized COVID-19 patients. Patients who would benefit from anticoagulation therapy can be identified by a marked increase in d-dimer and prothrombin time with a decrease in fibrinogen. To correct this disseminated intravascular coagulation-like phase, anticoagulation therapy with low molecular weight heparin is preferred. Anticoagulation therapy with unfractionated heparin is preferred in COVID-19 patients with acute kidney injuries. 6. The last goal is prophylaxis for persons who are not yet infected. Potential supplements include vitamin D and zinc. Although the data for such supplements is not extremely strong, it can be argued that almost 50% of the population worldwide has a vitamin D deficiency. Correcting this deficiency would be beneficial regardless of any impact of COVID-19. Similarly, zinc is an important supplement that is important in one's diet regardless of any effect on SARS-CoV-2. As emerging therapies are found to be more effective against the SARS-CoV-2 pathogenic mechanisms identified, they can be substituted for those therapies presented in this review.

Digital PCR is a sensitive new technique for SARS-CoV-2 detection in clinical applications

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Digital PCR is a sensitive new technique for SARS-CoV-2 detection in clinical applications.

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Digital PCR would substantially reduce the rates of false-negative COVID-19 test results, in particular those pertaining to asymptomatic carriers.

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Real-time reverse-transcriptase (RT)-PCR is a fast and convenient method for viral nucleic acid detection, but it’s results can be compromised by numerous factors and can yield false-negative results.

The global coronavirus disease 2019 (COVID-19) pandemic has posed great challenges in people’s daily lives. Highly sensitive laboratory techniques played a critical role in clinical COVID-19 diagnosis and management. In this study the feasibility of using a new digital PCR-based detection assay for clinical COVID-19 diagnosis was investigated by comparing its performance with that of RT-PCR. Clinical patient samples and samples obtained from potentially contaminated environments were analyzed. The study included 10 patients with confirmed COVID-19 diagnoses, 32 validated samples of various types derived from different clinical timepoints and sites, and 148 environmentally derived samples. SARS-CoV-2 nucleic acids were more readily detected in respiratory tract samples (35.0%). In analyses of environmentally derived samples, the positivity rate of air samples was higher than that of surface samples, probably due to differences in virus concentrations. Digital PCR detected SARS–CoV–2 in several samples that had previously been deemed negative, including 3 patient-derived samples and 5 environmentally derived samples. In this study digital PCR exhibited higher sensitivity than conventional RT-PCR, suggesting that it may be a useful new method for clinical SARS-CoV-2 detection. Improvement of SARS-CoV-2 detection would substantially reduce the rates of false-negative COVID-19 test results, in particular those pertaining to asymptomatic carriers.

An Ophthalmic Insight into Novel Coronavirus 2019 Disease: A Comprehensive Review of the Ocular Manifestations and Clinical Hazards

PURPOSE

To discuss the ocular manifestations provoked by novel coronavirus 2019 (COVID-19) disease in humans, the natural history of the disease in the eye, and its treatment.

METHODS

We designed a narrative review of the ocular manifestations of COVID-19 based on the literature published till July 30, 2020. The databases were PubMed, Scopus, Cochrane Library, Google Scholar, and ScienceDirect. The inclusion criteria were (1) all types of clinical studies and (2) the topic was COVID-19 and its association to the eye regarding the current guidelines.

RESULTS

From 168 abstracts screened, 61 papers fully filled the inclusion criteria after the full-text screening. The 61 records include 13 case reports, 17 prospective (case series or cross-sectional) studies, 8 retrospective studies, 12 literature reviews (one systematic review), and 11 letters to the editor. The majority of the papers agreed that ophthalmic manifestations due to COVID-19 were few and rarely encountered. The main ocular pathology seemed to be conjunctivitis, where the viral polymerase chain reaction also happened to be most detectable. Posterior segment or neuro-ophthalmic manifestations were scarce. Viral genome detection in the eye as well as viral portal of entry to the globe is still vague.

CONCLUSION

The exact incidence of ocular manifestations in COVID-19 disease is uncertain. Conjunctivitis is the most prevalent ocular manifestation. It is still a debate whether the eye is a portal of entry for infection.

Systematic Review of Ocular Involvement of SARS-CoV-2 in Coronavirus Disease 2019

Purpose of Review

Studies have reported ocular involvement in the coronavirus disease 2019 (COVID-19), with SARS-CoV-2 having been detected in ocular swab samples. This has implicated the eye as a portal of transmission. The aim of this systemic review is to summarise and discuss the current literature regarding ocular involvement of SARS-CoV-2 in COVID-19.

Recent Findings

In this systematic review, the prevalence of ocular symptoms and signs was low (from 0 to 31.58%) and conjunctivitis was a relatively rare occurrence. The rate of detection of SARS-CoV-2 in the ocular swab samples was low as well and this ranged from 0 to 11.11%. The development of ocular symptoms and signs was not always accompanied by the detection of SARS-CoV-2 in the ocular swab samples. The opposite was described as well. This may reflect issues related to the characteristics of SARS-CoV-2 and of the study design. Nonetheless, the nature of research in a pandemic is that conclusions can change as more information is obtained.

Summary

Whilst the eye is unlikely to be a main transmission route, we need to consider the possibilities of conjunctivitis as a presenting complaint and of the eye playing a role in the transmission of SARS-CoV-2. Furthermore, we need to take the appropriate precautions in our practice. Further studies are needed to evaluate the viral tropism of SARS-CoV-2 and its role in the eyes.

[Evolving Consensus of International Uveitis Study Group, Intraocular Inflammation Society, and Foster Ocular Inflammation Society with Uveitis in the Time of COVID-19 Infection]

This document summarizes the experience of the International Uveitis Study Group (IUSG), the Intraocular Inflammation Society (IOIS) and the Foster Ocular Inflammation Society (FOIS) and can aid as a guide for the treatment of uveitis patients in the era of COVID-19 pandemic.

Evolving Consensus Experience of the IUSG-IOIS-FOIS with Uveitis in the Time of COVID-19 Infection

This document summarizes the experience of the International Uveitis Study Group (IUSG), the Intraocular Inflammation Society (IOIS), and the Foster Ocular Inflammation Society (FOIS) and can aid as a guide for the treatment of uveitis patients in the era of COVID-19 pandemic.

Diagnosis of chronic stage of hypertensive retinopathy based on spectral domain optical coherence tomography

Hypertensive retinopathy refers to the retinal vascular changes associated with systemic arterial hypertension. Hypertensive retinopathy can be divided into chronic and acute phases. A cross-sectional study was performed to explore a method of measurement in the diameters of retinal vessels for diagnosis of chronic hypertensive retinopathy based on spectral domain optical coherence tomography (SD-OCT). The central retinal artery diameter (CRAD), the central retinal vein diameter (CRVD), and the artery-to-vein ratio (AVR) were measured. A total of 119 subjects with 119 eyes were included in this study, in which 56 subjects with 56 eyes were included in hypertensive group and 63 subjects with 63 eyes were included in normotensive group. There were significant differences between the two groups in the CRAD (t = -2.14, P = .04) and the AVR (t = -2.59, P = .01). The cutoff point of 0.75 was determined by receiver operating characteristic (ROC) curve (area under the curve, AUC 0.786; 95% confidence interval, 95% CI 0.70-0.87). Multivariate logistic regression analysis showed the probability of AVR below to 0.75 was more in patients with high systolic blood pressure (odds ratio OR 4.39; P = .048), more in male (OR 4.15; P = .004) and more in smokers (OR 5.80; P = .01). Bland-Altman plots showed small mean bias between the measurements of the two technicians in the CRAD, the CRVD, and the AVR. In summary, application of SD-OCT is an accurate, reproducible, convenient method for measuring the diameters of retinal vessels. It is valuable for the diagnosis of chronic stage of hypertensive retinopathy.

Ocular Surface Expression of SARS-CoV-2 Receptors

PURPOSE

The spike proteins of SARS-CoV-2 interact with ACE2 or basigin/CD147 receptors, regulating human-to-human transmissions of COVID-19 together with serine protease TMPRSS2. The expression of these receptors on the ocular surface is unknown.

MATERIAL AND METHODS

Gene expression of SARS-CoV-2 receptors was investigated in conjunctival epithelial cell samples and in ex-vivo cornea samples using microarray or transcriptome sequencing.

RESULTS

ACE2 is expressed in conjunctival samples at a low level, while BSG and TMPRSS2 are expressed at intermediate levels in both conjunctiva and cornea. Other receptors such as ANPEP, AGTR2 are expressed at low level in the conjunctiva. Two RNA editing enzymes involved in antiviral responses, APOBEC3A, and ADAR-1 were also highly expressed.

CONCLUSIONS

The ocular surface may represent an entry point for the SARS-CoV-2 in the human body. The conjunctiva and the cornea can adopt antiviral countermeasures which may explain the low prevalence of eye involvement.

Coronavirus Disease 2019 Presenting as Conjunctivitis

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by a novel coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The world is currently challenged to handle this pandemic. The common symptoms of COVID-19 are fever, cough, fatigue, and shortness of breath. There are few reports on the association of SARS-CoV-2 with ocular abnormalities including conjunctivitis. We report a case of a 54-year-old woman who presented solely with conjunctivitis subsequently diagnosed with COVID-19. A lack of full history of her travel abroad was another issue leading to a delay in evaluating her COVID-19 status that increased the infection risk to her managing team. Thus, primary care practitioners should be suspicious of this atypical feature of COVID-19, thus enabling us to identify such patients at entry points. Maintaining safety measures while managing patients is also crucial.

COVID-19: Ophthalmological Aspects of the SARS-CoV 2 Global Pandemic

PURPOSE

To perform a systematic analysis of articles on the ophthalmological implications of the global COVID-19 pandemic.

METHODS

PubMed.gov was searched for relevant articles using the keywords "COVID-19", "coronavirus", and "SARS-CoV-2" in conjunction with "ophthalmology" and "eye". Moreover, official recommendations of ophthalmological societies were systematically reviewed, with a focus on the American Academy of Ophthalmology (AAO) and the Royal College of Ophthalmologists (RCOphth).

RESULTS

As of April 16, 2020, in total, 21 peer-reviewed articles on the ophthalmological aspects of COVID-19 were identified. Of these, 12 (57.1%) were from Asia, 6 (28.6%) from the United States of America, and 3 (14.3%) from Europe. There were 5 (23.8%) original studies, 10 (47.6%) letters, 3 (14.2%) case reports, and 3 (14.2%) reviews. These articles could be classified into the topics "Modes and prevention of (ocular) transmission", "Ophthalmological manifestations of COVID-19", "Clinical guidance concerning ophthalmological practice during the COVID-19 pandemic", and "Practical recommendations for clinical infrastructure". Practical recommendations could be extracted from official statements of the AAO and the RCOphth.

CONCLUSION

Within a short period, a growing body of articles has started to elucidate the ophthalmological implications of COVID-19. As the eye can represent a route of infection (actively via tears and passively via the nasoacrimal duct), ophthalmological care has to undergo substantial modifications during this pandemic. In the eye, COVID-19 can manifest as keratoconjunctivitis.

Modifications of emergency dental clinic protocols to combat COVID-19 transmission

During the COVID-19 pandemic, incidence rates for dental diseases will continue unabated. However, the intent to prevent the spread of this lethal respiratory disease will likely lead to reduced treatment access due to restrictions on population movements. These changes have the potential to increase dental-related emergency department visits and subsequently contribute to greater viral transmission. Moreover, dentists experience unique challenges with preventing transmission due to frequent aerosol-producing procedures. This paper presents reviews and protocols implemented by directors and residents at the Dental College of Georgia to manage a dental emergency clinic during the COVID-19 pandemic. The methods presented include committee-based prioritization of dental patients, a multilayered screening process, team rotations with social and temporal spacing, and modified treatment room protocols. These efforts aid in the reduction of viral transmission, conservation of personal protective equipment, and expand provider availability. These protocols transcend a university and hospital-based models and are applicable to private and corporate models.

COVID-19: Present and Future Challenges for Dental Practice

COVID-19 was declared a pandemic by the World Health Organization, with a high fatality rate that may reach 8%. The disease is caused by SARS-CoV-2 which is one of the coronaviruses. Realizing the severity of outcomes associated with this disease and its high rate of transmission, dentists were instructed by regulatory authorities, such as the American Dental Association, to stop providing treatment to dental patients except those who have emergency complaints. This was mainly for protection of dental healthcare personnel, their families, contacts, and their patients from the transmission of virus, and also to preserve the much-needed supplies of personal protective equipment (PPE). Dentists at all times should competently follow cross-infection control protocols, but particularly during this critical time, they should do their best to decide on the emergency cases that are indicated for dental treatment. Dentists should also be updated on how this pandemic is related to their profession in order to be well oriented and prepared. This overview will address several issues concerned with the COVID-19 pandemic that directly relate to dental practice in terms of prevention, treatment, and orofacial clinical manifestations.