Laboratory results in ocular viral diseases: implications in clinical-laboratory correlation

Evaluation of multiplex real-time polymerase chain reaction for the detection of herpes simplex virus-1 and 2 and varicella-zoster virus in corneal cells from normal subjects and patients with keratitis in India

Purpose

To determine the presence of herpes simplex virus and varicella zoster virus (HSV 1 and 2, VZV) in the cornea of normal subjects by multiplex real time quantitative (qPCR) assay and evaluate its utility in the diagnosis of viral keratitis.

Methods

Corneal epithelial cells from 33 eyes of 22 patients undergoing photorefractive keratectomy surgery (controls) and 50 corneal scrapings from 50 patients with suspected HSV keratitis were analyzed for the presence of HSV1 by conventional PCR and for presence of HSV1 and 2 and/or VZV by multiplex real-time PCR. Corneal scrapings of patients were also tested for HSV1 antigen by immunofluorescence assay (IFA). The results were compared and clinical records reviewed.

Results

HSV1 and VZV DNA were detected in 8/33 controls (mean-14.3 ± 7.96, range: 3-29.1 copies/mL) and 2/33 controls (mean-10.7 ± 10.9, range 3-18.5 copies/ml) respectively. HSV2 was not detected in any of the controls. Copy numbers above the mean + 1SD of controls were considered significant for viral load in patient samples. Significantly higher number of corneal scrapings (39/50, 78%) from patients were positive for HSV1 (1.2 × 10⁶ copies/mL ± 3.7 × 10⁶ copies/mL) by real time qPCR compared to IFA (11/48, 23%, P value 0.0001) and conventional PCR (20/50, 40%, P value 0.0002). Double infection with HSV-1 (1.5 × 10⁷ copies/ml) and HSV-2 (3.57 × 10⁴ copies/ml) in one case and VZV infection (1.03 × 10² copies/ml) in another was also detected by the multiplex real-time PCR.

Conclusion

Multiplex real-time PCR reliably detects HSV1 and 2 and VZV DNA and is ideal for the diagnosis of HSV and VZV keratitis in an ocular microbiology laboratory.

Utility of HSV Serology for Chronic Corneal Pathology

OBJECTIVES

The purpose of this study is to determine the utility of obtaining herpes simplex virus (HSV) serology for patients presenting with chronic corneal pathology of unknown etiology for which HSV is a diagnostic consideration.

METHODS

A retrospective analysis was performed of all patients presenting to one cornea specialist (J.M.G.) between August 2011 and April 2018 with a chronic (>6 weeks) corneal condition for which HSV was suspected and serology was performed. Patient demographics, clinical presentation, treatment, final diagnosis, and follow-up duration were recorded.

RESULTS

Fifty-four patients with a median age of 52 (range: 5-85) years were included in the study. Patients were classified by presenting clinical features as corneal ulcer (46.2%), stromal keratitis (24.1%), superficial keratitis (18.5%), or keratouveitis (11.1%). The seroprevalence of HSV-1 and HSV-2 antibodies were 42.6% and 18.5%, including 5 patients (9.3%) positive for both HSV-1 and HSV-2. Serology impacted management for all patients with negative titers (48.1%), defined as discontinuing antiviral medication, electing not to start antiviral medication, or continuing antiviral medication for a non-HSV etiology (e.g., varicella zoster keratitis). No patients with HSV serology were ultimately diagnosed with HSV keratitis. Median follow-up duration was 1.5 years (range 0.8-6.6 years).

CONCLUSION

Although only useful when negative, our study confirms that serology may be useful for excluding HSV as a diagnostic consideration for patients presenting with chronic corneal pathology. The seroprevalence of HSV antibodies for our patient cohort was comparable with previous population-based studies.

The Epidemic Genotypes of Human Adenovirus in Outpatient Children with Adenoviral Conjunctivitis from 2011 to 2012 in Jiangxi, China

BACKGROUND

Human adenoviruses (HAdV) are a common cause of viral conjunctivitis, making surveillance of them from sporadic cases of conjunctivitis important.

METHODS

To acquire a better understanding of the epidemic genotypes of HAdV in outpatient children with adenoviral conjunctivitis in Jiangxi Province, China (2011-2012), 179 samples from cases with a high suspicion of HAdV were analyzed by PCR. Samples confirmed to be HAdV-positive by PCR were cultured in Hep-2 cells to isolate the viruses, which were then identified through hexon gene sequencing.

RESULTS

The adenoviral conjunctivitis positivity rate was 74.86% (134/179), from which 71.64% (96/134) were infections in boys, and 92.54% (124/134) were infections in children under 5 years of age. Sixty-nine HAdV strains were isolated from the positive samples and 69 sequences were obtained. Phylogenetic analysis indicated that 33 strains (47.82%) clustered with HAdV-B7, 21 (30.43%) with HAdV-B3, 6 (8.70%) with HAdV-B55, 6 (8.70%) with HAdV-E4, 1 with HAdV-B21 (1.45%), 1 with HAdV-D37 (1.45%), and 1 with HAdV-D64 (1.45%).

CONCLUSIONS

This is the first identification of HAdV-B55 relating to adenoviral conjunctivitis in China. These findings provide a firm basis for future surveillance of adenoviral conjunctivitis in China or other East Asian regions.

Evaluation of the antiviral potential of the soluble forms of glycoprotein D receptors on ocular herpes caused by HSV-1 and HSV-2 infections in a transgenic mouse model

Ocular herpes, caused by herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) infections, remains an important corneal disease, which may result in loss of vision. Because the frequency of acyclovir resistance in HSV has increased, novel antiviral agents are needed for therapeutic approaches to ocular herpes. Several studies have demonstrated that fusion proteins containing entire ectodomain of HSV glycoprotein D receptors, including herpesvirus entry mediator A (HVEM), nectin-1 and nectin-2, and the Fc portion of human IgG (HVEMIg, nectin-1Ig, and nectin-2Ig, respectively), can exert antiviral effects in vitro and in vivo. Here, to evaluate the antiviral potential of HVEMIg, nectin-1Ig, and nectin-2Ig against ocular infections with HSV, transgenic mice expressing these fusion proteins were ocularly inoculated with HSV-1 and HSV-2. Transgenic mouse lines expressing HVEMIg and nectin-1Ig showed marked resistance to ocular herpes; on the other hand, mouse lines expressing nectin-2Ig did not. Furthermore, to investigate the therapeutic effects of nectin-1Ig, which can neutralize HSVs in vitro against ocular disease, transgenic mouse serum containing nectin-1Ig was dropped into the eyes of wild-type mice after HSV infection. Reduction of severe symptoms could be observed in mice treated with nectin-1Ig serum. These results warrant further study of soluble HVEM and nectin-1 products as preventive and therapeutic agents against ocular herpes caused by HSV-1 and HSV-2 infections, especially nectin-1Ig as a new eye drop.

ADenoVirus Initiative Study in Epidemiology (ADVISE): Results of a multicentric epidemiology study in Spain

OBJECTIVE

Non-interventional, observational, epidemiology study to assess clinical characteristics and frequency of adenovirus conjunctivitis diagnosed by AdenoPlus^® in patients who presented with signs and symptoms of acute conjunctivitis. Safety aspects during use of the test were analyzed as well.

METHOD

This analysis presents the data obtained from the 386 patients enrolled in Spain. Patients had to present with acute signs and symptoms of conjunctivitis ≤7days. The minimum age was 1year old. Patients who had already used local antiviral therapies, topical steroids or immuno-modulators were not allowed to enter the study. A standardized questionnaire was used to collect patient's ocular history and test results.

RESULTS

A total of 386 patients were recruited in 22 sites, being analyzed 329 patients. Among them, the percentage of "AdenoPlus^® positive" was 36,2% (119/329). Before the test was performed, in 84,1% of the cases, investigators believed that the conjunctivitis was of viral origin but only 50,3% of the investigators had their clinical assessment confirmed by the test. Patients who tested positive for adenoviral conjunctivitis presented higher percentages of signs and symptoms than the rest of the patients.

CONCLUSIONS

None of the signs or symptoms could be qualified as pathognomonic of the disease, being difficult for the clinicians to perform an accurate diagnosis. AdenoPlus^® test is an antigen based immunoassay test that detects the presence of adenovirus directly from tears, and it can be an useful tool to help early differential diagnosis in patients with conjunctivitis signs and symptoms lasting for less than or equal to 7days.

Molecular identification of viral agents associated with acute conjunctivitis: a prospective controlled study

Background

Viral conjunctivitis are the most frequent infections in ophthalmology clinics. The diagnosis is usually relying on clinical findings and medical history. However, topical antibiotics are often used unnecessarily addition to symptomatic treatment because of unsure agents. We aimed to detect the Adenovirus, Coxsackievirus and Enterovirus from conjunctiva and pharyngeal samples of patients.

Methods

The conjunctiva and pharyngeal samples of the patients with conjunctivitis were taken by Virocult transport media and kept at −80 ̊C up to study day. Adenovirus spp, Enterovirus 70 and Enterovirus 71, Coxsackie A24 and Coxsackie A16 were detected by real-time PCR. Samples from healthy health care workers of ophthalmology clinic were used for control group.

Results

A total of 176 samples (conjunctival and pharyngeal samples of 62 patient and 26 healthy subjects) were included. The mean age of 34 (55.7%) male and 27 (44.3%) female patients was 34 ± 17. Twenty five (40.3%) of the patients were receiving antibiotic drops at first visit. The main etiologic agent in conjunctival samples was found to be Adenovirus (46/62, 74.2%) followed by Enterovirus 70 (4/62, 6.4%) and Enterovirus 71 (4/62, 6.4%). Coxsackievirus 16 and 24 were also found in 2 patients (1/62 each, 1.6%). Pharyngeal samples were also positive for Adenovirus (20/62, 32.3%), Enterovirus 70 and 71 (7/62, 11.3% and 5/62, 8.1% respectively), Coxsackievirus 16 and 24 (2/62, 3.2% and 1/61, 1.6%).

Conclusions

It is very difficult in viral conjunctivitis to make clinical differentiation caused by different agents because of common clinical signs and symptoms. In routine clinical work, the viral conjunctivitis usually related with Adenovirus. But almost one fourth of the patients’ conjunctivitis were not related to Adenovirus, which shows the importance of the laboratory diagnostics. True diagnosis plays an important role on prevention of contamination and unnecessary use of antibiotics in viral conjunctivitis.

Herpes simplex keratitis: challenges in diagnosis and clinical management

Herpes simplex virus is responsible for numerous ocular diseases, the most common of which is herpetic stromal keratitis. This is a recurrent infection of the cornea that typically begins with a subclinical infection of the cornea that establishes a latent infection of sensory ganglia, most often the trigeminal ganglia. Recurring infections occur when the virus is reactivated from latency and travels back to the cornea, where it restimulates an inflammatory response. This inflammatory response can lead to decreased corneal sensation, scarring, and blindness. The diagnosis of these lesions as the result of a recurrent herpes simplex virus infection can at times be problematic. Currently, herpetic stromal keratitis is diagnosed by its clinical presentation on the slit-lamp examination, but the literature does not always support the accuracy of these clinical findings. Other diagnostic tests such as polymerase chain reaction assay, enzyme-linked immunosorbent assay, immunofluorescent antibody, and viral cultures have provided more definitive diagnosis, but also have some limitations. That said, accurate diagnosis is necessary for proper treatment, in order to prevent serious consequences. Current treatment reduces the severity of lesions and controls further viral spread, but does not provide a cure.

Prevention of adenoviral eye infection: Review

Epidemic viral conjunctivitis caused by adenovirus is the most common infectious conjunctivitis. The exact incidence of adenoviral conjunctivitis is still poorly known, but there are two well-defined adenoviral keratoconjunctivitis clinical syndromes: epidemic keratoconjunctivitis (EKC) and pharyngoconjunctival fever (PCF). Epidemic keratoconjunctivitis is also the most severe form and presents with watery discharge, hyperemia, chemosis and ipsilateral lymphadenopathy. Diagnosis is mainly clinical, but its etiology can be confirmed using cell cultures, antigen detection, polymerase chain reaction or immune-chromatography. Multiple treatments have been tried for this disease, but none of them seem to be completely effective. Viruses are resistant to desiccation and certain common surface disinfectants. Prevention is the most reliable and recommended strategy to control this epidemic infection. Global epidemic surveillance system definitely needs to be established to monitor and analyze the epidemic conjunctivitis in the future. There is clearly a need for the national and the military public health institutions to work together on guidelines to handle future challenges.

Molecular detection and characterization through analysis of the hexon and fiber genes of Adenoviruses causing conjunctivitis in Tunisia, North Africa

Human adenoviruses (HAdVs) are common causes of conjunctivitis. This study describes the epidemiological features and characterizes by phylogenetic analysis HAdVs isolated from patients with conjunctivitis in Tunisia, North Africa. Data on out-patients presenting with conjunctivitis during 2 years (2012-2013) were analyzed. Conjunctival swabs obtained from 240 patients were assessed for the presence of HAdVs by PCR amplification on the fiber and hexon genes. Positive PCR products, together with those of nine viral isolates from previous years, were sequenced and analyzed phylogenetically. Conjunctivitis represented 11.5% of all reasons of consultations with a slight increase between mid-March and mid-June. Sixty-five percent of samples (n = 156) revealed positive by at least one PCR test. PCR amplification in the hexon gene was slightly more sensitive as compared to the fiber gene. Genotyping in the two genomic regions gave concordant results for almost all isolates. HAdV-D8 was the most predominant genotype (87.6%) and was detected continuously from 2000 to 2013. Minor co-circulating genotypes including HAdV-E4, HAdV-B3, HAdV-B55, and HAdV-D37 were identified; most of them were detected by amplification in the hexon gene. In conclusion, this work reports molecular data on adenoviral conjunctivitis from a region where such information is scarce and contributes to a better knowledge of the worldwide distribution of causative genotypes. It revealed a predominance and endemic circulation of HAdV-D8, a genotype that was mainly reported from epidemic keratoconjunctivitis. It shows that PCR amplification in two different genomic regions enhances the sensitivity of HAdV detection in clinical samples and the identification of minor genotypes. J. Med. Virol. 89:304-312, 2017. © 2016 Wiley Periodicals, Inc.

Acute conjunctivitis: truth and misconceptions

OBJECTIVE

Acute conjunctivitis is an extremely common condition and can be associated with significant morbidity and economic burden. Despite this, considerable controversy exists pertaining to the prevalence, diagnosis, management, and treatment of the condition. A panel of ophthalmology experts was assembled to review and discuss the current evidence based literature as it pertains to each of these persistent controversies.

METHODS AND SCOPE

An acute conjunctivitis round table symposium was convened at the American Academy of Ophthalmology meeting in Atlanta, November 2008. The expert panelists consisted of four academic ophthalmologists in the field of cornea and external disease, whose discussion was informed by an English language literature survey carried out on the PubMed database for the period of January 1972 to October 2008. A narrative summary was generated from the literature review and direct transcription of this event, from which this Review article was developed.

FINDINGS AND CONCLUSIONS

Considerable light has been shed on acute microbial conjunctivitis and especially those cases caused by adenovirus. Many of the myths that have perpetuated for years have been debunked by emerging evidence. The advent and the implementation of better diagnostic tools and anti-viral medications will help clinicians to improve their diagnostic accuracy, improve management and treatment decisions, and ultimately benefit patients while saving overall healthcare costs.

HVEM and nectin-1 are the major mediators of herpes simplex virus 1 (HSV-1) entry into human conjunctival epithelium

PURPOSE

The human conjunctiva is a natural target for herpes simplex virus (HSV)-1 infection. The goals of this study were to investigate the cellular and molecular mechanisms of HSV-1 entry into human conjunctival epithelial (HCjE) cells. Specific features of entry studied included the method of initial viral binding to cells, pH dependency, and expression and usage of specific HSV-1 entry receptors.

METHODS

To observe HSV-1 initial binding, live cell imaging was performed on HSV-1-infected HCjE cells. Reporter HSV-1 virions expressing beta-galactosidase were used to determine entry of wild-type HSV-1(KOS) and a mutant, HSV-1(KOS)Rid1, into HCjE cells. HSV-1 replication in HCjE cells was determined by plaque assays. Lysosomotropic agents were used to determine whether viral entry was pH dependent. Reverse transcription (RT)-PCR, flow cytometry, and immunohistochemistry were used to determine the expression of receptors. Receptor-specific siRNAs were used to define the role of individual entry receptors.

RESULTS

HSV-1 virions attach to filopodia present on HCjE cells and use them to reach the cell body for entry. Cultured HCjE cells demonstrate susceptibility to HSV-1 entry and form plaques confirming viral replication. Blocking vesicular acidification significantly reduces entry, implicating a pH-dependent mode of entry. Multiple assays confirm the expression of entry receptors nectin-1, HVEM, and 3-O-sulfated heparan sulfate (3-OS HS) on the HCjE cell membrane. Knocking down of gD receptors by siRNAs interference implicates nectin-1 and HVEM as the major mediators of entry.

CONCLUSIONS

HSV-1 entry into HCjE cells is a pH-dependent process that is aided by targeted virus travel on filopodia. HCjE cells express all three major entry receptors, with nectin-1 and HVEM playing the predominant role in mediating entry.