Epidemiology of Keratoconjunctivitis Across India from 2017 to 2019: A Multicentric Hospital-Based Study

PURPOSE

Conjunctivitis is one of the most common ocular conditions in clinical practice. Human adenoviruses have been the common causative agents known to cause epidemic kerato-conjunctivitis (EKC) in India from 1996 to 2019 with a positivity range of 13.8%-65.2%. The current study was initiated to throw light on the distribution of keratoconjunctivitis causing agents across India covering a span of 3 years.

METHODS

A total of 709 swabs were collected from patients in viral transport medium (VTM), and real-time PCR was done to identify agents including Adenovirus (HAdV), Enterovirus, HSV, and Chlamydia.

RESULTS

47.8% of the samples were positive for HAdV followed by HSV (3.4%), Enterovirus (2.7%), and Chlamydia (0.6%). Overall, 386 people (54.4%) tested positive for one of these infections, with Chandigarh (88.4%) and Port Blair (71.7%) showing higher positivity rate. Pre-auricular lymphadenopathy and follicles were significantly associated with increased risk of conjunctivitis.

CONCLUSION

Epidemiology of keratoconjunctivitis in the current study revealed HAdV to be predominant causative agent. Knowledge gained in such epidemiological studies guide us in outbreak expectations, limit antibiotic over-prescription, and enhance disease prevention.

Adenoviral Conjunctivitis in the Andaman Islands: A Clinical and Molecular Epidemiological Study

Introduction Human adenoviruses are common causes of many acute illnesses, and keratoconjunctivitis is one of them. Acute infections, if left untreated, can progress to severity, thus causing morbidities and mortalities. It belongs to the mastadenovirus family and is characterized by seven subgenus, i.e., A-G; among those, Adenovirus D8 is the most common type associated with keratoconjunctivitis. Methodology A hospital-based study was conducted, and the samples were collected from GB Pant Hospital, Port Blair, Dr Agarwals Eye Hospital, Port Blair, from August 2017 to December 2022. Clinical data and demographic details were followed by conjunctival swab sample collection from suspected keratoconjunctivitis patients. Samples were subjected to molecular screening, and Sanger sequencing was carried out for positive samples. Results Out of 506 conjunctival samples, a prevalence of 24.9% (n=126) was observed, and the commonest type circulating among the population of Andaman was Adenovirus D8. The major symptoms associated were eye redness (87.30%, n=110), followed by watering (81.75%, n=103), eye pain (72.22%, n=91), eye itching (61.11%, n=77), and discharge (50%, n=63). Conclusion In clinical research, ocular infections are one of the underrated fields. However, the study revealed the high prevalence of adenoviral infection among the suspected patients. Thus, there is a need for proper surveillance and timely diagnosis of such infections, as their severity may lead to loss of vision.

Viral Conjunctivitis

Viruses account for 80% of all cases of acute conjunctivitis and adenovirus; enterovirus and herpes virus are the common causative agents. In general, viral conjunctivitis spreads easily. Therefore, to control the spread, it is crucial to quickly diagnose illnesses, strictly implement hand washing laws, and sanitize surfaces. Swelling of the lid margin and ciliary injection are subjective symptoms, and eye discharge is frequently serofibrinous. Preauricular lymph node swelling can occasionally occur. Approximately 80% of cases of viral conjunctivitis are caused by adenoviruses. Adenoviral conjunctivitis may become a big global concern and may cause a pandemic. Diagnosis of herpes simplex viral conjunctivitis is crucial for using corticosteroid eye solution as a treatment for adenovirus conjunctivitis. Although specific treatments are not always accessible, early diagnosis of viral conjunctivitis may help to alleviate short-term symptoms and avoid long-term consequences.

Molecular analysis of human adenoviral keratoconjunctivitis cases: Results of a 2-year survey

Objective: This study aimed to determine the adenovirus genotypes and their epidemiological features between January 2018 and November 2019, in Istanbul, Turkey. Material and Methods: Conjunctival swab samples were obtained from patients who were clinically diagnosed with keratoconjunctivitis. Samples were screened with an Adeno Detector kit (Rapid Pathogen Screening, RPS Inc., South Williamsport, PA). Nucleic acid extraction and amplification were performed with the ADENOVIRUS ELITe MGB® kit in the ELITe In Genius instrument (Elitech Group, Torino, Italy). For subtyping of the strains, sequencing primers targeted the ‘Hypervariable Region 7’ (HVR-7) of the hexon gene were used. DNA sequence analysis (n:72) was performed with ABI PRISM® 3100 Genetic Analyzer (Applied Biosystems, USA), and subtyping was done by BLAST analysis. Results: The median viral load in the samples (n: 77) was 7 log10 copies/mL (IQR: 4.5-7.4 log10 copies/mL). The clinical finding score was found to be significantly higher in the high viral load group (Adenovirus DNA≥6 Log 10 copies/mL) than in the low viral load group (Adenovirus DNA

An adenovirus-vectored RVF vaccine confers complete protection against lethal RVFV challenge in A129 mice

Instruction: Rift valley fever virus (RVFV) is a mosquito-transmitted bunyavirus that causes severe disease in animals and humans. Nevertheless, there are no vaccines applied to prevent RVFV infection for human at present. Therefore, it is necessary to develop a safe and effective RVFV vaccine. Methods: We generated Ad5-GnGcopt, a replication-deficient recombinant Ad5 vector (human adenovirus serotype 5) expressing codon-optimized RVFV glycoproteins Gn and Gc, and evaluated its immunogenicity and protective efficacy in mice. Results and Discussion: Intramuscular immunization of Ad5-GnGcopt in mice induces strong and durable antibody production and robust cellular immune responses. Additionally, a single vaccination with Ad5-GnGcopt vaccination can completely protect interferon-α/β receptor-deficient A129 mice from lethal RVFV infection. Our work indicates that Ad5-GnGcopt might represent a potential vaccine candidate against RVFV. However, further research is needed, first to confirm its efficacy in a natural animal host, and ultimately escalate as a potential vaccine candidate for humans.

Human adenovirus in municipal solid waste leachate and quantitative risk assessment of gastrointestinal illness to waste collectors

Leachate is a variable effluent from waste management systems generated during waste collection and on landfills. Twenty-two leachate samples from waste collection trucks and a landfill were collected from March to December 2019 in the municipality of Rio de Janeiro (Brazil) and were analyzed for Human Adenovirus (HAdV), bacterial indicators and physico-chemical parameters. For viral analysis, samples were concentrated by ultracentrifugation and processed for molecular analysis using QIAamp Fast DNA Stool mini kit® for DNA extraction followed by nested-PCR and qPCR/PMA-qPCR TaqMan® system. HAdV was detected by nested-PCR in 100% (9/9) and 83.33% (12/13) of the truck and landfill leachate samples, respectively. Viral concentrations ranged from 8.31 × 10¹ to 6.68 × 10⁷ genomic copies per 100 ml by qPCR and PMA-qPCR. HAdV species A, B, C, and F were characterized using nucleotide sequencing. HAdV were isolated in A549 culture cells in 100% (9/9) and 46.2% (6/13) from truck and landfill leachate samples, respectively. Regardless of the detection methods, HAdV concentration was predicted by the quantity of total suspended solids. A quantitative microbial risk assessment was performed to measure the probability of gastrointestinal (GI) illness attributable to inadvertent oral ingestion of truck leachate, revealing the higher probability of disease for the direct splashing into the oral cavity (58%) than for the gloved hand-to-mouth (33%). In a scenario where waste collectors do not wear gloves as protective personal equipment, the risk increases to 67%. This is the first study revealing infectious HAdV in solid waste leachate and indicates a potential health risk for waste collectors.

Human Adenovirus Species D Interactions with Corneal Stromal Cells

Notable among the many communicable agents known to infect the human cornea is the human adenovirus, with less than ten adenoviruses having corneal tropism out of more than 100 known types. The syndrome of epidemic keratoconjunctivitis (EKC), caused principally by human adenovirus, presents acutely with epithelial keratitis, and later with stromal keratitis that can be chronic and recurrent. In this review, we discuss the current state of knowledge regarding the molecular biology of adenovirus infection of corneal stromal cells, among which the fibroblast-like keratocyte is the most predominant, in order to elucidate basic pathophysiologic mechanisms of stromal keratitis in the human patient with EKC.

Epidemic keratoconjunctivitis in India: electronic medical records-driven big data analytics report IV

AIMS

To describe the clinical profile of epidemic keratoconjunctivitis (EKC) in patients presenting to a multitier ophthalmology hospital network in India.

METHODS

This retrospective hospital-based study included 2 408 819 patients presenting between August 2010 and February 2020. Patients with a clinical diagnosis of EKC in at least one eye with a recent onset (≤1 week) were included as cases. The data were collected using the eyeSmart electronic medical record system.

RESULTS

Overall, 21 196 (0.9%) new patients were diagnosed with EKC, of which 19 203 (90.6%) patients reported a recent onset (≤1 week) and were included for analysis. The median age was 32 (IQR: 22-45) years and adults (84.5%) were commonly affected. Most of the patients were male (62.1%) and unilateral (53.4%) affliction was commoner. The most common presenting symptom was redness (63.7%), followed by watering (42.1%). Preauricular lymphadenopathy or tenderness was documented in 1406 (7.3%) cases at presentation. A minority of the eyes had visual impairment worse than 20/200 (7.8%) due to associated ocular comorbidities. The involvement of the cornea was seen in 7338 (38.2%) patients and corneal signs included subepithelial infiltrates (26.3%), epithelial defect (1.4%), corneal oedema (0.9%) and filaments (0.4%). Of the patients who had corneal involvement, 496 (2.6%) patients had a chronic course beyond 1 month of which 105 (0.5%) had a course beyond 1 year.

CONCLUSION

EKC is a self-limiting condition that is commonly unilateral and predominantly affects males. About one-third of the patients have corneal involvement which rarely has a chronic course.

Human mastadenovirus-B (HAdV-B)-specific E3-CR1β and E3-CR1γ glycoproteins interact with each other and localize at the plasma membrane of non-polarized airway epithelial cells

The E3 region of all simian and human types classified within species Human mastadenovirus B (HAdV-B) encodes two unique highly conserved ORFs of unknown function designated E3-CR1β and E3-CR1γ. We generated a HAdV-3 mutant encoding small epitope tags at the N-termini of both E3-CR1β and E3-CR1γ (HAdV-3 N-tag wt) and a double knock out (HAdV-3 N-tag DKO) mutant virus that does not express either protein. Our studies show that HAdV-3 E3-CR1β and E3-CR1γ are type I transmembrane proteins that are produced predominantly at late times post infection, are glycosylated, co-localize at the plasma membrane of non-polarized epithelial cells, and interact with each other. At their extreme C-termini HAdV-B E3-CR1β and E3-CR1γ possess a conserved di-leucine motif followed by a class II PDZ domain binding motif (PBM). HAdV-3 E3-CR1β and E3-CR1γ are dispensable for virus growth, progeny release, spread, and plaque formation in A549 cells.

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HAdV-B E3-CR1β and E3-CR1γ are type I transmembrane proteins.

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HAdV-B E3-CR1β and E3-CR1γ possess a C-terminal class II PDZ binding motif.

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HAdV-3 E3-CR1β and E3-CR1γ interact and co-localize at the plasma membrane.

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HAdV-3 E3-CR1β and E3-CR1γ are dispensable for virus progeny release and spread.

A Murine Monoclonal Antibody With Potent Neutralization Ability Against Human Adenovirus 7

B1-type human adenoviruses (HAdVs) HAdV-3, HAdV-7, and HAdV-55 have caused epidemics in North America, Asia, and Europe. However, to date, no adenovirus vaccines or antiviral drugs have been approved for general use. In the present work, a scFv-phage immune library was constructed and mouse monoclonal antibody (MMAb) 10G12 was obtained through selection. 10G12 is specific for HAdV-7 and binds the hexon loop1 and loop2 (LP12), resulting in strong neutralization activity against HAdV-7. Additionally, it is stable in serum and buffer at various pH values. The findings provide insight into adenovirus and antibody responses and may facilitate the design and development of adenovirus vaccines and antiviral drugs.

A treatment protocol for minimizing duration and complications of adenoviral epidemic keratoconjunctivitis

PURPOSE:

The purpose of the study was to assess the treatment protocol of topical 2.5% Povidone-Iodine (PovI) and 0.1% fluorometholone (FluM) for Adenoviral Epidemic keratoconjunctivitis (EKC) in reducing the duration and severity of the disease as compared to conventional treatment. This was a retrospective case–control study.

MATERIALS AND METHODS:

Cases were defined as patients with EKC receiving the treatment protocol and conjunctival swab taken for polymerase chain reaction. Controls were defined as similar patients receiving conventional treatment protocol. Forty-one cases and 35 controls were identified for analysis. Cases were treated with a protocol using 2.5% povidone-iodine eye drops and 0.1% FluM eye drops. Controls received conventional treatment until resolution of signs and symptoms. Both the groups were followed up for 1 month. Data collected were analyzed for effect of the two treatment protocols on the duration of EKC, rate of recovery, and incidence of complications.

RESULTS:

The treatment protocol was significantly better than conventional treatment protocol in achieving cure (P = 0.002) with large effect size. The proportion of cases achieving cure was significantly higher with treatment protocol (64% vs. 11% at 5 days, P < 0.001) by 5 days. There was a significant reduction of the subepithelial infiltrates (SEI) incidence group (10% vs. 57%, P < 0.001). There were no SEI at 1 month in the treatment group (0% vs. 31%).

CONCLUSION:

Treatment protocol used in our study can significantly reduce the severity and duration of EKC. It can prevent chronic keratitis in majority of cases. Since povidone-iodine is nonspecific and virucidal for adenovirus, this therapy can be used for other types of adenoviral conjunctivitis.

Broad-spectrum antiviral activity of the deubiquitinase inhibitor HBX against human adenoviruses

BACKGROUND

Human adenoviral (HAdV) infections are usually mild and self-limited, however, some infections from species A, B, C, D and E, can cause severe illnesses, which have raised public health concerns over the past few years. Current available antiviral therapies have limited efficacy and severe toxicity; therefore, finding new targets for specific anti-adenoviral drug design is urgently needed. Our previous work showed that the small molecule compound, HBX, inhibits HAdV type 5 (species C, HAdV-C5) replication and oncogenic transformation through inhibition of the cellular pro-viral factor ubiquitin-specific protease 7 (USP7). Here, we have tested the ability of HBX to inhibit other HAdV species, as well as different clinical isolates that are the cause of severe infections.

METHODS

We treated HAdV-infected A549 cells with different concentrations of HBX and analysed the antiviral efficacy of the drug by determining the half maximal inhibitory concentration (IC50) necessary to decrease both viral genome copies and virus progeny production at different time points after infection.

RESULTS

In addition to its effect on HAdV-C5, HBX was able to significantly inhibit virus genome replication and progeny release of all adenovirus types tested, with the exception of types 12 and 31, from species A. Of note, clinical isolates were more sensitive to HBX treatment than their prototype strains.

CONCLUSIONS

These results point to HBX as a promising broad-spectrum anti-adenoviral drug, opening new opportunities to prevent severe adenoviral infections and to improve their treatment.

An outbreak of epidemic keratoconjunctivitis caused by human adenovirus type 8 in primary school, southwest China

Background

Two outbreaks of epidemic keratoconjunctivitis (EKC) occurred successively with an interval of 5 days in two primary boarding schools in Weixi Lisu Autonomous County, Diqing, and Tibetan Autonomous Prefecture, Yunnan. The aims of this study were to determine the intensity and characteristics of the outbreaks, as well as the clinical manifestations in the patients, the risk factors for infection and the pathogen responsible for the two outbreaks.

Methods

An outbreak investigation was conducted in two primary schools, and a case-control study including patients from the Weixi County Ethnic Primary School was performed. Relevant specimens were collected according to the case definition, and next-generation sequencing was employed to identify the pathogen. An epidemiological investigation method was used to analyse the related epidemiological characteristics, such as risk factors. The phylogenetic tree was constructed by MEGA 7.0.

Results

A total of 331 acute conjunctivitis cases, including probable cases of EKC, were reported in the two schools, and the attack rates were 30.59% (171/559, 95%CI: 26.76–34.42) and 20.41% (160/784, 95%CI: 17.58–23.24), respectively. Cases occurred in all grades and classes in both schools, and only one staff member in each school presented illness. The epidemics lasted for 54 days and 45 days, respectively. The patients had typical manifestations of EKC, such as acute onset, follicular hyperplasia, pseudomembrane formation, preauricular lymphadenopathy, corneal involvement and blurred vision, and a relatively long disease course (average 9.40 days, longest 23 days and shortest 7 days). The risk factor for infection was close contact with a patient or personal items contaminated by a patient. The pathogen responsible for the outbreaks was HAdV-8. The virus was highly similar to the 2016 HAdV-8 strain from Tibet, China.

Conclusions

This study strongly suggests that HAdV-8 could lead to serious consequences. This is the second report of a HAdV-8-associated EKC outbreak in mainland China. Tibetan HAdV-8 might be circulating in southwest China; therefore, it is necessary to monitor the pathogens causing acute conjunctivitis in this area.

A Review of Next-Generation Sequencing (NGS): Applications to the Diagnosis of Ocular Infectious Diseases

Purpose: To review the value of next-generation sequencing (NGS) in identifying the pathogens which cause ocular infections, thereby facilitating prompt initiation of treatment with an optimal anti-microbial regimen. Both contemporary and futuristic approaches to identifying pathogens in ocular infections are covered in this brief overview. Methods: Review of the peer reviewed literature on conventional and advanced methods as applied to the diagnosis of infectious diseases of the eye. Conclusion: NGS is a novel technology for identifying the pathogens responsible for ocular infections with the potential to improve the accuracy and speed of diagnosis and hastening the selection of the best therapy.

Sialic Acid-Containing Glycans as Cellular Receptors for Ocular Human Adenoviruses: Implications for Tropism and Treatment

Human adenoviruses (HAdV) are the most common cause of ocular infections. Species B human adenovirus type 3 (HAdV-B3) causes pharyngoconjunctival fever (PCF), whereas HAdV-D8, -D37, and -D64 cause epidemic keratoconjunctivitis (EKC). Recently, HAdV-D53, -D54, and -D56 emerged as new EKC-causing agents. HAdV-E4 is associated with both PCF and EKC. We have previously demonstrated that HAdV-D37 uses sialic acid (SA)-containing glycans as cellular receptors on human corneal epithelial (HCE) cells, and the virus interaction with SA is mediated by the knob domain of the viral fiber protein. Here, by means of cell-based assays and using neuraminidase (a SA-cleaving enzyme), we investigated whether ocular HAdVs other than HAdV-D37 also use SA-containing glycans as receptors on HCE cells. We found that HAdV-E4 and -D56 infect HCE cells independent of SAs, whereas HAdV-D53 and -D64 use SAs as cellular receptors. HAdV-D8 and -D54 fiber knobs also bound to cell-surface SAs. Surprisingly, HCE cells were found resistant to HAdV-B3 infection. We also demonstrated that the SA-based molecule i.e., ME0462, designed to bind to SA-binding sites on the HAdV-D37 fiber knob, efficiently prevents binding and infection of several EKC-causing HAdVs. Surface plasmon resonance analysis confirmed a direct interaction between ME0462 and fiber knobs. Altogether, we demonstrate that SA-containing glycans serve as receptors for multiple EKC-causing HAdVs, and, that SA-based compound function as a broad-spectrum antiviral against known and emerging EKC-causing HAdVs.

Decoy Receptor Interactions as Novel Drug Targets against EKC-Causing Human Adenovirus

Epidemic keratoconjunctivitis (EKC) is a severe ocular disease and can lead to visual impairment. Human adenovirus type-37 (HAdV-D37) is one of the major causative agents of EKC and uses sialic acid (SA)-containing glycans as cellular receptors. Currently, there are no approved antivirals available for the treatment of EKC. Recently, we have reported that sulfated glycosaminoglycans (GAGs) bind to HAdV-D37 via the fiber knob (FK) domain of the viral fiber protein and function as decoy receptors. Based on this finding, we speculated that GAG-mimetics may act as artificial decoy receptors and inhibit HAdV-D37 infection. Repurposing of approved drugs to identify new antivirals has drawn great attention in recent years. Here, we report the antiviral effect of suramin, a WHO-approved drug and a widely known GAG-mimetic, against HAdV-D37. Commercially available suramin analogs also show antiviral effects against HAdV-D37. We demonstrate that suramin exerts its antiviral activity by inhibiting the attachment of HAdV-D37 to cells. We also reveal that the antiviral effect of suramin is HAdV species-specific. Collectively, in this proof of concept study, we demonstrate for the first time that virus binding to a decoy receptor constitutes a novel and an unexplored target for antiviral drug development.

Seroepidemiological investigation of HAdV-4 infection among healthy adults in China and in Sierra Leone, West Africa

An apparent increase in the frequency of human adenovirus type 4 (HAdV-4) infections among general populations has been observed over the past 10 years. However, available epidemiological data that may reflect previous viral circulation and assist in predicting potential outbreaks are sparse, particularly in mainland China and Africa. In this study, a convenient neutralization assay for use in the surveillance of historical HAdV-4 infections was established based on a recombinant luciferase-expressing virus. Subsequently, the neutralizing antibodies (nAbs) of 1013 healthy adult serum samples from China and Sierra Leone were evaluated. Our results showed that over 50% of the participants from China and nearly 70% of donors from Sierra Leone had detectable nAbs against HAdV-4 despite the few infection cases officially reported in these regions. Furthermore, the prevalence of nAbs to HAdV-4 is lower than that to HAdV-5, and both varied by geographic location. In addition, the seropositive rates of both HAdV-4 and HAdV-5 nAbs increased with age. However, the nAbs stimulated by HAdV-4 remained stable at low (≤200) levels among the different age groups, whereas moderate (201–1000) or high (>1000) nAb levels were produced by HAdV-5 and tended to decrease with age. These results elucidate the human humoral immune response against HAdV-4 and revealed that this virus may be an underestimated causative agent of respiratory disease among adults in China and West Africa, demonstrating the importance of HAdV-4 surveillance and providing useful insights for the future development of HAdV-4-based vaccines.

Molecular epidemiology of circulating human adenovirus types in acute conjunctivitis cases in Chandigarh, North India

Human adenovirus (HAdV) is a major cause of viral conjunctivitis. The various serotypes implicated in the causation are 3, 4, 8, 19 and 37. The present study aimed to know the circulating types of HAdV causing acute conjunctivitis in North India. A total of 23 conjunctival swabs were collected from patients with clinically suspected acute viral conjunctivitis during 2014-2015. The HAdV was implicated in the etiology in 65.2% of cases. The sequencing of representative samples using hexon gene suggests the presence of serotype 8 and 4. The serotype eight sequences showed 99%-100% similarity with other Indian strains. The phylogenetic analysis showed that the current circulating serotypes, responsible for conjunctivitis, belonged to epidemic keratoconjunctivitis strains.

A recombinant trivalent vaccine candidate against human adenovirus types 3, 7, and 55

Human adenoviruses types 3 (HAdV-3), 7 (HAdV-7) and 55 (HAdV-55) are major pathogens of acute respiratory infections (ARI) in children and adults. More than one type of HAdV can infect patients simultaneously, and the infections are sometimes fatal. However, there is currently no vaccine approved for general use in children and adults. Thus, development of a multivalent HAdV vaccine to combat HAdV infection becomes imperative. In this study, we constructed a new recombinant trivalent human adenovirus vaccine (rAdMHE3-h55), which expresses the hexon protein of HAdV-55 in the E3 region of rAdMHE3, a previously prepared bivalent vaccine candidate against HAdV-3 and HAdV-7. The results of in vitro neutralization assays indicate that rAdMHE3-h55 can induce the production of neutralizing antibodies against HAdV-3, HAdV-7, and HAdV-55 in mice. Furthermore, immunization with the recombinant trivalent vaccine candidate completely protected the mice challenged with HAdV-3, HAdV-7, orHAdV-55, respectively, showing lower lung viral loads and less lung Pathological changes was compared with those in unvaccinated mice. The current findings contribute to the development of a new adenovirus vaccine candidate and also advance this construction method for the generation of recombinant adenovirus vaccines. In conclusion, our recombinant trivalent vaccine rAdMHE3-h55 can provides protection against challenge with HAdV-3, HAdV-7, or HAdV-55 in mice. Future work of optimizing this vaccine candidate may lead to a more effective way of preventing respiratory diseases caused by common human adenoviruses.