Multiple outbreaks of acute hemorrhagic conjunctivitis due to a variant of coxsackievirus A24: Guangdong, China, 2007

[Viral and chlamydial conjunctivitis]

Viral conjunctivitis is the most common type of conjunctivitis. It is contagious and is predominantly seen as adenovirus-related conjunctivitis and keratoconjunctivitis (ADV). These infections are the most frequent ocular surface infections and can lead to conjunctival scarring and corneal opacities. Other types of viral conjunctivitis are often secondary to systemic infection and typically resolve spontaneously. Chlamydial conjunctivitis, on the other hand, is dominated by trachoma, which remains endemic in 42 countries and is still the leading cause of infectious blindness worldwide. In industrialized countries, chlamydia can also cause neonatal conjunctivitis and sometimes chronic conjunctivitis, occasionally associated with sexually transmitted diseases. This comprehensive review provides clinicians with essential microbiological, epidemiological, clinical, and therapeutic data on these two major groups of infectious conjunctivitis.

An Outbreak of Acute Hemorrhagic Conjunctivitis Caused by Coxsackievirus A24 in Eastern Uttar Pradesh, India 2023

INTRODUCTION

Acute hemorrhagic conjunctivitis (AHC) outbreaks are caused mostly by viruses. During July-August 2023, there was a sudden spike in acute hemorrhage conjunctivitis cases in Eastern Uttar Pradesh, India. To identify the etiological and gain molecular epidemiology of the agent, the study was conducted.

METHODOLOGY

Conjunctival swabs were collected from patients (n = 128) with presumed acute hemorrhage conjunctivitis visiting two tertiary care hospitals.

RESULTS

Enteroviruses infection was identified in 96 (75%) patients. In these patients, coxsackievirus A24 (CV-A24) infection was further confirmed by targeting the genetic regions of 3C protease and VP1. Furthermore, the study established the outbreak was caused by the genotype IV of CV-A24 with the highest genetic similarity with CV-A24 reported from Northeast India, China, and Pakistan circulating during the same period. The comparison of our study sequences with earlier Indian outbreak strains (2007) revealed four amino acid substitutions at the 3C region ("S21N," "V30I," "S66I," and "V75I") and three non-synonymous mutations at the VP1 region ("L16I," "P21S," and "N301D").

CONCLUSION

The study findings revealed that the AHC outbreak was caused by genotype IV of CV-A24 in this region. Molecular identification accompanied by phylogenetic analysis will be useful in studying the enterovirus epidemiology associated with AHC outbreaks.

Epidemiology of Enterovirus Genotypes in Association with Human Diseases

Enteroviruses (EVs) are well-known causes of a wide range of infectious diseases in infants and young children, ranging from mild illnesses to severe conditions, depending on the virus genotypes and the host's immunity. Recent advances in molecular surveillance and genotyping tools have identified over 116 different human EV genotypes from various types of clinical samples. However, the current knowledge about most of these genotypes, except for those of well-known genotypes like EV-A71 and EV-D68, is still limited due to a lack of comprehensive EV surveillance systems. This limited information makes it difficult to understand the true burden of EV-related diseases globally. Furthermore, the specific EV genotype associated with diseases varies according to country, population group, and study period. The same genotype can exhibit different epidemiological features in different areas. By integrating the data from established EV surveillance systems in the USA, Europe, Japan, and China, in combination with other EV infection studies, we can elaborate a better understanding of the distribution of prevalent EV genotypes and the diseases associated with EV. This review analyzed the data from various EV surveillance databases and explored the EV seroprevalence and the association of specific EV genotypes with human diseases.

Molecular characterization of coxsackievirus A24 variants isolated from an outbreak of acute hemorrhagic conjunctivitis

PURPOSE

Acute Hemorrhagic conjunctivitis (AHC) is associated with CVA24v. Recently there was a severe outbreak of conjunctivitis in months of July and August 2023 in India. This study emphasizes the identification of the distinct mutations in the CVA24v strains, which were isolated during the AHC outbreak and could have potentially played a role in the high transmission of AHC in India during the 2023 outbreak.

METHODS

A total of 71 conjunctivitis patients aged 1-75 years comprising 47 males and 24 females who attended Ophthalmology department of a tertiary care hospital of easternIndia were studied.RNA was extracted from all conjunctival swab samples and converted into cDNA. Subsequently, the viral 5' UTR was amplified and the PCR positive samples were subjected to sequencing. The newly isolated viral 5' UTR sequences were aligned with other worldwide sequences using the Clustal W tool to conduct mutational analysis. A phylogenetic tree was built using the MEGA software for viral genotype identification.

RESULTS

All of the current outbreak strains belonged to genotype IV of CVA24v. The present outbreak strains formed a distinct clade in the phylogenetic tree and were different from previously reported Indian strains. Two persistent mutations, specifically in domain IV (T213C) and domain V (C475T), were exclusively detected within the internal ribosome entry site (IRES) of the 5' UTR of the current strains causing the outbreak. These two alterations have previously been shown to impact the virulence of another enterovirus (CV B3), but they have not been described in CVA24v until now.

CONCLUSION

Finding of the present study highlights the possibility and the significance of the aforementioned two mutations in enhancing the transmissibility of the newer CVA24v strains. Hence, these two distinct mutations should be investigated further for developing antiviral therapies to combat future AHC outbreaks associated with CVA24v.

Prevalence of adenoviruses as ocular disease causatives in Saudi Arabia

Although Human Adenoviruses outbreaks are rare, there still could be a potential chance for those viruses to mutate and spread quickly in human populations with severe public health and socioeconomic consequences. Outbreaks often spread fairly quickly with considerable morbidity/mortality. Saudi Arabia's geopolitical and religious significance bring with it, millions of pilgrims, and tourists yearly. This presents a significant potential for HAdVs epidemics. This review shows that even with the mushrooming serotypes and genotypes, the scholarly knowledge on the nature, structure, transmission, and management of HAdVs is already well-established. Significant research is ongoing on pharmacological interventions, which, presently remain speculative and lacking in effectiveness. This review similarly uncovers a shortage of literature, both recent and dated, on epidemic keratoconjunctivitis in either Saudi Arabia or the Middle East.

Epidemiological trends and sociodemographic factors associated with acute hemorrhagic conjunctivitis in mainland China from 2004 to 2018

BACKGROUND

Acute hemorrhagic conjunctivitis (AHC) is classified as a class C notifiable infectious disease in China and poses a great threat to public health. This study aimed to investigate the epidemiological trends and hotspots of AHC in mainland China. Sociodemographic factors that could contribute to early warning of AHC were further explored.

METHODS

Yearly and monthly incidences of acute hemorrhagic conjunctivitis by date and region from 2004 to 2018 were extracted from the Data Center of China Public Health Science. Joinpoint regression and spatial autocorrelation analysis were performed to explore the epidemiological trends and hotspots of AHC. A generalized linear model was then applied to explore the relationship between sociodemographic factors and AHC incidence.

RESULTS

The average annual AHC incidence was 3.58/100,000 in mainland China. The first-level spatial and temporal aggregation areas were distributed in Guangxi, Hainan, Guangdong, Guizhou, Hunan, Jiangxi, Fujian, Chongqing, Hubei, Anhui, and Zhejiang, with gathering times from 2010/1/1 to 2010/12/31 (RR = 20.13, LLR = 474,522.89, P < 0.01). After 2010, the AHC incidence was stable (APC = - 8.37, 95% CI: - 23.02-9.06). However, it was significantly increased in low- and middle-income provinces (AAPC = 10.65, 95% CI: 0.62-21.68, AAPC = 11.94, 95% CI: 0.62-24.53). The peak of AHC occurred during the August to October period. Children who age 0-3 years are identified as high-risk group with AHC incidence significantly increased (APC = 31.54, 95% CI: 0.27-72.56). Birth rate, population ages 0-14 (% of total population), passenger traffic, and urban population (% of total population) were positively associated with the AHC incidence, while per capita gross domestic product was negatively associated with the AHC incidence.

CONCLUSION

Overall, the AHC incidence was stable after 2010 in China, but it was significantly increased in low- and middle-income provinces. Regions with a high birth rate, population ages 0-14 (% of the total population), passenger traffic, urban population (% of the total population) and low per capita gross domestic product are at high risk of incidences of AHC. In the future, public health policy and resource priority for AHC in regions with these characteristics are necessary.

Isothermal nucleic acid amplification technology for rapid detection of virus

While the research field and industrial market of in vitro diagnosis (IVD) thrived during and post the COVID-19 pandemic, the development of isothermal nucleic acid amplification test (INAAT) based rapid diagnosis was engendered in a global wised large measure as a problem-solving exercise. This review systematically analyzed the recent advances of INAAT strategies with practical case for the real-world scenario virus detection applications. With the qualities that make INAAT systems useful for making diagnosis relevant decisions, the key performance indicators and the cost-effectiveness of enzyme-assisted methods and enzyme-free methods were compared. The modularity of nucleic acid amplification reactions that can lead to thresholding signal amplifications using INAAT reagents and their methodology design were examined, alongside the potential application with rapid test platform/device integration. Given that clinical practitioners are, by and large, unaware of many the isothermal nucleic acid test advances. This review could bridge the arcane research field of different INAAT systems and signal output modalities with end-users in clinic when choosing suitable test kits and/or methods for rapid virus detection.

Practical Guidance for Clinical Microbiology Laboratories: Diagnosis of Ocular Infections

The variety and complexity of ocular infections have increased significantly in the last decade since the publication of Cumitech 13B, Laboratory Diagnosis of Ocular Infections (L. D. Gray, P. H. Gilligan, and W. C. Fowler, Cumitech 13B, Laboratory Diagnosis of Ocular Infections, 2010). The purpose of this practical guidance document is to review, for individuals working in clinical microbiology laboratories, current tools used in the laboratory diagnosis of ocular infections. This document begins by describing the complex, delicate anatomy of the eye, which often leads to limitations in specimen quantity, requiring a close working bond between laboratorians and ophthalmologists to ensure high-quality diagnostic care. Descriptions are provided of common ocular infections in developed nations and neglected ocular infections seen in developing nations. Subsequently, preanalytic, analytic, and postanalytic aspects of laboratory diagnosis and antimicrobial susceptibility testing are explored in depth.

An outbreak of acute haemorrhagic conjunctivitis associated with coxsackievirus A24 variant in The Gambia, West Africa

OBJECTIVE

An outbreak of acute haemorrhagic conjunctivitis occurred in The Gambia, West Africa in 2011. Affected individuals presented with conjunctival haemorrhages, swelling and ocular discharge. In an effort to identify a causative agent of the disease, ocular swabs were taken from patients during the acute and convalescent phases. Total RNA was extracted from all samples and reverse-transcriptase PCR performed using primers specific for all enteroviruses. Resulting amplicons were sequenced and data compared to known sequences using the BLAST algorithm.

RESULTS

Forty-eight swabs were included in the analysis. Of these, 21 acute and 9 convalescent swabs (65% of the total) gave positive PCR results. Sequence analysis of the resulting amplicons indicated 99% sequence identity with coxsackievirus A24 variant identified during independent outbreaks of acute haemorrhagic conjunctivitis around the world and suggest the Gambian outbreak was due to this virus.

Molecular epidemiology of acute hemorrhagic conjunctivitis caused by coxsackie A type 24 variant in China, 2004-2014

To understand control interventions, the molecular epidemiology of acute hemorrhagic conjunctivitis (AHC) was investigated from 2004 to 2014.A total of 613,485 AHC cases (annualized cases 55,771) with two deaths were included. Our findings showed that AHC was reported in all provinces, predominantly in Southern and Eastern China. The incidence rates were highest in 2007 (5.65/100,000) and 2010 (21.78/100,000) respectively. A clear seasonal pattern was identified with a peak from August to October. AHC cases occurred in all age groups; however, five to 14 years was the predominant group [23.06%, 133, 510/578,909]. The median age was 24 years (one month~97 years). The median duration from onset to diagnosis was 1.5 days, and there was no difference between the <15, 15~60 and >60-year-old patients [p = 0.0653]. The phylogenetic analysis of 100 nonstructural proteins (3C) and 84 structural proteins (VP1) revealed that AHC outbreaks were caused by Coxsackievirus A24 variant. Genotypes G4-c5a, G4-c5b, and G4-c3 co-circulated with both temporal and geographical overlaps. In conclusion, despite the overall steady decline in the number of AHC cases since the peak in 2010, it still remains a serious public health problem in Southern and Eastern China that targets on the school aged children under 15 years old.

Complete genome analysis of coxsackievirus A24 isolated in Yunnan, China, in 2013

Human coxsackievirus A24 (CVA24) belongs to the species Enterovirus C, and variants of this virus frequently cause acute hemorrhagic conjunctivitis (AHC). The complete genome of the K282/YN/CHN/2013 strain, isolated from a healthy child in Yunnan, China, in 2013, is reported here for the first time. The strain showed 80.0 % and 79.9 % nucleotide sequence identity to CVA24 prototype strain Joseph and CVA24 variant prototype EH24, respectively. The K282/YN/CHN/2013 strain belongs to the CVA24 serotype. Twelve amino acid differences, most of which are in structural regions, were found between the CVA24 and CVA24v strains. In the whole-length genome sequence, only the structural region of K282/YN/CHN/2013 was similar to that of the CVA24 strains; the other genome regions were more similar to those of other members of the species Enterovirus C. Recombination analysis showed evidence of recombination with other viruses of the same species.

Virological and epidemiological analysis of coxsackievirus A24 variant epidemic of acute hemorrhagic conjunctivitis in Okinawa, Japan, in 2011

BACKGROUND

Acute hemorrhagic conjunctivitis (AHC) is a highly contagious enterovirus infection of the conjunctiva and cornea. Coxsackievirus A24 variant (CA24v) is one of its etiological agents. We report a clinical, epidemiological, and virological analysis of a large epidemic of AHC that occurred from May to September, 2011, in Okinawa, Japan.

METHODS

Clinical and epidemic aspects were evaluated for 435 AHC patients (348 bilateral and 87 unilateral, 783 eyes). Virological studies were carried out on nine isolates from ten patients. Virus isolation and direct detection of the enterovirus genome by the reverse transcription polymerase chain reaction method and complete nucleotide sequencing of the VP1 gene and phylogeny-based classification using the VP4 sequences were carried out.

RESULTS

The 11-15-year age group comprised the highest (62.0%) proportion of cases among all age groups. Conjunctival hyperemia was present in all patients, and subconjunctival hemorrhage, superficial punctate keratitis, and preauricular lymphadenopathy were present in 25.4%, 10.3%, and 7.8% of eyes, respectively. CA24v was isolated from the epidemic strain, and phylogenetic analysis based on a fragment of the VP1 gene showed 96%-97% identity between the current strain and the recent China/GD01/2010 strain.

CONCLUSION

These findings demonstrate that the clinical and epidemiological features of AHC observed in this study were similar to those of the past epidemic in the same region. It should be noted that sequential outbreaks of AHC due to CA24v might occur in the same location after a considerable period of time, and public health precautions are necessary to control this explosive epidemic.

Infection Prevention and Control in Residential Facilities for Pediatric Patients and Their Families

The Society for Healthcare Epidemiology of America (SHEA) guideline “Infection Prevention and Control in Residential Facilities for Pediatric Patients and Their Families” is the first infection prevention and control (IPC) guideline to address preventing transmission of infectious agents in “home away from home” residential settings, of which the Ronald McDonald Houses (RMHs) serve as a prototype. These types of facilities provide support services, including overnight lodging, for ill and injured children and their families. Food preparation occurs in common areas, and cleaning of rooms or apartments is performed by the occupants during their stay and before departure. Pediatric patients are frequent guests of the family-centered facilities while receiving or recovering from specialized medical therapy. Examples of high-risk populations served in these facilities include families of patients with cancer, recipients of stem cell or solid organ transplants, surgical and/or very-low-birthweight infants who receive care in neonatal intensive care units (NICUs), those with cystic fibrosis, and women with high-risk pregnancies awaiting delivery in a nearby medical center. Such facilities are located worldwide and vary in their physical structure and the predominant population served.

Genetic characteristics of the coxsackievirus A24 variant causing outbreaks of acute hemorrhagic conjunctivitis in Jiangsu, China, 2010

During September 2010, an outbreak of acute hemorrhagic conjunctivitis reemerged in Jiangsu, three years after the nationwide epidemic in China in 2007. In total, 2409 cases were reported, 2118 of which were reported in September; 79.8% of those affected were students or teachers, with a median age of 16 years. To identify and demonstrate the genetic characteristics of the etiological agent, 52 conjunctival swabs were randomly collected from four different cities. After detection and isolation, 43 patients were positive for coxsackievirus A24 variant according to PCR and 20 according to culture isolation. Neither adenovirus nor EV70 was detected. A phylogenetic study of the complete 3Cpro and VP1 regions showed that the Jiangsu isolates clustered into a new lineage, GIV-C5, with two uniform amino-acid mutations that distinguished them from all previous strains. Another new cluster, GIV-C4, formed by Indian isolates from 2007 and Brazilian isolates from 2009, was also identified in this study. Interestingly, our isolates shared greatest homology with the GIV-C4 strains, not with the isolates that were responsible for the nationwide acute hemorrhagic conjunctivitis epidemic in China in 2007. Although all our isolates were closely related, they could be differentiated into two subclusters within GIV-C5. In conclusion, our study suggests that a new cluster of coxsackievirus A24 variant that had already evolved into diverse strains was associated with the acute hemorrhagic conjunctivitis outbreaks in Jiangsu in September 2010. These viruses might have originated from the virus isolated in India in 2007, rather than from the epidemic strains isolated in China in 2007.

Molecular identification and phylogenetic study of coxsackievirus A24 variant isolated from an outbreak of acute hemorrhagic conjunctivitis in India in 2010

An outbreak of acute hemorrhagic conjunctivitis (AHC) occured in India between August and October 2010. Molecular typing by RT-PCR and sequencing of a partial VP1 region identified coxsackievirus A24 variant (CV A24v) as the serotype involved in this outbreak. Phylogenetic analysis based on the VP1 and 3C genes revealed that CV A24v strains associated with the 2010 AHC outbreak in India were genetically similar to strains from Central and South America that caused outbreaks of AHC in Cuba between 2008 and 2009 and Brazil in 2009. The result shows that the Indian strain of CV A24v may be responsible for the recent AHC outbreak in Marseille, France, in 2012.

Complete genome sequence of two coxsackievirus A1 strains that were cytotoxic to human rhabdomyosarcoma cells

Coxsackievirus A1 (CVA1) belongs to human enterovirus species C within the family Picornaviridae, order Picornavirales. Two Chinese CVA1 isolates, HT-THLH02F/XJ/CHN/2011 and KS-ZPH01F/XJ/CHN/2011, were isolated from stool specimens of two healthy children in the Xinjiang Uygur autonomous region of China. They were found to elicit cytopathic effects in a human rhabdomyosarcoma cell line, and complete genome sequences of these two CVA1 isolates revealed that natural intertypic recombination events occurred between CVA1 and CVA22.

Phylogenetic and molecular characterization of coxsackievirus A24 variant isolates from a 2010 acute hemorrhagic conjunctivitis outbreak in Guangdong, China

BACKGROUND

Acute hemorrhagic conjunctivitis is a common disease in China. As a notifiable disease, cases are registered by ophthalmologists on the AHC surveillance system. An AHC outbreak caused by CA24v was observed in Guangdong Province in 2007 by the National Disease Supervision Information Management System. Three years later, a larger outbreak occurred in Guangdong during the August-October period (2010). To characterize the outbreak and compare the genetic diversity of CA24v, which was determined to be the cause of the outbreak, the epidemiology and the molecular characterization of CA24v were analyzed in this study.

RESULTS

A total of 69,635 cases were reported in the outbreak. 73.5% of index cases originated from students, children in kindergarten and factory workers, with the ≦ 9 age group at the highest risk. The male to female ratio was 1.84:1 among 0-19 years. 56 conjunctival swabs were collected to identify the causative agent from five cities with the AHC outbreak. 30 virus strains were isolated, and two of the genomes had the highest identity values (95.8%) with CA24v genomes. Four CA24v genotypes were identified by phylogenetic analysis for the VP1 and 3C regions. CA24v which caused the outbreak belonged to genotype IV. Furthermore, full nucleotide sequences for four representative isolates in 2010 and 2007 were determined and compared. 20 aa mutations, two nt insertions and one nt deletion were observed in the open reading frame, with 5'- and 3'- UTR respectively between them.

CONCLUSIONS

CA24v was determined to be the pathogen causing the outbreak and belongs to genotype IV. VP1 is more informative than 3C(Pro) for describing molecular epidemiology and we hypothesize that accumulative mutations may have promoted the outbreak.

Isolation of Coxsackievirus A24 variant from patients with hemorrhagic conjunctivitis in Cuba, 2008-2009

BACKGROUND

An outbreak of acute hemorrhagic conjunctivitis occurred in Cuba in 2008 and 2009.

OBJECTIVE

To determinate the etiological agent associated with the Cuban outbreaks of acute hemorrhagic conjunctivitis during 2008 and 2009.

STUDY DESIGN

Conjunctival swabs and/or faecal samples from 382 patients with clinical diagnosis suggestive of acute hemorrhagic conjunctivitis were subject to viral culture in HEp-2 human laryngeal epidermoid carcinoma cells. Positive samples were identified by a specific Coxsackievirus A24 variant PCR and the 3C protease region of 16 isolates was sequenced for phylogenetic analysis.

RESULTS

Enterovirus cytopathic effect was observed in 138 cases (36%). A higher percent of CA24v was recovered from faecal samples, 19 out of 45 cases (42.2%), than from conjunctival swabs, 127 out of 355 samples (35.8%). All isolates were identified as Coxsackievirus A24 variant. Phylogenetic analysis revealed that 2008 and 2009 Cuban outbreaks were caused by the same virus strains and that isolates were closely related to those from Taiwan (2006-2007), China (2007-2008) and Singapore (2005) with a bootstrap value of 71%.

CONCLUSIONS

Outbreaks of acute hemorrhagic conjunctivitis occurred in Cuba in 2008 and 2009 were caused by Coxsackievirus A24 variant. The faecal-oral route is another mode of transmission of CA24v in the acute hemorrhagic conjunctivitis outbreaks. Phylogenetic analysis of Cuban CA24v strains involved in an acute hemorrhagic conjunctivitis outbreak in 2008 and 2009 confirms a new introduction of the CA24 variant into the Americas from South-east Asia.

Molecular characterization and phylogenetic study of coxsackievirus A24v causing outbreaks of acute hemorrhagic conjunctivitis (AHC) in Brazil

BACKGROUND

Coxsackievirus A24 variant (CA24v) is the most prevalent viral pathogen associated with acute hemorrhagic conjunctivitis (AHC) outbreaks. Sixteen years after its first outbreak in Brazil, this agent reemerged in 2003 in Brazil, spread to nearly all states and caused outbreaks until 2005. In 2009, a new outbreak occurred in the northeast region of the country. In this study, we performed a viral isolation in cell culture and characterized clinical samples collected from patients presenting symptoms during the outbreak of 2005 in Vitória, Espírito Santo State (ES) and the outbreak of 2009 in Recife, Pernambuco State (PE). We also performed a phylogenetic analysis of worldwide strains and all meaningful Brazilian isolates since 2003.

METHODS AND FINDINGS

Sterile cotton swabs were used to collect eye discharges, and all 210 clinical samples were used to inoculate cell cultures. Cytopathic effects in HEp-2 cells were seen in 58 of 180 (32%) samples from Vitória and 3 of 30 (10%) samples from Recife. Phylogenetic analysis based on a fragment of the VP1 and 3C gene revealed that the CA24v causing outbreaks in Brazil during the years 2003, 2004 and 2005 evolved from Asian isolates that had caused the South Korean outbreak of AHC during the summer of 2002. However, the 2009 outbreak of AHC in Pernambuco was originated from the reintroduction of a new CA24v strain that was circulating during 2007 in Asia, where CA24v outbreaks has been continuously reported since 1970.

CONCLUSIONS

This study is the first phylogenetic analysis of AHC outbreaks caused by CA24v in Brazil. The results showed that Asian strains of CA24v were responsible for the outbreaks since 1987 and were independently introduced to Brazil in 2003 and 2009. Phylogenetic analysis of complete VP1 gene is a useful tool for studying the epidemiology of enteroviruses associated with outbreaks.

[Enteroviruses responsible for acute hemorrhagic conjunctivitis]

Acute hemorrhagic conjunctivitis (AHC) is an epidemic form of highly contagious conjunctivitis, characterized by conjunctival hemorrhages. The first AHC outbreak was described in 1969 in Ghana, West Africa, and was called Apollo disease, from the Apollo landing on the moon. This outbreak was caused by Enterovirus 70 (EV70) together with a Coxsackievirus A24 (CVA24v) variant, which are the major etiological agents involved in AHC outbreaks worldwide. AHC is known to be directly transmitted by close person-to-person contact or indirectly through soiled ophthalmological materials or unsafe recreational water. Recently, a possible airborne virus spread was suggested which could explain the high transmission rate of the disease. In the absence of a specific antiviral therapy, a rapid diagnosis of the causative agent is required to distinguish AHC due to enteroviruses from other ocular infectious diseases, for there are active drugs, or to quickly implement proper public health measures to limit the extension of the outbreak. However, virus identification remains difficult and time-consuming. Moreover, virological diagnosis is difficult to implement in developing countries where AHC has recently become a major problem for public health.

Outbreak of acute hemorrhagic conjunctivitis in Yunnan, People's Republic of China, 2007

An outbreak of acute hemorrhagic conjunctivitis (AHC) occurred in Yunnan Province, China between August and September in 2007. A total of 3,597 cases were officially reported and the incidence rate reached 1390.94/100,000. Descriptive epidemiological analysis of the outbreak was conducted using the data from National Disease Supervision Information Management System (NDSIMS). To determine the causative agent for this outbreak and to analyze their genetic features, 30 conjunctival swabs and 19 paired serum specimens of acute and convalescent phase were collected from 30 patients with AHC, and viral isolation, molecular typing, antibody assay and phylogenetic analysis were performed.

11 virus strains were isolated from 30 conjunctival swabs. Amplification and sequencing of the VP4 region of these strains identified that coxsackievirus A24 variant (CA24v) could be the causative agent of the AHC outbreak and this was further confirmed by subsequent virus neutralizing antibody test on 19 paired serum specimens. Phylogenetic analysis based on the 3C regions showed that the Yunnan CA24v strains belonged to Group 3 and clustered with the strains isolated from worldwide AHC outbreaks after 2002. Phylogenetic analysis based on the partial VP1 revealed that the Yunnan strains differed from the strains isolated from AHC outbreak in Guangdong of China in 2007 with 2.8 - 3.0% nucleotide divergence, suggesting that two different lineages of CA24v caused the independent AHC outbreaks in Yunnan and Guangdong, respectively.

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.

Molecular epidemiology of coxsackie A type 24 variant in Taiwan, 2000-2007

BACKGROUND

Epidemics of acute hemorrhagic conjunctivitis (AHC) caused by a coxsackievirus A24 variant (CA24v) appeared in Taiwan in 2000-2002 and again in 2006-2007.

OBJECTIVE

To analyze the molecular epidemiology of CA24v in recent outbreaks in Taiwan.

STUDY DESIGN

A 510bp fragment of 3C(pro) region was analyzed in 30 CA24v isolates during 2000-2007. Phylogenetic tree was constructed along with 130 CA24v isolates available from the GenBank. Moreover, the 235bp of 3'VP1 region was similarly analyzed in 15 randomly selected strains isolated during 1985-2007. Phylogenetic dendrogram was constructed for the 3'VP1 region in 105 CA24v strains worldwide. Genetic distances were calculated using Kimura 2-parameter model, and phylogenetic trees were constructed by neighbor-joining method.

RESULTS

The 3C(pro) dendrogram depicted genotype IV (GIV), a new genotype that can be further divided into three clusters (C1-C3). The 2000-2002 outbreaks were caused by genotype IV-cluster 1 (GIV-C1) and GIV-C2. Strains isolated in the 2006-2007 outbreak belong to GIV-C3, also in the same cluster as Singapore strains from 2005. Analysis on 3'VP1 revealed only GI, GIII and GIV in line with the classification in 3C(pro) dendrogram. All genotype IV strains were also divided into three clusters, though the GIV-C 2' were isolated from broader geographic areas and over a longer period of time.

CONCLUSIONS

Analysis of the 3C(pro) region is more insightful than the 3'VP1 region in the molecular epidemiology of CA24v. The 3C(pro) dendrogram accurately and chronologically identified all stains involved in the worldwide outbreaks.