Coxsackievirus A16 Research Articles

An outbreak of acute hemorrhagic conjunctivitis due to Coxsackievirus A24 in a residential school, Naharlagun, Arunachal Pradesh: July 2023

PurposeAn acute conjunctivitis outbreak was investigated at a residential school in Naharlagun, Arunachal Pradesh, Northeast India, in July 2023. We aimed to identify the etiological agent and assess any complications in follow-up cases. MethodsWe used a structured questionnaire to record clinical findings and followed up with cases one-month post-conjunctivitis. Sixty-one cases were examined and eight conjunctival and oropharyngeal swab samples were collected after obtaining informed consent from guardians/school authorities. We screened for 33 viral and bacterial pathogens using an IVD-approved Real-time PCR assay. Further, the samples were subjected to nucleic acid sequencing. ResultsAmong 465 screened students and staff, 80 individuals (approximately 17.2%) showed acute hemorrhagic conjunctivitis symptoms among which 61 cases were available for clinical examination. We identified the Enterovirus responsible by targeted sequencing using next-generation sequencing. The etiological agent was found to be Coxsackievirus A24, a member of Enterovirus C, in seven out of eight samples subjected to sequencing. Common symptoms included conjunctival hyperemia and foreign body sensation (100%), bilateral eye involvement (73.8%), eye pain (70%), watery discharge (49.2%), and eyelid swelling (38%). Only 6.5% had purulent discharge. Most cases resolved within 5-6 days, with only 9.8% reporting abdominal symptoms post-conjunctivitis. No serious complications occurred within one month. Throat swabs aided in diagnosing enterovirus infections alongside eye swabs. ConclusionsThe outbreak of acute conjunctivitis was caused by Coxsackievirus A24, a member of Enterovirus C. Cases resolved spontaneously within 6-7 days, with no severe complications. Collecting oropharyngeal swabs alongside conjunctival swabs could improve enteroviral conjunctivitis diagnosis.

Integration of HiBiT into enteroviruses: A universal tool for advancing enterovirus virology research

The utilization of enteroviruses engineered with reporter genes serves as a valuable tool for advancing our understanding of enterovirus biology and its applications, enabling the development of effective therapeutic and preventive strategies. In this study, our initial attempts to introduce a NanoLuc luciferase (NLuc) reporter gene into recombinant enteroviruses were unsuccessful in rescuing viable progenies. We hypothesized that the size of the inserted tag might be a determining factor in the rescue of the virus. Therefore, we inserted the 11-amino-acid HiBiT tag into the genomes of enterovirus A71 (EV-A71), coxsackievirus A10 (CVA10), coxsackievirus A7 (CVA7), coxsackievirus A16 (CVA16), namely EV-A71-HiBiT, CVA16-HiBiT, CVA10-HiBiT, CVA7-HiBiT, and observed that the HiBiT-tagged viruses exhibited remarkably high rescue efficiency. Notably, the HiBiT-tagged enteroviruses displayed comparable characteristics to the wild-type viruses. A direct comparison between CVA16-NLuc and CVA16-HiBiT recombinant viruses revealed that the tiny HiBiT insertion had minimal impact on virus infectivity and replication kinetics. Moreover, these HiBiT-tagged enteroviruses demonstrated high genetic stability in different cell lines over multiple passages. In addition, the HiBiT-tagged viruses were successfully tested in antiviral drug assays, and the sensitivity of the viruses to drugs was not affected by the HiBiT tag. Ultimately, our findings provide definitive evidence that the integration of HiBiT into enteroviruses presents a universal, convenient, and invaluable method for advancing research in the realm of enterovirus virology. Furthermore, HiBiT-tagged enteroviruses exhibit great potential for diverse applications, including the development of antivirals and the elucidation of viral infection mechanisms.

Emergence of Recombinant Subclade D3/Y in Coxsackievirus A6 Strains in Hand-Foot-and-Mouth Disease (HFMD) Outbreak in India, 2022.

Coxsackievirus-A6 (CV-A6) is responsible for more severe dermatological manifestations compared to other enteroviruses such as CV-A10, CV-A16, and EV-A71, causing HFMD in children and adults. Between 2005 and 2007, the recombinant subclade D3/RF-A started to expand globally, and a CV-A6 pandemic started. The study aimed to conduct whole-genome sequencing (WGS) of an isolated CV-A6 strain from currently circulating HFMD cases from India in 2022. Gene-specific RT-PCR and sequencing were used to perform molecular characterization of the isolated virus. Confirmation of these isolates was also performed by transmission electron microscopy and WGS. Among eleven positive clinical enterovirus specimens, eight CV-A6 strains were successfully isolated in the RD cell line. Isolates confirmed the presence of the CV-A6 strain based on VP1 and VP2 gene-specific RT-PCR. Sequences of isolates were clustered and identified as the novel CV-A6 strain of the D3/Y sub-genotype in India. The studies revealed that the D3/Y sub-genotype is being introduced into Indian circulation. The predicted putative functional loops found in VP1 of CV-A6 showed that the nucleotide sequences of the amino acid were a remarkably conserved loop prediction compatible with neutralizing linear epitopes. Therefore, this strain represents a potential candidate for vaccine development and antiviral studies.

Age-time-specific transmission of hand-foot-and-mouth disease enterovirus serotypes in Vietnam: A catalytic model with maternal immunity

Hand, foot and mouth disease (HFMD) is highly prevalent in the Asia Pacific region, particularly in Vietnam. To develop effective interventions and efficient vaccination programs, we inferred the age-time-specific transmission patterns of HFMD serotypes enterovirus A71 (EV-A71), coxsackievirus A6 (CV-A6), coxsackievirus A10 (CV-A10), coxsackievirus A16 (CV-A16) in Ho Chi Minh City, Vietnam from a case data collected during 2013–2018 and a serological survey data collected in 2015 and 2017. We proposed a catalytic model framework with good adaptability to incorporate maternal immunity using various mathematical functions. Our results indicate the high-level transmission of CV-A6 and CV-A10 which is not obvious in the case data, due to the variation of disease severity across serotypes. Our results provide statistical evidence supporting the strong association between severe illness and CV-A6 and EV-A71 infections. The HFMD dynamic pattern presents a cyclical pattern with large outbreaks followed by a decline in subsequent years. Additionally, we identify the age group with highest risk of infection as 1-2 years and emphasise the risk of future outbreaks as over 50% of children aged 6-7 years were estimated to be susceptible to CV-A16 and EV-A71. Our study highlights the importance of multivalent vaccines and active surveillance for different serotypes, supports early vaccination prior to 1 year old, and points out the potential utility for vaccinating children older than 5 years old in Vietnam.

A screening study on the detection strain of Coxsackievirus A6: the key to evaluating neutralizing antibodies in vaccines

ABSTRACT The increasing incidence of diseases caused by Coxsackievirus A6 (CV-A6) and the presence of various mutants in the population present significant public health challenges. Given the concurrent development of multiple vaccines in China, it is challenging to objectively and accurately evaluate the level of neutralizing antibody response to different vaccines. The choice of the detection strain is a crucial factor that influences the detection of neutralizing antibodies. In this study, the National Institutes for Food and Drug Control collected a prototype strain (Gdula), one subgenotype D1, as well as 13 CV-A6 candidate vaccine strains and candidate detection strains (subgenotype D3) from various institutions and manufacturers involved in research and development. We evaluated cross-neutralization activity using plasma from naturally infected adults (n = 30) and serum from rats immunized with the aforementioned CV-A6 strains. Although there were differences between the geometric mean titer (GMT) ranges of human plasma and murine sera, the overall trends were similar. A significant effect of each strain on the neutralizing antibody test (MAX/MIN 48.0 ∼16410.3) was observed. Among all strains, neutralization of the S112 strain by 15 different sera resulted in higher neutralizing antibody titers (GMTS112 = 132.0) and more consistent responses across different genotypic immune sera (MAX/MIN = 48.0). Therefore, S112 may serve as a detection strain for NtAb testing in various vaccines, minimizing bias and making it suitable for evaluating the immunogenicity of the CV-A6 vaccine.

Kaposi varicelliform eruption: an unusual presentation caused by varicella zoster virus in a healthy adult patient - a case report

BackgroundKaposi Varicelliform Eruptions (KVE), also known as eczema herpeticum, is a rare and potentially life-threatening dermatological condition primarily attributed to herpes simplex virus (HSV) infection, with less frequent involvement of Coxsackie A16, vaccinia, Varicella Zoster, and smallpox viruses. Typically associated with pre-existing skin diseases, especially atopic dermatitis, KVE predominantly affects children but can manifest in healthy adults. Characterized by painful clusters of vesicles and sores on the skin and mucous membranes, it often masquerades as other dermatological disorders. Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used for pain relief and inflammation, though their potential role as KVE triggers remains uncertain.Case reportHere, we present a case of an 18-year-old female with KVE attributed to Varicella Zoster virus (VZV) and successfully treated with oral acyclovir within a week, underscoring the significance of early recognition and intervention. KVE can manifest with systemic symptoms like fever, fatigue, and lymphadenopathy and may involve multiple organ systems, necessitating possible antibiotic use for complications.ConclusionThis case underscores the importance of prompt KVE identification and consideration of antiviral therapy to enhance patient outcomes. Further research is warranted to elucidate predisposing factors for this rare condition.

Rapid detection of four major HFMD-associated enteroviruses by multiplex HiFi-LAMP assays.

Hand, foot, and mouth disease (HFMD) caused by various enteroviruses is a major public health concern globally. Human enterovirus 71(EVA71), coxsackievirus A16 (CVA16), coxsackievirus A6 (CVA6), and coxsackievirus A10 (CVA10) are four major enteroviruses responsible for HFMD. Rapid, accurate, and specific point-of-care (POC) detection of the four enteroviruses is crucial for the prevention and control of HFMD. Here, we developed two multiplex high-fidelity DNA polymerase loop-mediated isothermal amplification (mHiFi-LAMP) assays for simultaneous detection of EVA71, CVA16, CVA6, and CVA10. The assays have good specificity and exhibit high sensitivity, with limits of detection (LOD) of 11.2, 49.6, 11.4, and 20.5 copies per 25 μL reaction for EVA71, CVA16, CVA6, and CVA10, respectively. The mHiFi-LAMP assays showed an excellent clinical performance (sensitivity 100.0%, specificity 83.3%, n = 47) when compared with four singleplex RT-qPCR assays (sensitivity 93.1%, specificity 100%). In particular, the HiFi-LAMP assays exhibited better performance (sensitivity 100.0%, specificity 100%) for CVA16 and CVA6 than the RT-qPCR assays (sensitivity 75.0-92.3%, specificity 100%). Furthermore, the mHiFi-LAMP assays detected all clinical samples positive for the four enteroviruses within 30min, obviously shorter than about 1-1.5h by the RT-qPCR assays. The new mHiFi-LAMP assays can be used as a robust point-of-care testing (POCT) tool to facilitate surveillance of HFMD at rural and remote communities and resource-limited settings.

GAMBARAN PENGETAHUAN IBU DALAM PENCEGAHAN PENULARAN FLU SINGAPURA PADA ANAK BALITA

The Singapore’s flu is a viral infection that occurs in children especially toddlers and is often caused by Coxsackievirus A16 (CV-A16) and Enterovirus 71 (EV-71). Most Singaporean flu cases can be cured by themselves with an incubation period of 3-6 days. Delays in providing proper diagnosis and treatment will cause serious complications and can be fatal to the point of death. This can be a warning to the public, especially mothers, to increase their alertness, and to be able to perform good and correct precautions so that children do not contract and do not transmit Singaporean flu disease to others. The purpose of this study is to find a description of mother's knowledge in the prevention of Singaporean flu transmission in toddlers. Methods: Quantitative research used a descriptive method with a sample of 100 mothers who had toddlers taken with purposive sampling techniques with several inclusion criteria. This study used univariate analysis with descriptive statistics. Results: Most respondents were between the ages of 26-35 years (54%), and had children of more than 1 person (66%), senior high school educated respondents (51%), unemployed respondents (84%) and low family economic status (67%), and the majority of mothers had less knowledge in preventing Singaporean flu transmission in children under five (54%). Conclusion: Mother's knowledge in the prevention of transmission of the Singapore flu in children under five is still low, so mothers are expected to be more alert and to find information about the Singapore’s flu.

Adsorption of Coxsackievirus in Sediments: Influencing Factors, Kinetics, and Isotherm Modeling

Drinking groundwater contamination by pathogenic viruses represents a serious risk to worldwide public health, particularly for enteric viruses, which exhibit high prevalence and occurrence during outbreaks. Understanding how enteric viruses adsorb in groundwater is essential to protecting human health and ensuring the sustainable use of water resources. The adsorption properties of Coxsackievirus A16 (CA16), a common gastrointestinal virus that spreads through groundwater, were investigated in this work. A typical batch equilibrium approach was used to investigate CA16 adsorption and factors that influence it. In a laboratory recognized nationally as a biosafety level 2 facility, stringent research protocols were followed to guarantee compliance with experimental standards. The variables that were investigated included the size of the sediment particles, the starting concentration of the virus, temperature, pH level, and humic acid content. The findings showed that the CA16 virus was more strongly attracted to finer sediment particles and that its adsorption increased as the size of the sediment particle decreased. Furthermore, it was discovered that higher temperatures improved the CA16 virus’s ability to bind to sediment particles. The pH of the aqueous environment has a significant effect on the effectiveness of virus adsorption; higher effectiveness was seen in acidic environments. Furthermore, it was found that the presence of humic acid decreased the ability of clay to adsorb CA16, suggesting that humic acid has a detrimental influence on clay’s ability to adsorb viruses. The examination of kinetic models demonstrated that, in every scenario examined, the adsorption process of CA16 adhered to the pseudo-second-order kinetics model. Additionally, the Langmuir and Freundlich isotherm models were used to assess the equilibrium data that were collected in this investigation. The outcomes amply proved that the most accurate representation of the adsorption equilibrium was given by the Langmuir isotherm model. The study offered a solid scientific foundation for treating groundwater and creating plans to stop the spread of viruses.

Enterovirus D68 3C protease antagonizes type I interferon signaling by cleaving signal transducer and activator of transcription 1.

Following the successful control of poliovirus, the re-emergence of respiratory enterovirus D68 (EV-D68), a prominent non-polio enterovirus, has become a serious public health concern worldwide. Host innate immune responses are the primary defense against EV-D68 invasion; however, the mechanism underlying viral evasion of the antiviral activity of interferons (IFN) remains unclear. In this study, we found that EV-D68 inhibited type I IFN signaling by cleaving signal transducer and activator of transcription 1 (STAT1), a crucial factor in cellular responses to interferons and other cytokines. We observed that the prototype and circulating EV-D68 strains conserved their ability to induce STAT1 cleavage and attenuate IFN signal transduction. Further investigation revealed that EV-D68 3C protease cleaves STAT1 at the 131Q residue. Interestingly, not all enterovirus-encoded 3C proteases exhibited this ability. EV-D68 and poliovirus 3C proteases efficiently induced STAT1 cleavage; whereas, 3C proteases from EV-A71, coxsackievirus A16, and echoviruses did not. STAT1 cleavage also abolished the nuclear translocation capacity of STAT1 in response to IFN stimulation to activate downstream signaling elements. Overall, these results suggest that STAT1, targeted by viral protease 3C, is utilized by EV-D68 to subvert the host's innate immune response.IMPORTANCEEnterovirus D68 (EV-D68) has significantly transformed over the past decade, evolving from a rare pathogen to a potential pandemic pathogen. The interferon (IFN) signaling pathway is an important defense mechanism and therapeutic target for the host to resist viral invasion. Previous studies have reported that the EV-D68 virus blocks or weakens immune recognition and IFN production in host cells through diverse strategies; however, the mechanisms of EV-D68 resistance to IFN signaling have not been fully elucidated. Our study revealed that EV-D68 relies on its own encoded protease, 3C, to directly cleave signal transducer and activator of transcription 1 (STAT1), a pivotal transduction component in the IFN signaling pathway, disrupting the IFN-mediated antiviral response. Previous studies on human enteroviruses have not documented direct cleavage of the STAT1 protein to evade cellular immune defenses. However, not all enteroviral 3C proteins can cleave STAT1. These findings highlight the diverse evolutionary strategies different human enteroviruses employ to evade host immunity.

Tribbles Pseudokinase 3 promotes enterovirus A71 infection via dual mechanisms

Enterovirus A71 (EV-A71) is the main pathogen causing hand, foot and mouth disease (HFMD) in children and occasionally associated with neurological diseases such as aseptic meningitis, brainstem encephalitis (BE) and acute flaccid paralysis. We report here that cellular pseudokinase tribbles 3 (TRIB3) facilitates the infection of EV-A71 via dual mechanisms. In one hand, TRIB3 maintains the metabolic stability of scavenger receptor class B member 2 (SCARB2), the bona fide receptor of EV-A71, to enhance the infectious entry and spreading of the virus. On the other hand, TRIB3 facilitates the replication of EV-A71 RNA in a SCARB2-independent manner. The critical role of TRIB3 in EV-A71 infection and pathogenesis was further demonstrated in vivo in mice. In comparison to wild-type C57BL/6 mice, EV-A71 infection in TRIB3 knockdown mice (Trib3 +/-) resulted in significantly lower viral loads in muscular tissues and reduced lethality and severity of clinical scores and tissue pathology. In addition, TRIB3 also promoted the replication of coxsackievirus B3 (CVB3) and coxsackievirus A16 (CVA16) in vitro. In conclusion, our results suggest that TRIB3 is one of key host cellular proteins required for the infection and pathogenesis of EV-A71 and some other human enteroviruses and may thus be a potential therapeutic target for combating the infection of those viruses.

Pathogenicity and landscape of differential gene expression in mice orally infected with clinical coxsackievirus A6 (CA6).

Hand, foot, and mouth disease (HFMD) is caused by more than 20 pathogenic enteroviruses belonging to the Picornaviridae family and Enterovirus genus. Since the introduction of the enterovirus-71 (EV71) vaccine in 2016, the number of HFMD cases caused by EV71 has decreased. However, cases of infections caused by other enteroviruses, such as coxsackievirus A6 (CA6) and coxsackievirus A10, have been increasing accordingly. In this study, we used a clinical isolate of CA6 to establish an intragastric infection mouse model using 7-day-old mice to mimic the natural transmission route, by which we investigated the differential gene expression profiles associated with virus infection and pathogenicity. After intragastric infection, mice exhibited hind limb paralysis symptoms and weight loss, similar to those reported for EV71 infection in mice. The skeletal muscle was identified as the main site of virus replication, with a peak viral load reaching 2.31 × 107 copies/mg at 5 dpi and increased infiltration of inflammatory cells. RNA sequencing analysis identified differentially expressed genes (DEGs) after CA6 infection. DEGs in the blood, muscle, brain, spleen, and thymus were predominantly enriched in immune system responses, including pathways such as Toll-like receptor signaling and PI3K-Akt signaling. Our study has unveiled the genes involved in the host immune response during CA6 infection, thereby enhancing our comprehension of the pathological mechanism of HFMD.IMPORTANCEThis study holds great significance for the field of hand, foot, and mouth disease (HFMD). It not only delves into the disease's etiology, transmission pathways, and severe complications but also establishes a novel mouse model that mimics the natural coxsackievirus A6 infection process, providing a pivotal platform to delve deeper into virus replication and pathogenic mechanisms. Additionally, utilizing RNA-seq technology, it unveils the dynamic gene expression changes during infection, offering valuable leads for identifying novel therapeutic drug targets. This research has the potential to enhance our understanding of HFMD, offering fresh perspectives for disease prevention and treatment and positively impacting children's health worldwide.

Evolutionary Diversity of Coxsackievirus A6 Causing Severe Hand, Foot, and Mouth Disease - China, 2012-2023.

Coxsackievirus A6 (CVA6) has emerged as a significant pathogen responsible for severe cases of hand, foot, and mouth disease (HFMD). This study aims to delineate the demographic characteristics and analyze the viral evolution of severe HFMD associated with CVA6, thereby assisting in its surveillance and management. In this investigation, 74 strains of CVA6 were isolated from samples collected from severe HFMD cases between 2012 and 2023. The VP1 gene sequences of CVA6 were amplified and analyzed to assess population historical dynamics and evolutionary characteristics using BEAST, DnaSP6, and PopART. A significant portion (94.4%) of severe CVA6-associated HFMD cases (51 out of 54, with 20 lacking age information) were children under 5 years old. Among the 74 CVA6 strains analyzed, 72 belonged to the D3a sub-genotype, while only two strains were D2 sub-genotype. The average genetic distance between VP1 sequences prior to 2015 was 0.027, which increased to 0.051 when compared to sequences post-2015. Historical population dynamics analysis indicated three significant population expansions of severe CVA6-associated HFMD during 2012-2013, 2013-2014, and 2019-2020, resulting in the formation of 65 distinct haplotypes. Consistent with the MCC tree findings, transitioning between regional haplotypes required multiple base substitutions, showcasing an increase in population diversity during the evolutionary process (from 14 haplotypes in 2013 to 55 haplotypes over the subsequent decade). CVA6, associated with severe HFMD, is evolving and presents a risk of outbreak occurrence. Thus, enhanced surveillance of severe HFMD is imperative.

Study on the epidemiological characteristics of enterovirus among pediatric patients in Hangzhou, China: A comparison between the pre-COVID-19, COVID-19 pandemic, and post-COVID-19 periods.

Nonpharmaceutical interventions (NPIs) for coronavirus disease 2019 (COVID-19) not only reduce the prevalence of this disease among children but also influence the transmission of other viruses. This retrospective study investigated the impact of NPIs on human enterovirus (HEV) infection in children diagnosed with hand, foot, and mouth disease (HFMD) or herpangina (HA) in Hangzhou, China. We collected and analyzed the laboratory results and clinical data of children diagnosed with HFMD or HA during the following periods: pre-COVID-19 (January 2019 to December 2019), the COVID-19 pandemic (January 2020 to December 2022), and post-COVID-19 (January to December 2023). A total of 41 742 specimens that met the inclusion criteria were obtained, of which 1998 (4.79%) tested positive for enterovirus. In comparison to those in the pre-COVID-19 period, which had 695 (5.63%) HEV-positive specimens, the numbers dramatically decreased to 69 (1.19%), 398 (5.12%), and 112 (1.58%) in 2020, 2021, and 2022, respectively, but significantly increased to 724 (8.27%) in 2023. Seasonal peaks of infections occurred in May, June, July, and August each year, with the total detection rate ranging from 2019 to 2023 being 9.41% in May, 22.47% in June, 28.23% in July, and 12.16% in August, respectively. The difference in the detection rates of HEV infection between males and females was statistically significant (p < 0.005), with 5.11% (1221/23 898) of males and 4.35% (777/17 844) of females testing positive, resulting in a male-to-female positive ratio of 1.57:1. Among the age groups, 11.25% (378/3360) of the children aged 3-5 years had the highest detection rate, which steadily decreased with increasing or decreasing age. The detection of HEV indicated that >95% of the viruses were other types than the previously commonly reported enterovirus 71 (EV-A71) and coxsackievirus A16 (CV-A16). In conclusion, NPIs for COVID-19 may be effective at reducing the transmission of HEV. However, with the relaxation of NPIs, the detection rate of HEVs increased slowly to a certain extent. Active awareness and surveillance of the epidemiological characteristics of HEV are essential for preventing, controlling, and managing the development of HFMD and HA, as well as contributing to the development of a multivalent HFMD vaccine.

ПРОЯВЛЕНИЯ ЭПИДЕМИЧЕСКОГО ПРОЦЕССА ЭНТЕРОВИРУСНОЙ ИНФЕКЦИИ В СУБЪЕКТАХ ДАЛЬНЕВОСТОЧНОГО И СИБИРСКОГО ФЕДЕРАЛЬНЫХ ОКРУГОВ РОССИЙСКОЙ ФЕДЕРАЦИИ В 2023 Г. ПРОГНОЗ ЗАБОЛЕВАЕМОСТИ ЭНТЕРОВИРУСНОЙ ИНФЕКЦИЕЙ НА 2024 Г.

The annual increase in the incidence of enterovirus infection (EVI) in the population of the Far East and Eastern Siberia determines the need for constant epidemiological surveillance of EVI using molecular typing of enteroviruses.In 2023, a significant excess of the long-term average incidence rate of EVI was noted in 8 of the 16 analyzed territories of the Far Eastern and Siberian federal districts. The main clinical forms of EVI were herpangina and exanthema forms. Among the identified types of enteroviruses in 2023, coxsackievirus A6 predominated. Phylogenetic analysis revealed the circulation of a new variant of the eC2 genotype of the ECHO30. The calculation of prognostic indicators showed that an increase in EVI incidence in 2024 is expected in five analyzed territories. The manifestations of the EVI epidemic process in the territories of the Far Eastern and Siberian federal districts in 2023 were influenced by the active circulation of the coxsackievirus A6 and the emergence of a new ECHO30 genovariant. In the territories with high EVI incidence rates predicted for 2024, attention should be paid to the timely organization of epidemic control measures.

Течение энтеровирусной инфекции у детей в Краснодарском крае на современном этапе

Objective. To determine the clinical and epidemiologic features of the course of enterovirus infection (EVI) in Krasnodar Krai. Patients and methods. We analyzed the case histories of children who were treated in the State Budgetary Institution "SKDIB" of Krasnodar from January 2020 to November 2023. For the period from 01.01.2020 to 30.06.2022, out of 1560 patients with suspected acute infectious pathology, EVI was detected in 98 children, of whom boys accounted for 59.2% (n = 58), girls – 40.8% (n = 40). After removal of restrictions on new coronavirus infection from 01.07.2022 to November 2023, EVI was detected in 366 out of 2607 examined patients, of which boys accounted for 55.3% (n = 202), girls – 44.7% (n = 164). Most children (231, 63.1%) came from organized groups. In all forms of EVI, nasopharyngeal swabs, feces, and vesicle contents were examined by polymerase chain reaction; enterovirus RNA was detected in all patients. Molecular typing of enteroviruses was performed in the Federal Budgetary Institution "Center of Hygiene and Epidemiology in Krasnodar Krai". Results. It was revealed that exanthem and neurological forms prevailed during the given periods of observation.Of neurological lesions of EVI, enteroviral meningitis remains the leading form, which as an independent form occurred in 66.9% of cases, in combination with herpangina, exanthema, diarrhea – in 33.1%. The incidence rate of enteroviral meningitis for the period from 07.2022 to 11.2023 is 36.6%, the proportion of encephalitis increased to 2.7%. In the age structure of EVI cases for the period from 01.2020 to 06.2022, the main share was children aged 1 to 3 years old (42, 41.1%), for the period 07.2022–11.2023 – children from 4 to 6 years old (219, 59.9%). Conclusion. All age groups of children were involved in the epidemic process, but children aged 1 to 3 years (45.9%) and 7 to 14 years (22.4%) were sick more often, with the highest number of cases registered in preschool and school educational organizations. The greatest risk of developing severe forms of EVI is observed in children from risk groups. In recent years, there are still risks of epidemic rise in the incidence of exanthem and minor forms of EVI associated with the spread of Coxsackie A6, A16 and other viruses of the Coxsackie A and B species, the probability of spread of enterovirus A71 and possible resumption of circulation of EUNO 30 virus cannot be excluded. Key words: children, enterovirus infection, enteroviral exanthema, enteroviral meningitis, clinic

Analysis of miRNAs involved in mouse brain injury upon Coxsackievirus A6 infection.

Coxsackievirus A6 (CV-A6) has emerged as the predominant epidemic strain responsible for hand, foot and mouth disease (HFMD). CV-A6 infection can result in severe clinical manifestations, including encephalitis, meningitis, and potentially life-threatening central nervous system disorders. Our previous research findings demonstrated that neonatal mice infected with CV-A6 exhibited limb weakness, paralysis, and ultimately succumbed to death. However, the underlying mechanism of CV-A6-induced nervous system injury remains elusive. Numerous reports have highlighted the pivotal role of miRNAs in various viral infections. Separately established infection and control groups of mice were used to create miRNA profiles of the brain tissues before and after CV-A6 transfection, followed by experimental verification, prediction, and analysis of the results. At 2 days post-infection (dpi), 4 dpi, and 2dpi vs 4dpi, we identified 175, 198 and 78 significantly differentially expressed miRNAs respectively using qRT-PCR for validation purposes. Subsequently, we predicted target genes of these differentially expressed miRNAs and determined their potential targets through GO (Gene Ontology) enrichment analysis and KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analysis. Finally, we verified the miRNA-mRNA pairing via double luciferase experiments while confirming functional enrichment of target genes through Western Blotting analyses. The results from this study suggest that transcriptional regulation, neuronal necrosis, pro-inflammatory cytokine release, and antiviral immunity are all implicated in the pathogenesis of central nervous system injury in mice infected with CV-A6. Brain injury resulting from CV-A6 infection may involve multiple pathways, including glial cell activation, neuronal necrosis, synaptic destruction, degenerative diseases of the nervous system. It can even encompass destruction of the blood-brain barrier, leading to central nervous system injury. The dysregulated miRNAs and signaling pathways discovered in this study provide valuable insights for further investigations into the pathogenesis of CV-A6.

Current Status of Research on Coxsackievirus A6 Hand, Foot and Mouth Disease

Current Status of Research on Coxsackievirus A6 Hand, Foot and Mouth Disease

Development and evaluation of a CRISPR-Cas13a system-based diagnostic for hepatitis E virus.

Hepatitis E virus (HEV) is the leading cause of acute viral hepatitis worldwide. HEV RNA detection is the goldstandard for HEV infection diagnosis and PCR methods are commonly used but are usually time-consuming and expensive, resulting in low detection efficiency and coverage, especially in low-income areas. Here, we developed a simpler and more accessible HEV RNA detection method based on CRISPR-Cas13a system. A total of 265 samples of different types and sources, including 89 positive samples and 176 negative samples, were enrolled for evaluations. The sensitivity andspecificity of the Cas13a-crRNA detection system were evaluated. The World Health Organization reference panel for HEV genotypes was used to evaluate the capability for detecting different HEV genotypes. The validity of the assay was compared with RT-qPCR. The 95 % limits of detection (LOD) of Cas13a-crRNA-based fluorescence assay and strip assay were 12.5 and 200 IU/mL, respectively. They did not show cross-reactivity with samples positive for hepatitis A virus, hepatitis B virus, hepatitis C virus, coxsackievirus A16, rotavirus, enterovirus 71, norovirus or enteropathic Escherichia coli. Different HEV genotypes (HEV1-4) can be detected by the assay. Compared to RT-qPCR, the positive predictive agreements of Cas13a-crRNA-based fluorescence and strip assay were 98.9 % (95 % CI: 93.9-99.8 %) and 91.0 % (95 % CI: 83.3-95.4 %), respectively. The negative predictive agreements were both 100 % (95 % CI: 97.8-100 %). In conclusion, we established a rapid and convenient HEV RNA detection method with good sensitivity and specificity based on CRISPR-Cas13a system, providing anew option for HEV infection diagnosis.

Antiviral Mechanisms of Saucerneol from Saururus chinensis against Enterovirus A71, Coxsackievirus A16, and Coxsackievirus B3: Role of Mitochondrial ROS and the STING/TKB-1/IRF3 Pathway.

Enterovirus A71 (EV71), coxsackievirus A16 (CVA16), and coxsackievirus B3 (CVB3) are pathogenic members of the Picornaviridae family that cause a range of diseases, including severe central nervous system complications, myocarditis, and pancreatitis. Despite the considerable public health impact of these viruses, no approved antiviral treatments are currently available. In the present study, we confirmed the potential of saucerneol, a compound derived from Saururus chinensis, as an antiviral agent against EV71, CVA16, and CVB3. In the in vivo model, saucerneol effectively suppressed CVB3 replication in the pancreas and alleviated virus-induced pancreatitis. The antiviral activity of saucerneol is associated with increased mitochondrial ROS (mROS) production. In vitro inhibition of mROS generation diminishes the antiviral efficacy of saucerneol. Moreover, saucerneol treatment enhanced the phosphorylation of STING, TBK-1, and IRF3 in EV71- and CVA16-infected cells, indicating that its antiviral effects were mediated through the STING/TBK-1/IRF3 antiviral pathway, which was activated by increased mROS production. Saucerneol is a promising natural antiviral agent against EV71, CVA16, and CVB3 and has potential against virus-induced pancreatitis and myocarditis. Further studies are required to assess its safety and efficacy, which is essential for the development of effective antiviral strategies against these viruses.