Mechanism and potential treatments for gastrointestinal dysfunction in patients with COVID-19.

The global coronavirus disease 2019 (COVID-19) has become one of the biggest threats to the world since 2019. The respiratory and gastrointestinal tracts are the main targets for severe acute respiratory syndrome coronavirus 2 infection for they highly express angiotensin-converting enzyme-2 and transmembrane protease serine 2. In patients suffering from COVID-19, gastrointestinal symptoms have ranged from 12% to 61%. Anorexia, nausea and/or vomiting, diarrhea, and abdominal pain are considered to be the main gastrointestinal symptoms of COVID-19. It has been reported that the direct damage of intestinal mucosal epithelial cells, malnutrition, and intestinal flora disorders are involved in COVID-19. However, the underlying mechanisms remain unclear. Thus, in this study, we reviewed and discussed the correlated mechanisms that cause gastrointestinal symptoms in order to help to develop the treatment strategy and build an appropriate guideline for medical workers.

Molecular characterization of the FCoV-like canine coronavirus HLJ-071 in China.

BACKGROUND: According to the differences of antigen and genetic composition, canine coronavirus (CCoV) consists of two genotypes, CCoV-I and CCoV-II. Since 2004, CCoVs with point mutations or deletions of NSPs are contributing to the changes in tropism and virulence in dogs. RESULTS: In this study, we isolated a CCoV, designated HLJ-071, from a dead 5-week-old female Welsh Corgi with severe diarrhea and vomit. Sequence analysis suggested that HLJ-071 bearing a complete ORF3abc compared with classic CCoV isolates (1-71, K378 and S378). In addition, a variable region was located between S gene and ORF 3a gene, in which a deletion with 104 nts for HLJ-071 when compared with classic CCoV strains 1-71, S378 and K378. Phylogenetic analysis based on the S gene and complete sequences showed that HLJ-071 was closely related to FCoV II. Recombination analysis suggested that HLJ-071 originated from the recombination of FCoV 79-1683, FCoV DF2 and CCoV A76. Finally, according to cell tropism experiments, it suggested that HLJ-071 could replicate in canine macrophages/monocytes cells. CONCLUSION: The present study involved the isolation and genetic characterization of a variant CCoV strain and spike protein and ORF3abc of CCoV might play a key role in viral tropism, which could affect the replication in monocyte/macrophage cells. It will provide essential information for further understanding the evolution in China.

The roles of nausea and vomiting in COVID-19: did we miss something?

The Coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is an international public health emergency. Although respiratory symptoms predominate the clinical manifestations of COVID-19, gastrointestinal symptoms have been observed in a subset of patients. Notably, some patients have nausea/vomiting as the first clinical manifestation of COVID-19, which is often overlooked by people. It is now clear that not only the lungs, the gastrointestinal tract could also be attacked by SARS-CoV-2. Its host receptor angiotensin-converting enzyme 2 (ACE2), which acts as a gateway to infection, has been found to be highly expressed in the gastrointestinal epithelium and may lead to the development of nausea/vomiting. Raise awareness of these symptoms and take timely intervention would help people combat the pandemic. This review discussed epidemiology, mechanisms, management, and prevention of COVID-19 related nausea and vomiting.

Clinical Characteristics of 195 Cases of COVID-19 with Gastrointestinal Symptoms COVID-19 with Gastrointestinal Symptoms.

BACKGROUND: Patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), have fever, dry cough, dyspnea, and fatigue. The disease has now become a global pandemic. The purpose of this study was to explore the relationship between COVID-19 and gastrointestinal (GI) symptoms. METHODS: We collected and analyzed data on patients with laboratory-confirmed COVID-19 by high-throughput sequencing or reverse transcription-polymerase chain reaction. We reviewed electronic medical records of 405 hospitalized COVID-19 patients in the Third Hospital of Wuhan. RESULTS: Among the 405 confirmed patients, 210 had no GI symptoms, 195 had GI symptoms, and the first symptom of 155 patients was GI. The prevalence of vascular and digestive diseases in the group with GI symptoms was significantly higher than in the group without GI symptoms. In patients with GI symptoms, the proportion with fever, cough, dysphoria, chest tightness, poor appetite, chest pain, and pharyngeal pain was significantly higher than in those without GI symptoms. There was no significant difference in imaging between the 2 groups. In patients with GI symptoms, the proportion with increased procalcitonin (PCT) level and decreased lymphocyte count was significantly higher than in those without GI symptoms. CONCLUSION: COVID-19 patients with GI symptoms had significantly more vascular and digestive system diseases and were more likely to have clinical manifestations of fever, cough, poor appetite, chest tightness, chest pain, insomnia, and pharyngeal pain. There were more patients with diarrhea, nausea, and vomiting. Patients with GI symptoms were more likely to have increased PCT and decreased lymphocyte count.

The characteristics of gastrointestinal symptoms in patients with severe COVID-19: a systematic review and meta-analysis.

Although primarily a respiratory illness, several studies have shown that COVID-19 causes elevation of liver enzymes and various gastrointestinal (GI) symptoms. The aim of this study was to undertake a systematic review and meta-analysis to determine whether the presence of gastrointestinal (GI) symptoms contributed toward COVID-19 severity, and identify the GI symptoms characteristic of severe COVID-19. We conducted a literature search of PubMed from December 1, 2019, to June 30, 2020, and identified all reports with GI symptoms reported. A meta-analysis comparing the severity of COVID-19 with the presence of liver enzyme elevation and GI symptoms was performed using RevMan version 5.4. Pooled data from 15,305 unique reverse transcriptase-polymerase chain reaction positive COVID-19 patients from 44 studies were analyzed. We found that the severe COVID-19 patients significantly had abdominal pain compared to the non-severe COVID-19 patients (OR = 2.70, 95% CI 1.17-6.27, Z = 2.32, p = 0.02, I2 = 0%) by analyzed 609 patients of 4 studies who reported both abdominal pain and COVID-19 severity. However, there was no significant difference in the incidence of diarrhea, nausea, or vomiting between the two groups. Thus, this systematic review and meta-analysis demonstrated that abdominal pain could be characteristic of severe COVID-19 infections. Compared with other viral infections that primarily infect the respiratory system, patients with COVID-19 have a slightly lower frequency of diarrheal symptoms with abdominal pain. However, to confirm this, further studies with COVID-19 patients across various countries and ethnicities are required.

Symptômes associés au frottis SRAS-CoV-2-positif chez des enfants de l'Alberta.

CONTEXTE: La recherche sur les enfants atteints d'une infection à coronavirus du syndrome respiratoire aigu sévère 2 (SRAS-CoV-2) a principalement porté sur les enfants amenés aux services des urgences. Nous avons voulu identifier les symptômes plus souvent associés à un frottis SRAS-CoV-2-positif chez les enfants non hospitalisés. MÉTHODES: Nous avons procédé à une étude observationnelle chez des enfants soumis au dépistage et suivis pour une infection à SRAS-CoV-2 confirmée sur des prélèvements de sécrétions nasales, nasopharyngées, de la gorge et autres (p. ex., aspiration nasopharyngée, sécrétions trachéales ou non spécifiées) entre le 13 avril et le 30 septembre 2020 en Alberta. Nous avons calculé les rapports de vraisemblance (RV) positifs entre les symptômes autodéclarés et les frottis SRAS-CoV-2-positifs dans la cohorte entière et dans 3 analyses de sensibilité : tous les enfants présentant au moins 1 symptôme, tous les enfants, symptomatiques ou non, soumis au dépistage par suite d'une recherche de contacts, et tous les enfants de 5 ans et plus. RÉSULTATS: Nous avons analysé les résultats chez 2463 enfants soumis au dépistage de l'infection à SRAS-CoV-2; 1987 enfants se sont révélés positifs et 476 négatifs. Parmi les enfants SRAS-CoV-2-positifs, 714 (35,9 %) n'ont déclaré aucun symptôme. Même si la toux (24,5 %) et la rhinorrhée (19,3 %) étaient les 2 symptômes les plus fréquents chez les enfants ayant contracté le SRAS-CoV-2, elles étaient fréquentes également chez ceux dont les résultats étaient négatifs et ne permettaient pas de prédire un résultat positif (RV positif 0,96, intervalle de confiance [IC] à 95 % 0,81­1,14 et 0,87, IC à 95 % 0,72­1,06, respectivement). L'anosmie/agueusie (RV positif 7,33, IC à 95 % 3,03­17,76), les nausées et vomissements (RV positif 5,51, IC à 95 % 1,74­17,43), les céphalées (RV positif 2,49, IC à 95 % 1,74­3,57) et la fièvre (RV positif 1,68, IC à 95 % 1,34­2,11) ont été les symptômes les plus prédictifs d'un résultat SRAS-CoV-2-positif. Le RV positif pour la combinaison anosmie et agueusie, nausées et vomissements, et céphalées était de 65,92 (IC à 95 % 49,48­91,92). INTERPRÉTATION: Environ les deux tiers des enfants déclarés SRAS-CoV-2-positifs ont manifesté des symptômes, et les symptômes les plus étroitement associés à un frottis SRAS-CoV-2-positif étaient l'anosmie/agueusie, les nausées et les vomissements, les céphalées et la fièvre.

An acute gastroenteritis outbreak associated with breakfast contaminated with norovirus by asymptotic food handler at a kindergarten in Shenzhen, China.

BACKGROUND: An outbreak of acute gastroenteritis occurred in a kindergarten located Shenzhen City on March 4, 2018. We were invited to investigate to the risk factors associated with this outbreak. METHODS: We conducted retrospective cohort-studies on three different groups of subjects in order to figure out the difference of incidence of acute gastroenteritis among subjects of different activities on March 2: group one consisted of people who attended the Lantern festival activities; group two consisted of children and employees who ate breakfast and bread provided by the kindergarten; and groups three consisted of children and employees who did not eat breakfast or bread provided by the kindergarten. Fecal, anal swabs, dishware swabs and hand swabs specimens were collected in the study. Bacteria known to cause acute gastroenteritis were cultured. Viruses associated with acute gastroenteritis were tested using real-time PCR. Capsid gene fragment of 557 bp of norovirus was amplified and sequenced. The phylogenetic tree was constructed with MEGA 7.0 using neighbor-joining method based on capsid gene fragment of norovirus. RESULTS: A total of 143 suspected cases were identified in this outbreak. Diarrhea happened more often in adults than in children while emesis and bellyache were more frequently found in children than in adults. Higher AGE incidence was observed in group 2, children and employees who had breakfast in the kindergarten on March 2, as well as in group 3, and among employees who eating bread involved in breakfast provided on March 2. Five anal swab specimens were positive for norovirus. All noroviruses belongs to group II.3 and have an identity more than 99%. CONCLUSION: A chef, as an asymptomatic carrier with norovirus, was the infectious resource in this outbreak. He contaminated breakfast food provided on March 2. Although morning check is implemented in kindergartens of China, employees are often excluded in morning check. Our finding highlights the importance of morning check covering employees and periodical training for cooks.

Features of Intestinal Disease Associated With COVID-Related Multisystem Inflammatory Syndrome in Children.

ABSTRACT: Multisystem inflammatory syndrome in children (MIS-C) is a recently identified syndrome that appears to be temporally associated with novel coronavirus 2019 infection. MIS-C presents with fever and evidence of systemic inflammation, which can manifest as cardiovascular, pulmonary, neurologic, and gastrointestinal (GI) system dysfunction. Presenting GI symptoms are seen in the majority, including abdominal pain, diarrhea, and vomiting. Any segment of the GI tract may be affected; however, inflammation in the ileum and colon predominates. Progressive bowel wall thickening can lead to luminal narrowing and obstruction. Most will have resolution of intestinal inflammation with medical therapies; however, in rare instances, surgical resection may be required.

Clinical Characteristics of COVID-19 Patients With Gastrointestinal Symptoms in Northern Italy: A Single-Center Cohort Study.

INTRODUCTION: The most typical presentation of COVID-19 is an acute respiratory syndrome whose most common symptoms include fever, cough, and dyspnea. However, gastrointestinal symptoms, such as diarrhea and nausea/vomiting, are increasingly reported in patients affected by COVID-19. This study aimed to describe the prevalence and time of onset of gastrointestinal symptoms in patients affected by COVID-19 and to find potential associations between gastrointestinal symptoms and clinical outcomes. METHODS: We performed a prospective single-center cohort study, enrolling patients who received diagnosis of COVID-19 at our institution between March 23, 2020, and April 5, 2020. We collected patient demographics and medical history, laboratory data, and clinical outcomes. Furthermore, we used a specifically designed questionnaire, administered to patients at time of diagnosis, to obtain data on the presence and time of onset of fever, typical respiratory symptoms, gastrointestinal symptoms, and other symptoms (fatigue, headache, myalgia/arthralgia, anosmia, ageusia/dysgeusia, sore throat, and ocular symptoms). RESULTS: In our cohort, 138 (69%) of 190 patients showed at least 1 gastrointestinal symptom at diagnosis; if excluding hyporexia/anorexia, 93 patients (48.9%) showed at least 1 gastrointestinal symptom. Gastrointestinal symptoms, in particular diarrhea, were associated with a lower mortality. At multivariate analysis, diarrhea was confirmed as independent predictive factor of lower mortality. DISCUSSION: Gastrointestinal symptoms are very frequent in patients with COVID-19 and may be associated with a better prognosis. These data suggest that, in some patients, the gastrointestinal tract may be more involved than the respiratory system in severe acute respiratory syndrome coronavirus 2 infection, and this could account for the less severe course of disease.

COVID-19, nausea, and vomiting.

Exclusion of nausea (N) and vomiting (V) from detailed consideration as symptoms of COVID-19 is surprising as N can be an early presenting symptom. We examined the incidence of NV during infection before defining potential mechanisms. We estimate that the overall incidence of nausea (median 10.5%), although variable, is comparable with diarrhea. Poor definition of N, confusion with appetite loss, and reporting of N and/or V as a single entity may contribute to reporting variability and likely underestimation. We propose that emetic mechanisms are activated by mediators released from the intestinal epithelium by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) modulate vagal afferents projecting to the brainstem and after entry into the blood, activate the area postrema (AP) also implicated in anorexia. The receptor for spike protein of SARS-CoV-2, angiotensin 2 converting enzyme (ACE2), and transmembrane protease serine (for viral entry) is expressed in upper gastrointestinal (GI) enterocytes, ACE2 is expressed on enteroendocrine cells (EECs), and SARS-CoV-2 infects enterocytes but not EECs (studies needed with native EECs). The resultant virus-induced release of epithelial mediators due to exocytosis, inflammation, and apoptosis provides the peripheral and central emetic drives. Additionally, data from SARS-CoV-2 show an increase in plasma angiotensin II (consequent on SARS-CoV-2/ACE2 interaction), a centrally (AP) acting emetic, providing a further potential mechanism in COVID-19. Viral invasion of the dorsal brainstem is also a possibility but more likely in delayed onset symptoms. Overall, greater attention must be given to nausea as an early symptom of COVID-19 and for the insights provided into the GI effects of SARS-CoV-2.

An outbreak of gastroenteritis associated with a novel GII.8 sapovirus variant-transmitted by vomit in Shenzhen, China, 2019.

BACKGROUND: Human Sapoviruses (SaVs) has been reported as one of the causative agents of acute gastroenteritis (AGE) worldwide. An outbreak of SaVs affected 482 primary school students during spring activities from February 24 to March 11, 2019 in Shenzhen City, China. Our study was aimed at determining the epidemiology of the outbreak, investigating its origins, and making a clear identification of the SaVs genetic diversity. METHODS: Epidemiological investigation was conducted for this AGE outbreak. Stool samples were collected for laboratory tests of causative agents. Real-time reverse-transcription polymerase chain reaction (rRT-PCR) and conventional RT-PCR were used for detecting and genotyping of SaVs. The nearly complete genome of GII.8 SaV strains were amplified and sequenced by using several primer sets designed in this study. Phylogenetic analysis was performed to characterize the genome of GII.8 SaV strains. RESULTS: The single factor analysis showed that the students who were less than 1.5 m away from the vomitus in classroom or playgroundwere susceptible (P < 0.05). Seven of 11 fecal samples from patients were positive for GII.8 SaV genotype. In this study, we obtained the genome sequence of a SaV GII.8 strain Hu/SaV/2019008Shenzhen/2019 /CHN (SZ08) and comprehensively analyzed the genetic diversity. The phylogenetic analysis showed that the GII.8 strain SZ08 formed an independent branch and became a novel variant of GII.8 genotype. Strain SZ08 harbored 11 specific amino acid variations compared with cluster A-D in full-length VP1. CONCLUSIONS: This study identified SaVs as the causative agents for the AGE outbreak. Strain Hu SZ08 was clustered as independent branch and there was no recombination occurred in this strain SZ08. Further, it might become the predominant strain in diarrhea cases in the near future. Constant surveillance is required to monitor the emerging variants which will improve our knowledge of the evolution of SaVs among humans.

COVID-19 gastrointestinal manifestations: a systematic review.

INTRODUCTION: The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has greatly challenged public health worldwide. A growing number of studies have reported gastrointestinal (GI) symptoms. We performed a systematic review of GI symptoms associated with coronavirus disease 2019 (COVID-19) as well as of the serum levels of biomarkers related to liver function and lesion in SARS-CoV-2-infected individuals. METHODS: We surveyed relevant articles published in English, Spanish, and Portuguese up to July, 2020 in the PubMed, MEDLINE, SciELO, LILACS, and BVS databases. Moreover, we surveyed potentially important articles in journals such as the NEJM, JAMA, BMJ, Gut, and AJG. RESULTS: This systematic review included 43 studies, including 18,246 patients. Diarrhea was the most common GI symptom, affecting 11.5% of the patients, followed by nausea and vomiting (6.3%) and abdominal pain (2.3%). With regard to clinical severity, 17.5% of the patients were classified as severely ill, whereas 9.8% of them were considered to have a non-severe disease. Some studies showed increased aspartate transaminase and alanine aminotransferase levels in a portion of the 209 analyzed patients and two studies. CONCLUSIONS: Our results suggest that digestive symptoms are common in COVID-19 patients. In addition, alterations in cytolysis biomarkers could also be observed in a lesser proportion, calling attention to the possibility of hepatic involvement in SARS-CoV-2-infected individuals.

Neurological Complications Of Hand, Foot And Mouth Disease In Children: A Review.

BACKGROUND: Hand-Foot-and-Mouth disease (HFMD) is a viral illness commonly seen in young children, characterized by fever, vomiting, ulcerative lesions in oral mucosa, and vesicles on hands and feet. The early symptoms resolve but sometimes, it leads to more harsh neurological complications and even death. Therefore, the objective of this review was set to provide an overview of the symptoms, pathogenic agents, and treatment of neurological complications associated with HFMD. METHODS: We reviewed literature from PubMed and Science Direct covering at least one of our objectives from inception to 4th March 2018. RESULTS: This review represents 6 countries including China, Vietnam, Cambodia, South Korea, Taiwan, and Australia. Fifteen studies with a total of 1043 patients were included. The majority of HFMD cases with neurological complications were reported in China, predominance in boys as compared to girls, with 97% cases under 15 years of age. Meningoencephalitis and brainstem encephalitis contributed 70% of all neurological complications related to HFMD. Human Enterovirus71 genotype C, especially C4a was a causative agent associated with severe complications. Among symptoms, fever, vomiting, myoclonic jerks or seizure, headache, convulsion, and rashes were reported in almost all neurological complications. The common and supportive treatments were the administration of intravenous immunoglobulin and glucocorticoid therapies. CONCLUSIONS: Early detection and appropriate treatment of severe neurological complications can minimize the risk of adverse health outcomes. Evidence based clinical practice guidelines for early detection and treatment would be significant in the management of these devastating neurological complications.

COVID-19 - gastrointestinal and gut microbiota-related aspects.

OBJECTIVE: The aim of this review paper was to discuss the gut microbiota-related aspects of COVID-19 patients. We presented the faecal-oral transmission of SARS-CoV-2, gut microbiota imbalance, and fecal microbiota transplantation as a hidden source of this virus. MATERIALS AND METHODS: We analyzed the available literature (PubMed, Embase, Google Scholar databases) regarding COVID-19 and gut microbiota related aspects. RESULTS: The gastrointestinal symptoms, such as nausea, vomiting, diarrhea, abdominal discomfort/pain, may occur in these patients. Notably, these symptoms may contribute to the severity of COVID-19. Recent several studies have revealed a new SARS-CoV-2 transmission possibility, opening a fresh view on COVID-19. It is observed the possibility of SARS-CoV-2 transmission via faecal-oral route. Fecal microbiota transplantation may be a hidden source of SARS-CoV-2. Additionally, the pharmacological treatment of COVID-19 and other factors may significantly alter the composition of gut microbiota. Among others, loss of bacterial diversity, the decrease of commensal microbes as well as the increase of opportunistic pathogens are observed. CONCLUSIONS: The alterations of gut microbiota in COVID-19 patients consequently may lead to the development of gut dysbiosis-related diseases even after recovery from COVID-19. Therefore, it is recommended to screen stool samples taken from recovered patients at least 35 days after clearance of virus from respiratory tract. Before 35 days period, SARS-CoV-2 may still be detected in feces. It is also recommended to screen the composition as well as the activity of gut microbiota to assess its balance. In the case of gut dysbiosis, there should be introduced an appropriate method of its modulation. Additionally, all the fecal samples which are prepared for fecal microbiota transplantation should be tested for SARS-CoV-2 to provide protection for its recipients.

Meta-analysis of predictive symptoms for Ebola virus disease.

INTRODUCTION: One of the leading challenges in the 2013-2016 West African Ebola virus disease (EVD) outbreak was how best to quickly identify patients with EVD, separating them from those without the disease, in order to maximise limited isolation bed capacity and keep health systems functioning. METHODOLOGY: We performed a systematic literature review to identify all published data on EVD clinical symptoms in adult patients. Data was dual extracted, and random effects meta-analysis performed for each symptom to identify symptoms with the greatest risk for EVD infection. RESULTS: Symptoms usually presenting late in illness that were more than twice as likely to predict a diagnosis of Ebola, were confusion (pOR 3.04, 95% CI 2.18-4.23), conjunctivitis (2.90, 1.92-4.38), dysphagia (1.95, 1.13-3.35) and jaundice (1.86, 1.20-2.88). Early non-specific symptoms of diarrhoea (2.99, 2.00-4.48), fatigue (2.77, 1.59-4.81), vomiting (2.69, 1.76-4.10), fever (1.97, 1.10-4.52), muscle pain (1.65, 1.04-2.61), and cough (1.63, 1.24-2.14), were also strongly associated with EVD diagnosis. CONCLUSIONS: The existing literature fails to provide a unified position on the symptoms most predictive of EVD, but highlights some early and late stage symptoms that in combination will be useful for future risk stratification. Confirmation of these findings across datasets (or ideally an aggregation of all individual patient data) will aid effective future clinical assessment, risk stratification tools and emergency epidemic response planning.

Where are we with understanding of COVID-19?

Coronavirus disease 2019 caused by SARS-CoV-2 originated from China and spread across every corner of the world. The scientific interest on COVID-19 increased after WHO declared it a pandemic in the early February of 2020. In fact, this pandemic has had a worldwide impact on economy, health, and lifestyle like no other in the last 100 years. SARS-CoV-2 belongs to Coronaviridae family and causes the deadliest clinical manifestations when compared to other viruses in the family. COVID-19 is an emerging zoonotic disease that has resulted in over 383,000 deaths around the world. Scientists are scrambling for ideas to develop treatment and prevention strategies to thwart the disease condition. In this review, we have attempted to summarize the latest information on the virus, disease, prevention, and treatment strategies. The future looks promising.

Molecular epidemiology of enteroviruses associated with severe hand, foot and mouth disease in Shenzhen, China, 2014-2018.

In this study, we investigated the epidemiology and molecular characteristics of enteroviruses associated with severe hand, foot and mouth disease (HFMD) in Shenzhen, China, during 2014-2018. A total of 137 fecal specimens from patients with severe HFMD were collected. Enterovirus (EV) types were determined using real-time reverse transcription polymerase chain reaction (RT-PCR), RT nested PCR, and sequencing. Sequences were analyzed using bioinformatics programs. Of 137 specimens tested, 97 (70.8%), 12 (8.8%), and 10 (7.3%) were positive for EV-A71, coxsackievirus A6 (CVA6), and CVA16, respectively. Other pathogens detected included CVA2 (2.9%, 4/137), CVA10 (2.9%, 4/137), CVA5 (0.7%, 1/137), echovirus 6 (E6) (0.7%, 1/137) and E18 (0.7%, 1/137). The most frequent complication in patients with proven EV infections was myoclonic jerk, followed by aseptic encephalitis, tachypnea, and vomiting. The frequencies of vomiting and abnormal eye movements were higher in EV-A71-infected patients than that in CVA6-infected or CVA16-infected patients. Molecular phylogeny based on the complete VP1 gene revealed no association between the subgenotype of the virus and disease severity. Nevertheless, 12 significant mutations that were likely to be associated with virulence or the clinical phenotype were observed in the 5'UTR, 2Apro, 2C, 3A, 3Dpol and 3'UTR of CVA6. Eight significant mutations were observed in the 5'UTR, 2B, 3A, 3Dpol and 3'UTR of CVA16, and 10 significant mutations were observed in the 5'UTR, VP1, 3A and 3Cpro of CVA10. In conclusion, EV-A71 is still the main pathogen causing severe HFMD, although other EV types can also cause severe complications. Potential virulence or phenotype-associated sites were identified in the genomes of CVA6, CVA16, and CVA10.