Molecular characterization of echovirus 9 strains isolated from hand-foot-and-mouth disease in Kunming, Yunnan Province, China

Circulating trends of hand, foot, and mouth disease in Hubei Province, China: Impact from the COVID-19 pandemic

Objectives

This study was performed to investigate the effect of non-pharmaceutical interventions on hand, foot, and mouth disease in Hubei Province China during the coronavirus disease 2019 pandemic.

Methods

Data and samples were collected from the hand, foot, and mouth disease surveillance laboratory network in Hubei Province between 2018 and 2022. The samples were identified as Enterovirus A71, Coxsackievirus A6or Coxsackievirus A16 via real-time polymerase chain reaction. Representative Coxsackievirus A6 and Coxsackievirus A16 samples were sequenced and subjected to phylogenetic analyses.

Results

A noticeable 3-fold reduction in the number of hand, foot, and mouth disease cases was observed from 2019 to 2020. The age and sex distributions of patients with hand, foot, and mouth disease were approximately the same from 2018 to 2022. The proportion of Coxsackievirus A6 accounted for 86 % in 2020 and 75 % in 2021 for hand, foot, and mouth disease compared with 48 % in 2018, 53 % in 2019, and 29 % in 2022. The proportions of Coxsackievirus A16 in 2020 and 2021 were 2 % and 17 %, respectively, showing a sharp decline in 2018 (37.8 %) and 2019 (35 %). In 2022, Coxsackievirus A16 was the dominant serotype (46 %). Only slight differences were found in the VP1 sequences across the different years.

Conclusions

Our study confirmed that a series of non-pharmaceutical interventions during the coronavirus disease 2019 period reduced the transmission of enteroviruses and that long-term restrictions could significantly change the prevalence of enterovirus serotypes causing hand, foot, and mouth disease.

Molecular characterization of a novel clade echovirus 3 isolated from patients with hand-foot-and-mouth disease in southwest China

Echovirus 3 (E3) belongs to the species Enterovirus B. Currently, three nearly whole-genome sequences of E3 are available in GenBank in China. In this study, we determined the whole genomic sequences of six E3 strains isolated from the stools of patients with hand-foot-and-mouth disease in Southwest China in 2022. Their nucleotide and amino acid sequences shared 82.1%-86.4% and 96.6%-97.2% identity with the prototype Morrisey strain, respectively, and showed 87.1% and 97.2% mutual identity. The six E3 strains are not clustered with other Chinese strains and formed a novel subgenotype (C6) with the recent American and British strains. Recombination analyses revealed that intertype recombination had occurred in the 2 C and 3D regions of the six E3 strains with coxsackieviruses B5 and B4, respectively. This study augments the nearly whole-genome sequences of E3 in the GenBank database and extends the molecular characterization of this virus in China.

Complete genome analysis of echovirus 30 strains isolated from hand-foot-and-mouth disease in Yunnan province, China

BACKGROUND

Echovirus 30 is prone to cause hand-foot-and-mouth disease in infants and children. However, molecular epidemiologic information on the spread of E30 in southwestern China remains limited. In this study, we determined and analyzed the whole genomic sequences of E30 strains isolated from the stools of patients with hand-foot-and-mouth disease in Yunnan Province, China, in 2019.

METHODS

E30 isolates were obtained from fecal samples of HFMD patients. The whole genomes were sequenced by segmented PCR and analyzed for phylogeny, mutation and recombination. MEGA and DNAStar were used to align the present isolates with the reference strains. The VP1 sequence of the isolates were analyzed for selection pressure using datamonkey server.

RESULTS

The complete genome sequences of four E30 were obtained from this virus isolation. Significant homologous recombination signals in the P2-3'UTR region were found in all four isolates with other serotypes. Phylogenetic analysis showed that the four E30 isolates belonged to lineage H. Comparison of the VP1 sequences of these four isolates with other E30 reference strains using three selection pressure analysis models FUBAR, FEL, and MEME, revealed a positive selection site at 133rd position.

CONCLUSIONS

This study extends the whole genome sequence of E30 in GenBank, in which mutations and recombinations have driven the evolution of E30 and further improved and enriched the genetic characteristics of E30, providing fundamental data for the prevention and control of diseases caused by E30. Furthermore, we demonstrated the value of continuous and extensive surveillance of enterovirus serotypes other than the major HFMD-causing viruses.

Genetic Characteristics and Phylogeographic Dynamics of Echovirus

Echoviruses belong to the genus Enterovirus in the Picornaviridae family, forming a large group of Enterovirus B (EV-B) within the Enteroviruses. Previously, Echoviruses were classified based on the coding sequence of VP1. In this study, we performed a reliable phylogenetic classification of 277 sequences isolated from 1992 to 2019 based on the full-length genomes of Echovirus. In this report, phylogenetic, phylogeographic, recombination, and amino acid variability landscape analyses were performed to reveal the evolutional characteristics of Echovirus worldwide. Echoviruses were clustered into nine major clades, e.g., G1-G9. Phylogeographic analysis showed that branches G2-G9 were linked to common strains, while the branch G1 was only linked to G5. In contrast, strains E12, E14, and E16 clustered separately from their G3 and G7 clades respectively, and became a separate branch. In addition, we identified a total of 93 recombination events, where most of the events occurred within the VP1-VP4 coding regions. Analysis of amino acid variation showed high variability in the a positions of VP2, VP1, and VP3. This study updates the phylogenetic and phylogeographic information of Echovirus and indicates that extensive recombination and significant amino acid variation in the capsid proteins drove the emergence of new strains.

Hand, Foot, and Mouth Disease: A Narrative Review

BACKGROUND

Hand, foot, and mouth disease is a common viral disease in childhood. Because the disease has the potential to reach epidemic levels and mortality is high in some countries, early recognition of this disease is of paramount importance.

OBJECTIVE

This purpose of this article is to familiarize pediatricians with the clinical manifestations and management of hand, foot, and mouth disease.

METHODS

A search was conducted in February 2022 in PubMed Clinical Queries using the key term "hand, foot, and mouth disease". The search strategy included all clinical trials, observational studies, and reviews published within the past 10 years. Only papers published in English were included in this review.

RESULTS

Hand, foot, and mouth disease is characterized by a painful oral enanthem and asymptomatic exanthem on the palms and soles. Children younger than 5 years are most commonly affected. Hand, foot, and mouth disease caused by enterovirus A71 is more severe and has a higher rate of complications than that attributed to other viruses such as coxsackievirus A16. Circulatory failure secondary to myocardial impairment and neurogenic pulmonary edema secondary to brainstem damage are the main causes of death. Fortunately, the disease is usually benign and resolves in 7 to10 days without sequelae. Given the self-limited nature of most cases, treatment is mainly symptomatic and supportive. Intravenous immunoglobulin should be considered for the treatment of severe/complicated hand, foot, and mouth disease and has been recommended by several national and international guideline committees. Currently, there are no specific antiviral agents approved for the treatment of the disease. Drugs such as ribavirin, suramin, mulberroside C, aminothiazole analogs, and sertraline have emerged as potential candidates for the treatment of hand, foot, and mouth disease. Vaccination of susceptible individuals in high-risk areas and good personal hygiene are important preventative measures to combat the disease.

CONCLUSION

Familiarity of the disease including its atypical manifestations is crucial so that a correct diagnosis can be made, and appropriate treatment initiated. A timely diagnosis can help avoid contact with the affected individual and decrease the risk of an outbreak.