Phylogenetic analysis and development of an immunofluorescence assay for untypeable strains of coxsackievirus B3

Two Natural Recombination gave rise to the Coxsackievirus B3 GV that triggered outbreaks in China in 2006 - 2012

Coxsackievirus B3 serotype GV caused the epidemic of Coxsackievirus B3 infection in China from 2006 to 2012. To study the evolution and recombination of Coxsackievirus B3 serotype GV, we performed recombination and phylogenetic analysis of 499 complete genomes of Enterovirus B available in GenBank, dated April 2019. Results indicated that most of the strains of Coxsackievirus B3 GV in P1 region were derived from a Coxsackievirus B3 GVI parent, and in P2-3 region from EchoV E25 strain, with nucleotide identities of 97.2% and 94.7%, respectively. Other strains of Coxsackievirus B3 GV-C1 in P1-P2 regions were derived from Coxsackievirus B3 GV-C3, whereas those in P3 regions were from CVB5. These naturally occurring recombination events were confirmed by phylogenetic analysis. This study indicates that two naturally occurring recombination gave rise to the coxsackievirus B3 GV that triggered outbreaks in China in 2006 - 2012.

Two Coxsackievirus B3 outbreaks associated with hand, foot, and mouth disease in China and the evolutionary history worldwide

BACKGROUND

Coxsackievirus B3 (CV-B3) is usually associated with aseptic meningitis and myocarditis; however, the association between CV-B3 and hand, foot, and mouth disease (HFMD) has not been clearly demonstrated, and the phylogenetic dynamics and transmission history of CV-B3 have not been well summarized.

METHOD

Two HFMD outbreaks caused by CV-B3 were described in Hebei Province in 2012 and in Shandong Province in 2016 in China. To analyze the epidemiological features of two CV-B3 outbreaks, a retrospective analysis was conducted. All clinical specimens from CV-B3 outbreaks were collected and disposed according to the standard procedures supported by the WHO Global Poliovirus Specialized Laboratory. EV genotyping and phylogenetic analysis were performed to illustrate the genetic characteristics of CV-B3 in China and worldwide.

RESULTS

Two transmissible lineages (lineage 2 and 3) were observed in Northern China, which acted as an important "reservoir" for the transmission of CV-B3. Sporadic exporting and importing of cases were observed in almost all regions. In addition, the global sequences of CV-B3 showed a tendency of geographic-specific clustering, indicating that geographic-driven adaptation plays a major role in the diversification and evolution of CV-B3.

CONCLUSIONS

Overall, our study indicated that CV-B3 is a causative agent of HFMD outbreak and revealed the phylogenetic dynamics of CV-B3 worldwide, as well as provided an insight on CV-B3 outbreaks for effective intervention and countermeasures.