Recombinant Enterovirus 71 VP1 [GST]

Enterovirus 71 (EV71) is one of the most common pathogens of hand, foot, and mouth disease (HFMD). A rapid reverse transcription recombinase polymerase amplification (RT-RPA) assay was established to detect EV71 subgenotype C4 (EV71-C4). The 95% detection limit of the RT-RPA was 3.767 log10 genomic copies (LGC)/reaction. The specificity was 100%. In a clinical sample evaluation, this approach demonstrated sufficient clinical performance when compared with a commercial RT-qPCR diagnostic kit. Thus, the RT-RPA assay may be a promising alternative for the detection of EV71-C4.

Enterovirus 71 (EV71) and coxsackievirus A16 (CVA16) have been considered major pathogens of hand, foot and mouth disease (HFMD) throughout the world for decades. In recent years, coxsackievirus A6 (CVA6) and coxsackievirus A10 (CVA10) have raised attention as two other serious pathogens of HFMD. The present study focused on the synonymous codon usage of four viruses isolated from 2008 to 2015, with particular attention on P1 (encoding capsid proteins) and P2-P3 regions (both encoding non-structural proteins) in the genomic RNA. Relative synonymous codon usage, effective number of codons, neutrality and correspondence were analyzed. The results indicated that these viruses prefer A/T at the third position in codons rather than G/C. The most frequent codons of 4 essential and 2 semi-essential amino acids, as well as a key amino acid of metabolic junctions (Glu) used in the four viruses are also the most frequently used in humans. Effective number of codons (ENC) values indicated weak codon usage bias in all the viruses. Relatively, the force of mutation pressure in the P1 region was found to be stronger than that in the P2-P3 region, and this force in the P1 region of CVA6 and EV71 was stronger than that of CVA10 and A16. The neutrality analysis results implied that mutation pressure plays a minor role in shaping codon bias of these viruses. Correspondence analysis indicated that the codon usage of EV71 strains varied much more than that of other viruses. In conclusion, the present study provides novel and comparative insight into the evolution of HFMD pathogens at the codon level. (C) 2017 Published by Elsevier B.V.