Non-polio enteroviruses from acute flaccid paralysis surveillance in Shandong Province, China, 1988-2013.

Enteroviruses (EVs) are important human pathogens associated with various clinical syndromes. This study represents an overview of non-polio enteroviruses (NPEVs) isolated from acute flaccid paralysis (AFP) surveillance in Shandong Province, China from 1988 to 2013. Altogether 792 and 170 NPEV isolates were isolated from stool specimens of 9263 AFP cases and 1059 contacts, respectively. Complete VP1 sequencing and typing on all 962 isolates revealed 53 NPEV types in which echovirus (E) 6 (7.6%), E14 (7.6%), E11 (7.4%), coxsackievirus (CV) B3 (7.4%), E25 (5.6%), CVB5 (4.9%), E7 (4.5%) and EV-A71 (4.4%) were the eight most commonly reported serotypes. Distinct summer-fall seasonality was observed, with June-October accounting for 79.3% of isolation from AFP cases with known month of specimen collection. Increase of isolation of EV-A71 and CVA--the predominant pathogens for the hand, foot, and mouth disease--was observed in recent years. Sequence analysis on VP1 coding region of EV-A71 and E6 suggested Shandong strains had great genetic divergence with isolates from other countries. The results described in this study provide valuable information on the circulation and emergence of different EV types in the context of limited EV surveillance in China.