Virological surveillance for poliomyelitis in Shanxi, 2014–2018

ObjectiveTo analyze and evaluate result of virological surveillance for poliomyelitis in Shanxi province from 2014 to 2018.

MethodsAccording to the 4th edition of the polio laboratory manual for virus isolation and identification of World Health Organization, the virological surveillance for poliomyelitis was conducted in the acute flaccid paralysis (AFP) cases and contacts in Shanxi during this period, the detection results of stool samples from the AFP cases and contacts were analyzed. The isolated L20B positive strains were identified through intra-typic differentiation. The nucleotide sequencing and analyzing of the capsid protein VP1 coding region of poliovirus were performed by National Polio Laboratory, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention (CDC).

ResultsDuring 2014–2018, Polio Laboratory of Shanxi CDC tested 2 042 stool samples of 927 AFP cases and contacts. A total of 21 poliovirus strains were isolated with the isolation rate of 1.03%, in which 11 were Sabin like strains. 9 were highly variant vaccine strains and 1 was vaccine-derived poliovirus (VDPV) strain. A total of 103 non-polio enterovirus strains were isolated with the isolation rate of 5.04%.

ConclusionThe AFP surveillance system of Shanxi is sensitive. During 2014–2018, no wild poliovirus were found from the stool samples of AFP cases and contacts in Shanxi. The polio-free status was kept in Shanxi.