Analysis on the Result of Virological Surveillance on AFP Cases in Hunan Province from 2006 to 2010

Objective To analyze the results of surveillance for acute flaccid paralysis(AFP) cases in Hunan Province during the period of 2006~2010,and to maintain the polio-free status.Methods All stool specimens from AFP cases from 2006 to 2010 were isolated and identified with L20B and RD cells according to the standard method issued by WHO,and all polio-positive strains were sent to National Polio Laboratory for type determination.Results The indicators of the virological surveillance for AFP cases from 2006 to 2010 were reached the requirement of the Ministry of Health of the People's Republic of China.Totally 2,566 stool specimens collected from 1,291 AFP cases had been examined,the isolated rates of poliovirus(PV) and non-polio enteroviruses(NPEV) were 3.43% and 12.98%,respectively.Among 52 positive specimens,45 were identified as vaccine-variant polioviruses,others were identified as vaccine-related polioviruses,and no polio-wild virus was found.The enteroviruses were isolated all over the years,especially from May to July.The positive cases of poliovirus(PV) covered all the areas of Hunan Province except Xiangtan and Zhangjiajie.There were statistically significant differences in NPEV infection rates among different age groups of AFP cases(P0.01).The isolated rate of PV was descended when the age was increased.There were statistically significant differences in the isolated rate of PV among the AFP cases with different immunization histories(P0.01).The more the OPV immunizations the lower the residual paralysis occurred for AFP cases with PV infection.Conclusions The result of surveillance from 2006 to 2010 indicates that the implementation of polio eradication strategy in Hunan Province is effective and the polio wild virus has been successfully intervened.The target of polio-free is achieved in Hunan Province.But the virological surveillance for AFP cases should be also enhanced on the endgame of poliomyelitis free so as to reach the final goal for the global poliomyelitis eradication.