Objective: To investigate the latent infection caused by enterovirus 71 (EV71) among healthy people in Tianjin and to provide evidence on prevention and control hand-food and mouth diseases (HFMD).
Methods: 1611 sera specimens were collected from healthy people in Tianjin while EV71 antibody was detected by neutralization test, and then the results were analyzed statistically.
Results: For determining positivity, the cut-point was set at 1:4. The positive rate was 66.79% (1076/1611) for EV71 neutralizing antibody. The lowest positive rate was 32.71% in the 0 - 5 age group while the highest rate was 76.67% in the 16 - 25 age group. Significant difference was seen in the positive rates among different age groups. The lowest positive rate (59.05%) was seen in the city areas while the highest rate (72.35%) was seen in the surrounding counties. 5.71% of the people being tested showed their neutralizing antibody as ≥ 1:256. The difference was statistically significant on positive rates among different areas. We constructed logistic regression models with the EV71 neutralizing antibody positive rate as the dependent variable and age, sex, floating population, area etc. as independent variables. There appeared statistical significances in all the independent variables.
Conclusion: Age seemed a risk factor for recessive infection of EV71, and the neutralizing antibody against EV71 might not be kept permanently. In order to prevent and control the HFMD, more attention should be paid to the areas where more floating population were resided.