ABSTRACT
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.
ABSTRACT
Strong inhibition of Bacillus subtilis strain NJ-18 on mycelia growth of Alternaria solani was observed in the antagonistic tests by cylinder plate methods, and the inhibition width was 21.5 mm. Observation under microscope found that the supernatant of fermentation from NJ-18 could make the pathogen hyphae cells malformed and swelled, and consequently the growth of the pathogen was inhibited. Determining of the colonization in potato plants by the signed rifampicin-resistance in NJ-18 showed that it could colonize well in the plants, the colonization quantity of NJ-18 in the root and stem of the potato detected 30 days after fermentation irrigation was 103 CFU/g plant’s fresh weight. In pot experiment, we inoculated the tomato plants with the spore suspensions of Alternaria solani after spraying the fermentation of NJ-18, the results were investigated in 14 days and the efficacy in controlling the disease was 72.9%, which was significantly higher than 45.7%, the efficacy resulted from spray treatment of 2000 fold dilution of 50% iprodione wetable powder.