ABSTRACT
<p><b>OBJECTIVE</b>To compare the differences between the direct immuno-fluorescent assay (DFA) and real-time quantitative PCR in detecting the Hantavirus (HV) in rat lungs.</p><p><b>METHODS</b>From April to October in 2012, a total of 479 rats were caught by mouse-trap in residential or wild areas in Huxian, Jingyang, and Meixian of Shaanxi province, where haemorrhagic fever with renal syndrome (HFRS) was highly prevalent. The rats were dissected to take the two lungs, one was frozen and applied immuno-fluorescent assay to detect HV antigen while the other one was extracted its RNA and detected HV nucleic acid by real-time quantitative PCR. Then we compared the positive rate of the two methods.</p><p><b>RESULTS</b>Out of the 479 rats, 105 were caught from residential areas and the other 374 were caught from wild areas. Among the 105 rats caught from residential areas, no HV were detected out neither by DFA nor by real-time quantitative PCR. Among the 374 wild rats, 13.1% (49/374) were detected HV positive by DFA and 14.7% (55/374) were detected HV positive by real-time quantitative PCR. The difference showed no statistical significance (χ(2) = 0.402, P = 0.526). When detecting each lung sample, the HV positive rate was 10.2% (49/479) under the detection by DFA while the HV positive rate was 11.5% (55/479) under the detection by real-time quantitative PCR. The difference had no statistical significance (χ(2) = 1.286, P = 0.257) and the consistency coefficient was 68.2% under the paired chi-square test analysis, which showed high consistency (u = 11.759, P < 0.05). The sensitivity of real-time quantitative PCR to detect HV was 77.6% (38/49) comparing with DFA as standard, and the specificity was 96.1% (413/430). Out of the 9 suspected HV positive sample detected by DFA, 6 were confirmed positive by real-time quantitative PCR and 3 were denied.</p><p><b>CONCLUSION</b>Compared with the DFA, real-time quantitative PCR could also be used to detect the infection of HV in rats, and the result might be more stable.</p>
Subject(s)
Animals , Rats , Fluorescent Antibody Technique, Direct , Orthohantavirus , Hemorrhagic Fever with Renal Syndrome , Epidemiology , Lung , Virology , Real-Time Polymerase Chain ReactionABSTRACT
Objective To evaluate the protective rate and the variation of HFRS-IgG on hemorrhagical fever with renal syndrome (HFRS) vaccine.Methods Cluster,random sampling and cross-sectional study were used to assess the protective rate of HFRS vaccination.Level of HFRS-IgG was detected with ELISA in epidemic and non-epidemic areas of HFRS.Results Curve equation was obtained as Yprocective rate=(0.863+0.283/Xvaccination term) × 100％ by protective rate with vaccination term.Protective rates showed a reducing trend,90％ after 7-8 years of vaccination,88％ after 10 years,and 94％ on average.Absorbance (A) value of HFRS-IgG was 4 times higher in persons with vaccination than those without,in the epidemic area.Higher antibody level could be obtained after primary vaccination,but the level of antibody had a 50％ reduction after 5-10 years of vaccination,and a 60％ reduction after 10 years of vaccination.Conclusion HFRS antibody had a 50％ reduction after 5-10 years of vaccination.The protective rate of HFRS vaccination had a 90％ loss,after 7-8 years of vaccination.Booster dose was necessary after 7 years of vaccination.