| ObjectiveTrichinella spiralis muscle larva excreted secretion antigen(ES)was used as the diagnostic antigen,for detecting serum IgG and IgM against Trichinella spiralis in mice by ELISA.This method was used to carry out seroepidemiology survey in the crowd of non-remunerated blood donors.MethodsThe muscle larva antigens of Trichinella spiralis were collected and the standard curve of protein quantification was drawn to measure the concentration of extracted antigens.The chessboard titration method was used to select the appropriate concentration of antigen,the dilution of antiserum and the enzyme conjugate,and other optimal reaction conditions to establish the ELISA detection methods for IgM and IgG antibodies,respectively.Serum of 50 mice infected with Trichinella spiralis and 50 normal mice were tested to evaluate the detection effect of this method,as well as its sensitivity,specificity and repeatability.We also establish the method of ELISA to detectet the antibodies in serum of people,and the checkerboard titration was used to select the optimal reaction conditions.The serum of 5,836 nonremune-rated blood donors was used as samples to detect the anti-Trichinella spiralis antibody in human serum by the established ELISA method,and the positive rate and epidemiological information were obtained.ResultsThe results of ELISA for antibody detection.1)General parameter optimization:the sealant was 5%skim milk powder,and the chromodeve-loping agent tetramethy-lbenzidine concentration was 0.4g/L.The reaction time of serum primary antibody,enzymelabeled secondary antibody and substrate chromogenic reaction were 60min,30min and 30min respectively.2)The test IgG parameter of rat Trichinella spiralis:ES antigen coating concentration is 1?g/ml,the optimal dilution of the tested serum is 1:100,and the dilution of goat anti-mouse IgG enzyme-labeled antibody is 1:6000.The critical value Cut off=0.21.There were no false positives in the specific experi-ment,the repeatability was less than 15%,the accuracy was 100%,and the sensitivity reached 1:3200.3)IgM parameters of trichinella mouse were as follows:ES antigen coating concentration was 1.0 ?g/ml,serum dilution was 1:100,and Goat antimouse IgM enzyme labeled antibody dilution was 1:2500.Critical value Cut off=0.25.4)the optimal IgG parameters for human trichinella trichinella were as follows:ES anti-gen coated concentration of 0.77 ?g/ml,sheep anti-human IgG enzyme labeled anti-body concentration of 1:2000,serum dilution of 1:20,critical value Cut off=0.16.The epidemiological survey result in blood donors is as follows.Among the 5,836 blood donors in Zhengzhou,59 person's result were positive for trichinella spiralis antibody detection,with a positive rate of 1.01%.The positive rate of trichi-nella spiralis antibody in different regions was statistically significant(x2=20.718,P=0.036).The positive rate of trichinella spiralis antibody in Guancheng district was the highest(2.69%),while that in Xinmi city was the lowest(0.38%).There was a statistically significant difference in the antibody positive rate of trichinella spiralis in different age groups(x2=21.584,P=0.001).The highest antibody positive rate of trichinella spiralis is in the age group which between 36 and 45 years old which was 1.69%(26/1538),and the lowest was 0.32%(3/938)in the 18-25 years old group.The positive rate of trichinella spiralis antibody was 1.55%(50/3226)in the age group over 36 years,and 0.35%(9/2610)in the age group under 36 years.Male trichinella spiralis antibody positive rate of 1.18%(50/4254)was higher than female trichinella spiralis antibody positive rate of 0.57%(9/1582),the difference was statistically sig-nificant(?2=4.238,P=0.038).There was a statistically significant difference in the antibody positive rate of trichinella spiralis between different educational back-grounds(?2=12.163,P=0.033),with the highest antibody positive rate of trichinella spiralis among primary school students(2.41%)and the lowest among undergrad-duates(0.33%).There was a statistically significant difference in the antibody positive rate between different occupations(?2=40.456,P=0.001).The highest antibody positive rate was 3.37%(28/831)for farmers,and the lowest was 0.21%(1/467)for medical workers.There was no signifycant difference in the positive rate of trichinella spiralis between the whole blood and platelet groups(?2=0.204,P=0.651).The positive rate of trichinella spiralis antibody was higher when eating raw or half raw meat occasionally than when eating no raw or half raw meat(x2=32.198,P=0.001).The positive rate of trichinella spiralis antibody was higher in the non-separate users than in the separate users(x2=20.574,P=0.001).Conclusion1.Successfully established an ELISA method to detect mouse serum Trichinella spiralis IgG and IgM antibodies and blood donor Trichinella spiralis IgG antibodies,by increasing the concentration of TMB chromogen,reducing the amount of ES antigen coating,thereby improving its sensitivity and specificity This method is not only suitable for the diagnosis and epidemiological investigation of trichinellosis,but also can reduce the cost of antibody detection of trichinella spiralis in a large number of blood donors.2.The infection rate of Trichinella spiralis among the blood donors in Zhengzhou belongs to the low prevalence area.The infection rate of people over the age of 36 is higher,the infection rate of males is higher than that of females,and the infection rate of primary school education and farmers is the highest.The infection rate of Trichinella spiralis is also related to poor diet and improper hygiene habits,and health promotion and quarantine prevention and control should be strengthened. |
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