Recent HIV Infection Detection In Sichuan 2006 IDU Sentinel Surveillance By BED-CEIA

BED-CEIA is a kind of quantificational ELISA. The micro-hole isenveloped by goat-to-man Ig-G, to capture the HIV-1 antibody and non-HIVantibody. According to the level of IgG in serum, which is delegated by therelatively amount of HIV and non-HIV antibody, the proportion of HIV-1 IgGto total IgG can be got indirectly. By which, the rough infection time can bededuced, and the question of whether infected recently can be answered.The main steps of this method include:1 Dilute the samples and antitheses 100 times. The antitheses include HIVstrong positive, weak positive, negative, and standard.2 Diluted samples and antitheses be added in micro-holes, after incubated1 hr 37℃, wash plate.3 HIV biotin-antigen peptide is added in the washed micro-hole plate, afterincubated 1 hr 37℃, wash plate. The biotin-antigen peptide is comprised by B,E, and D epitopes, which include gp41.4 Peroxid enzyme is diluted, and be added in the washed micro-hole plate,after incubated 90 minutes 37℃, wash plate. 5 TMB substrate is added in the washed micro-hole plate, incubated 15minutes 25℃.6 After 1M/L H₂SO4 is added in the holes to stop reaction, OD can bedetected by automatic ELISA apparatus in 450nm (referenced 630nm).In order to get the standard quantitative data, standard sample of the kitwas used, with whose OD, we can get the standard ODs of negative,weak-positive, and strong-positive samples. In addition, 3 parallel holes aredesigned both in screening and determine test, and the median is used incalculation. By this way, the occasional mistakes can be depressed. BED-CEIAhas two steps: screen and determine, with same principle and operationalprogress. The aim also is enhancing veracity, and avoiding mistakes. Thecharacters of BED-CEIA also including:1 the serum needs to be diluted 100 times. As long as the ratio of HIV-1IgG to total IgG keeps steady, the result can be a little affected by dilution.2 The dilution is designed well, so the accuracy is good.3 The gp41 antigen, coming from several HIV-1 sub-types, is used todetect different sub-type antibodies, and the "window period" is similar.4 The equal standards (for example cutoff, window period, and so on) usedin the BED-CEIA make it be possible, that method can be used severalsub-types.For individuals, there would be some fake negative and positive, but forgroups, the mistakes can be counteracted. So this study can just be used forepidemiologic research in groups. It is not proper for individual diagnoses.In this study, a method—BED-CEIA is used to measure the HIV-1 recentinfection in high risk groups. It can fetch up the blank of the study on HIV incidence of our nation, as well as Sichuan Province. The samples come fromSichuan 2006 IDU sentinel surveillance. In this study, BED-CEIA is used todetect the recent injection of HIV positive samples in 2006 IDU sentinelsurveillance. The result show that infection rate of Sichuan IDU sentinelsurveillance is 12.04%, recent infection rate (incidence rate) is 1.36%, yearrecent infection rate (year incidence rate) is 3.19, and it's CI is 4.12%～2.26%.With the epidemic data, it can be decided that the recent infection rate of IDU inSichuan is still in a relative high level. The intervene measures andpropagandize measures are still needed to be strengthen.