[Epidemiological survey on the infection of hepatitis E virus among pigs in Henan province].

OBJECTIVE: To investigate hepatitis E virus (HEV) infection among pigs in Henan province. METHODS: A total of 623 swine sera, collected from 5 districts, were divided into two groups, under 3-month of age and over 3-month of age. They were tested for HEV antigen and antibody by using ELISAs, respectively. The sera positive for HEV antigen were tested for HEV RNA with RT-PCR. The positive products of RT-PCR were cloned and sequenced. RESULTS: The positive rates of anti-HEV antibody of the groups under 3-month and over 3-month of age were 90.27% and 92.55%, respectively, without statistical difference, while those of HEV antigen were 15.93% and 5.69%, respectively, with significant difference. The positive rates of anti-HEV antibody and HEV antigen were significantly different among different districts. HEV RNA was detectable in 5 of 47 HEV antigen positive samples. The sequence analysis showed that in 4 of 5 specimens the sequence belonged to genotype 4 while in the remaining one the sequence was genotype 1. CONCLUSION: The prevalence rate of HEV infection in pigs was high in Henan province and the rate differed in different districts.

[Evaluation of procleix HIV/HCV RNA diagnostic assay].

BACKGROUND: To investigate the sensitivity and specificity of Procleix HIV/HCV RNA diagnostic assay. METHODS: HIV antibody positive or suspected positive plasmas of blood donors were collected from different provinces and detected with HIV antibody ELISA and HCV antibody ELISA. Samples positive for HIV by ELISA were confirmed by using HIV Blot. All the plasma samples were detected with Procleix HIV/HCV assay, HIV-1 discriminatory assay and HCV discriminatory assay, respectively. RESULTS: All 74 samples positive for both HIV and HCV antibody were positive and 5 samples negative for both HIV and HCV antibody were negative when detected using Procleix HIV/HCV assay; 82 of 84 supplemental HIV antibody positive samples and 6 of 12 supplemental indeterminate samples were positive for HIV RNA, and all 7 HIV antibody negative samples were negative for HIV RNA when detected by using Procleix HIV discriminatory assay. Seventy of 81 HCV antibody positive samples and 4 of 22 HCV antibody negative samples were positive for HCV RNA when detected by using Procleix HCV discriminatory assay. CONCLUSION: This reagent is more sensitive and could be used in blood screening, thereby can reduce both HIV and HCV transmission of blood in window period of HIV and HCV infection.

[A study on the prevalence rates of human immunodeficiency virus, hepatitis B virus and hepatitis C virus infections in intravenous drug users].

OBJECTIVE: To study HIV, HBV and HCV infections in intravenous drug users. METHODS: 2025 blood samples from intravenous drug users were collected from Sichuan, Hunan, Guangxi and Xinjiang regions, and tested for anti-HIV, anti-HCV, HBsAg using enzyme-linked immuno-sobent assays (ELISAs). RESULTS: The positive rates of anti-HIV,anti-HCV and HBsAg were14.7%-30.4%, 60.7%-85.5% and 6.6%-22.4% in the intravenous drug users, respectively. The co-infection rates of HIV/HBV, HIV/HCV, HCV/HBV and HIV/HCV/HBV were 0%-0.4%, 11.6%-27.2%, 2.3%-14.3% and 1.6%-4.8% respectively in this population. CONCLUSION: The infection rates of HIV, HBV and HCV were higher in the intravenous drug users than that in general populations in the same regions, and HIV/HCV co-infection appeared most frequent in this population.

[Establishment of the reference panel for HIV RNA].

OBJECTIVE: To establish a national reference panel for HIV RNA diagnostic reagents. METHODS: Sera from patients with HIV infection and healthy blood donors were collected and tested for HIV and HCV antibodies and HBsAg by using ELISA. The HIV antibody positive samples with ELISA were confirmed with HIV Blot 2.2 (Genelabs). The quantitative samples for HIV RNA were calibrated with the WHO HIV RNA standard. The stability of the panel was evaluated with acceleration method. RESULTS: After screening and calibration, 8 negative samples, 8 positive samples, 3 quantitative samples, 6 sensitivity samples and 5 samples for linear analysis were composed of the national reference panel for HIV RNA. The convinced international units (IU) for the quantitative samples were obtained by seven independent calibration and the logarithm of international units for the quantitative samples (b1-b3) were less than x +/- s. The results showed that this panel may stabilize for 4 days at 4 degrees C. CONCLUSION: A national reference panel for HIV RNA reagents has been established. It may provide the basis for evaluating HIV RNA diagnostic reagents.

[Capacity of HIV enzyme immunoassay diagnostic kits to detect antibodies against different genotypes of HIV].

OBJECTIVE: To investigate the capacity of commercial HIV enzyme immunoassay (EIA) diagnostic kits to detect antibodies against different genotypes of HIV. METHODS: HIV RNA was detected with RT-PCR from samples positive for HIV antibody. The purified PCR products were sequenced directly and the genotypes of HIV from samples were analyzed. The samples for each genotype of HIV were diluted and the diluted samples were detected with different HIV EIA diagnostic kits. RESULTS: All 20 samples positive for HIV antibody were also positive for HIV RNA; 9 of 20 isolates were genotype B, 9 of them were genotype C or CRF BC, 2 of them were CRF AE. The sensitivity of different HIV EIA diagnostic kits to detect antibodies against different genotypes of HIV was not significantly different. CONCLUSION: The capacity of commercial HIV diagnostic kits to detect antibodies against different HIV genotypes may not be significantly different.