献血者中SEN病毒部分基因的克隆和序列分析

目的　了解我国献血者中是否存在SEN病毒 (SENV)感染 ,并分析SENV国内分离株的部分基因序列。方法　根据SENVORF1区保守序列设计引物 ,采用套式PCR方法 ,从献血者血浆标本中分离SENV基因片段 ,对分离的DNA片段进行基因重组和核苷酸序列分析。结果　从 32 9名献血者中分离出 6株SENV基因片段 ,其核苷酸推导氨基酸序列与SENVA～H基因型序列比较 ,同源性在 5 2 %～ 10 0 % ;系统进化树分析发现 ,分离的 6株SENV属SENV H基因型。结论　国内献血者中存在SENV H基因型感染 ,输血可能成为传播SENV途径之一。     

献血人群中SEN病毒感染的检测分析

目的：了解国内献血人群中一种新的比血传播病毒（SENV）感染的流行状况，方法：以SENV ORF1区核苷酸序列设计引物建立套式聚合酶链反应（nPCR）方法。采用多重PCR法对596份严自3个不同地区无偿和／或有偿献血标本进行SENV DNA（D和H亚型）检测，并对PCR阳性产物进行克隆后测序分析。结果：在体检合格的献血中，SENVDNA检出率为13．5％－21．0％在抗－HCV，HBsAg，抗－HIV，梅毒抗体阳性和ALT异常升高的献血中，SENV DNA检出率分别为35．0％、14．0％，60．0％、28．6％和31．3％，献血中SENV－D亚型等高于SENV－H亚型，不同地域献血SENV DNA检出率的差异无显性（P＞0．05），体检不合格献血（抗－HIV或抗－HCV阳性的SENV－D感染率显高于正常献血人群（P＜0．05）；6份严自不同个体和不同地域之间的SENV分离株部分基因组核苷酸的变异最高达11．9％，与标准标（AX025838）相比变异高达13．2％，结论：在国内献血人群中存在SENV感染。     

Occult hepatitis B virus infection in Thai blood donors

BACKGROUND: An evaluation by the National Blood Center, the Thai Red Cross Society, of two commercial multiplex nucleic acid tests (NATs; the Chiron PROCLEIX ULTRIO test and the Roche Cobas TaqScreen MPX test) for screening Thai blood donors for hepatitis B virus (HBV), hepatitis C virus, and human immunodeficiency virus Type 1 identified 175 HBV NAT–reactive/hepatitis B surface antigen (HBsAg)‐negative donors. The classification of the HBV infection of these donors was confirmed by follow‐up testing. STUDY DESIGN AND METHODS: Index samples were tested for HBV serologic markers and HBV viral loads were determined. Donors were followed for up to 13 months and samples were tested with both NAT assays and for all HBV serological markers. RESULTS: Of 175 HBV NAT–yield donors, 72 (41%) were followed. Based on the follow‐up results, the majority of donors who were followed had an occult HBV infection (66.7%), followed by donors with a primary, acute infection (26.4%). The majority of donors in this latter group (20.8%) were in the window period. Three donors (4.2%), who were anti‐HBs positive, had a reinfection or breakthrough infection. CONCLUSION: The majority of donors detected during routine screening, who were HBsAg negative and NAT reactive, had an occult HBV infection, thus validating the decision to introduce NAT for blood donations in Thailand.     

献血者中TT病毒检测及其致病性探讨

目的　探讨TT病毒 (TTV)在输血过程中的传播及其致病性。方法　常规酚 氯仿法抽提血清病毒DNA ,设计位于TTVORF1保守区的两对引物 ,套式PCR扩增病毒DNA。ELISA检测血清HBsAg、抗 HAV、抗 HCV和抗 HIV。结果　健康献血者血清中TTV DNA检出率为 4 3 1 % (96 / 2 2 3)。受血者输血TTV DNA阳性血后 2周 ,血清TTV DNA转阳率为 6 3 6 % (1 4 / 2 2 )。 8周血清TTC DNA阳性率仍为 4 6 4 % (1 0 / 2 2 ) ,其中两对献血者和受血者之间血清TTV DNA同源性达 1 0 0 %。上述 2 2名受血者输血 2周后血清ALT、TB和DB正常 ,血清HBsAg、抗 HAV、抗 HCV和抗 HIV均阴性。随访其中 5例至 8周 ,无肝炎症状及体征 ,血清肝功能正常。结论　TTV可通过血液传播 ,但无明显致病性     

闽南地区无偿献血者隐匿性乙型肝炎病毒感染研究

目的研究闽南地区无偿献血者中隐匿性乙型肝炎病毒感染(OBI)情况,探讨现有输血传播乙肝病毒(HBV)的检测方法的有效性。方法依据多种与HBV相关血清学指标的检测情况对献血者标本进行HBV携带风险评价分级,对较高携带风险的标本做单份多区段巢式-PCR检测其HBV DNA,对低携带风险的标本做10份混合的巢式-PCR检测。采用这一方案,对闽南地区19 360例HBsAg阴性的无偿献血者标本做检测分析。结果闽南地区HBsAg阴性献血者中的HBV DNA阳性检出率为0.21%(40/19 360,95%CI:0.15%—0.28%),属于OBI;其中抗-HBc阳性检出率85%(34/40),但阳性预测值仅为3.4%(34/995,95%CI:2.4%—4.7%);HBV NRAg阳性预测值30%(6/20),但灵敏度为15%(6/40)。结论现有筛查体系下无偿献血者中仍存在一定比例的OBI,需要寻求更为有效的检测方法。     

献血员中人类T淋巴细胞白血病病毒感染的检测

目的：了解人类T淋巴细胞白血病病毒（HTLV）流行献血员中HTLV感染情况,方法：对福建莆田沿海地区献血员2339份血标本,以国产双抗原夹心法进行酶联免疫吸附法（ELISA）试剂盒的筛选,对ELISA阳性血清均用蛋白印迹试验和(或）聚合酶链反应（PCR）结合序列测定进行确证。结果：2339份献血员血标本中,确证阳性9份,均为HTLV－Ⅰ感染,结论福建莆田沿海地区献血员中,HTLV感染率为0．38％。     

SEN virus infection in patients on peritoneal dialysis.

BACKGROUND: Many reports have demonstrated SEN virus (SEN-V) infection rates in hemodialysis patients, but the SEN-V infection rate in peritoneal dialysis (PD) patients has never been reported. In this study, we determined the prevalence rate of SEN-V viremia in a PD population. METHODS: Serum samples from 47 PD patients and a control group of 43 subjects from the general population at their health examination were assayed for SEN-V-D and -H viremia using polymerase chain reaction. RESULTS: The proportions of female gender (p = 0.001), previous transfusion (p < 0.0001), and higher mean serum AST level (p = 0.012) were significantly higher in PD patients. The prevalence rates of SEN-V-D and/or -H viremia were not significantly different between PD patients and controls (27.7% vs 32.6%). SEN-V-D(+) patients had lower mean duration of PD than SEN-V(-) patients. Mean ALT level was significantly lower in SEN-V-H(+) than in SEN-V(-) patients (12.8 +/- 5.8 vs 19.6 +/- 12.1 (IU/L), p = 0.025). None of the SEN-V-infected PD patients had overt clinical or biochemical signs of liver disease. There were no statistically significant differences in prevalence of SEN-V-D and/or -H viremia between automated PD (APD) patients and continuous ambulatory PD (CAPD) patients. CONCLUSIONS: These results indicate that the SEN-V infection rate is not different between healthy individuals and PD patients. Infection with SEN-V is not associated with evident liver disease in PD patients and SEN-V infection rate is not different between APD patients and CAPD patients.     

Prevalence and genetic heterogeneity of SEN virus genotypes D and H in blood donors from Central and Western Europe and West Africa

Objectives: To establish prevalence and phylogenetic relationship of SEN virus (SENV) D and H in blood donors from Scotland, Czech Republic and Ghana. Aim: To compare the data between three regions with differing prevalence of blood‐borne viruses. Background: Anelloviruses are a ubiquitous group of viruses without a clear disease association. Although there is little evidence that they are pathogenic per se, they may have the ability to modify ongoing disease processes. They have a high degree of heterogeneity both within populations and across geographic regions. Materials and Methods: Three sets of donor samples were analysed by nested polymerase chain reaction (PCR) and hybridisation. A proportion of amplified samples were sequenced and phylogenetic analysis was carried out. Results: The prevalence figures (including mixed D + H infection) were established for SENV D: 1·0, 8·4 and 25·2% and H: 12·5, 34·8 and 61·0% in Scottish, Czech and Ghanaian blood donors, respectively. The compilation of prevalence figures indicates the changing ratio of SENV D/H in west‐east direction, most obvious between Western Europe (D/H < 1) and far East Asia (D/H > 1). Phylogenetic analysis grouped the samples mostly in accordance with geographic origin, despite the variability of short sequence analysed. The previously indicated link between SENV prevalence and age was statistically significant in this study, only for SENV H in Czech samples. Conclusion: SENV D and H appear to reflect the incidence of other blood‐borne viruses in these locations. SENV H prevalence of 45·4% in Ghana represents the highest single‐SENV‐genotype prevalence described in blood donors to date.     

Quantitative and genotypic analysis of TT virus infection in Chinese blood donors

BACKGROUND: The TT virus (TTV) is a member of a newly described family of human viruses related to the C ircoviridae viruses. Its association with specific diseases has not been established, and screening of blood donors has not been implemented. To date, 16 genotypes have been identified. STUDY DESIGN AND METHODS: Sera from 471 healthy blood donors (aged 11-58 years) were randomly selected and tested for TTV by the use of two sets of primers: NG59d/NG61d/NG63d primers and T801/T935 primers. Quantitative competitive PCR (QC-PCR) was developed to measure the TTV DNA concentration among the blood donors. Sequencing of a part of the genome was performed to identify the various genotypes. Several samples showed a mixed genotype infection. RESULTS: TTV was detected in 251 (53.3%) of 471 healthy Hong Kong blood donors by the use of NG59d/NG61d/NG63d primers. The prevalence of the virus increased steadily with age (p = 0.03). TTV DNA was detected in 90 percent (90 of a randomly selected 100) of samples by the use of T801/T935 primers. TTV DNA concentration was also measured by QC-PCR in the blood donors who were positive for TTV DNA in the first round of the heminested PCR. TTV titers ranged from 4.8 x 10(2) copies per mL to 6 x 10(4) copies per mL, with a median value of 1.2 x 10(4) copies per mL. Sequencing and phylogenetic analysis of a 223-bp fragment from open reading frame 1 showed three main genotypes (G1 [60.7%], G2 [24.3%], and G3 [14%]) and a new genotype 17 (G17), with the latter bearing 60-percent nucleotide homology with other genotypes deposited at GenBank. In addition, a new TTV subtype, G2f, was found. CONCLUSION: The prevalence of TTV is high in healthy Chinese blood donors. Three main genotypes (G1, G2, and G3) were detected. In addition, a new TTV genotype, tentatively designated as G17, and a new subtype, G2f, were identified.     

Self-reported symptoms associated with West Nile virus infection in RNA-positive blood donors

BACKGROUND: In 2003, West Nile virus (WNV) nucleic acid amplification testing (NAT) was implemented to detect potentially infected donors. Of more than 5.3 million donations screened prospectively by the American Red Cross during the epidemic periods of 2003 and 2004, 974 were NAT-reactive and 519 confirmed-positive. A subset of both the confirmed-positive and the false-positive groups was assessed for demographic characteristics, symptoms, and symptom reporting relative to date of donation. STUDY DESIGN AND METHODS: All donors with initial WNV NAT-reactive results were invited to participate in a study that included a demographic, symptom, and date-of-symptom questionnaire. WNV confirmed-positive cases were compared to false-positive controls for comparison of frequency of symptom reporting before, on the day of, and after donation. RESULTS: Enrolled cases and controls were similar in all characteristics except cases were more likely to live in rural areas. Symptoms were reported by 61 percent of cases versus 20 percent of controls, with 74 percent of symptoms reported by cases within the 14 days after donation. The frequency of headache and fever reported together in the 7 days before donation was not significantly different between cases and controls; only the individual frequencies of headache, eye pain, and new rash during this time were significantly different. The most commonly reported symptoms, after adjustment for symptom reporting by controls, were headache, new rash, and generalized weakness; these symptoms were reported by 25 percent of cases. CONCLUSIONS: The demographic characteristics of infected donors reflected the rural nature of the 2003 to 2004 WNV epidemics. This study suggests that asking donors about predonation headache and fever had no detectable contribution to blood safety.