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.     

West Nile virus in Canadian blood donors

BACKGROUND: Blood donation screening for West Nile virus (WNV) RNA by nucleic acid testing (NAT) was implemented in Canada in July 2003, and 14 WNV RNA-positive donations were identified. Samples were screened in minipools of six donations with a WNV assay (TaqScreen, Roche). Two of the donors were identified by single-donor screening that was initiated in the province of Saskatchewan, which had the highest prevalence of WNV in the country, in early September 2003. STUDY DESIGN AND METHODS: The original 14 samples and follow-up samples (2-35 days after donation), available from 13 of the 14 donors were tested with an in-house, real-time, quantitative WNV NAT assay that was specific for WNV. A Health Canada reference reagent was used for calibration. Immunoglobulin M (IgM) and immunoglobulin G (IgG) levels were determined with commercial enzyme-linked immunosorbent assay kits. RESULTS: All donors tested positive for the presence of WNV with the in-house assay. Two donors, 18 and 19, identified by single-donor testing, had extremely low levels of viremia and that could only be detected in 1:38 or 1:39 replicate tests. The titers of the remaining index samples ranged from below log2.8 (the limit of quantitation) to log4.7 NAT detectable units per mL. Three samples, from Donors 17, 18, and 19, were IgM-positive, whereas samples from Donors 18 and 19 were also IgG-positive. The remaining 10 donors with follow-up samples all seroconverted. CONCLUSION: The 14 WNV donor samples detected by routine screening were confirmed as WNV RNA-positive by a WNV RNA-specific in-house assay and by demonstration of seroconversion in 13 of the 14 donors.     

West Nile virus infection transmitted by blood transfusion

BACKGROUND: A patient with transfusion-transmitted West Nile virus (WNV) infection confirmed by viral culture of a blood component is described. A 24-year-old female with severe postpartum hemorrhage developed fever, chills, headache, and generalized malaise after transfusion of 18 units of blood components; a serum sample and the cerebrospinal fluid tested positive for the presence of WNV IgM antibodies. An investigation was initiated to determine a possible association between transfusion and WNV infection. STUDY DESIGN AND METHODS: Blood donors were assessed for recent infection through questionnaires and WNV testing of serum samples. Whole-blood retention segments and untransfused blood components were sent to the CDC to test for the presence of WNV through PCR (TaqMan, Applied Biosystems), IgM ELISA, plaque reduction neutralization testing, and viral culture. RESULTS: Three of 15 available donor retention segments were WNV PCR-positive. WNV was recovered from one associated blood component. The implicated donor was symptomatic near the time of donation; serology confirmed WNV IgM seroconversion. CONCLUSION: Seroconversion of a symptomatic donor, the presence of viral genetic material in an associated whole-blood retention segment, and recovery of WNV from an associated component provides compelling evidence for transfusion-acquired infection. This report has important implications for blood safety.     

HTLV核酸检测平台的建立及其献血者筛查

目的 对无偿献血人群进行HTLV核酸筛查,掌握HTLV在无偿献血人群的感染及分布情况,为血液筛查策略的调整提供依据.方法 在现有血液核酸筛查平台(无偿献血血液HBV/HCV/HIV核酸筛查)的基础上,建立HTLV血液核酸筛查平台,对5 368例献血者进行了HTLV(1+2型)的核酸检测,并对筛查情况进行分析.结果 20...     

The hepatitis C virus genotype and subtype frequency in hepatitis C virus RNA-positive, hepatitis C virus antibody-negative blood donors identified in the nucleic acid test screening program in Poland

BACKGROUND: Since 2002, blood donors in Poland have been tested not only for hepatitis C virus antibodies (anti-HCV) but also for HCV RNA or HCV core antigen. This screening program identifies asymptomatic, recently infected individuals with no anti-HCV (in the "window period"). The aim of this study was to compare HCV genotype and subtype distribution in window-period (wp) donors, anti-HCV-positive donors, and chronic hepatitis C (CHC) patients. STUDY DESIGN AND METHODS: A total of 2.37 million donors were investigated for HCV RNA, and 340,000 for HCV core antigen. HCV genotypes and subtypes were investigated in 50 HCV RNA-positive, anti-HCV-negative donors; in 70 anti-HCV-positive donors; and in 170 CHC patients. Re-questioning of wp donors for probable risk factors was introduced. RESULTS: HCV RNA was detected in 50 donors of 2.71 million (1:54,200) anti-HCV-negative blood donations. Of these 50 donors, 36 percent exhibited Subtype 1b, whereas Subtypes 3a and 4c/d were identified in 40 and 14 percent, respectively. In anti-HCV-positive donors and CHC patients, the frequency of Subtype 1b was significantly higher (75.7 and 85.3%, respectively); in both groups the lower frequency of Subtypes 3a (14.3 and 10.6%, respectively) and 4c/d (4.3 and 1.2%, respectively) was found. The probable source of infection was identified in 9 wp donors. CONCLUSIONS: The frequency of wp donors is 18.5 per 1 million. The unexpected high frequency of Genotype 4 and Subtype 3a and the low frequency of Subtype 1b was observed in wp donors compared to anti-HCV-positive individuals. Additional epidemiologic questioning introduced after HCV RNA detection may help to identify infection source.     

核酸检测技术在献血人员血液筛查中的应用

目的：采取核酸检测（NAT ）技术进行血液筛查,减少由献血者感染“窗口期”及隐匿感染献血引起的疾病传播。方法采用酶联免疫吸附法（ELISA）对54358份献血者标本进行乙型肝炎表面抗原（HBsAg）、人类免疫缺陷病毒抗体（抗-HIV）、丙型肝炎病毒抗体（HCV-Ab）检测,同时用转录介导扩增技术（TMA）进行 HBV-DNA 、HCV-RNA 检测,人类免疫缺陷病毒1型（HIV-1）RNA 核酸检测。结果 NAT 检测阳性 ELISA 检测阴性标本共51份。51份标本有鉴别试验结果的33份,其中32份 HBV-DNA 阳性,1份 HIV-1 RNA 阳性,HIV-1 RNA 阳性的献血者经南京市疾病预防控制中心免疫印迹法确认为 HIV-1疑似阳性（gp160和 p24±）。半年后再次回访该献血者,抽取血样送南京市疾控中心经免疫印迹法确认为 HIV-1阳性（gp160、gp120、p66、p51、gp41、p31、p24、p17＋）。结论 NAT 技术可以减少由献血者感染“窗口期”及隐匿感染献血引起的疾病传播,从而减少输血风险。     

核酸血筛在献血者常规筛查中的应用研究

目的评估核酸检测在大规模临床用血输血传染性指标筛查中的必要性和实用性。方法 ELISA法检测献血者HBsAg,抗-HBV和抗-HCV,以及抗-TP,非反应性标本再用国产HBV/HCV/H IV核酸检测试剂进行检测,从中筛查出ELISA检测非反应性,核酸检测阳性的标本。进一步对NAT阳性标本跟踪采样检测以确认血清学转化,或用进口核酸试剂复核检测确认核酸阳性。结果使用8份混样、阳性标本汇集池一次拆分的自动化检测模式,55 499人份ELISA检测合格的血标本中共检出11份HBV核酸阳性标本,1份HCV核酸阳性标本。其中3份经跟踪采样检测确认为HBV感染窗口期标本,1份由罗氏试剂复核检测确认为HCV感染窗口期标本。其余8份HBV核酸阳性样本经"两对半"检测确认为现行ELISA血筛漏检的HBV隐匿性感染或其它感染类型标本。结论核酸血液筛查可大大提高血液安全性,特别是提高对我国较为复杂的HBV低滴度感染标本的检出能力。     

West Nile virus infection in blood donors in the New York City area during the 2010 seasonal epidemic

BACKGROUND: A uniform threshold strategy for converting from minipool (MP)‐nucleic acid testing (NAT) to individual donation (ID)‐NAT screening for acute West Nile virus (WNV) infection among blood donors is lacking. We report on WNV screening at the New York Blood Center during the 2010 seasonal WNV epidemic, the most severe epidemic in that state since the original outbreak in 1999. STUDY DESIGN AND METHODS: Between July 1 and October 31, 2010, blood donations were screened by MP‐NAT or ID‐NAT and the presence of anti‐WNV immunoglobulin (Ig)M and IgG was evaluated among NAT‐positive donations. RESULTS: Twenty presumed viremic donations were identified for a frequency of 0.0129% (1 in 7752 donations). Nine donations that could have been missed by MP‐NAT were identified. Two of these donations were both IgM and IgG negative, one of which would have been missed if more than one positive donation was required for initiating ID‐NAT. Retrospective ID‐NAT revealed two positive donations. The majority of the NAT‐positive donations in New York (16/19) were from donors who lived in counties that had the highest incidence of human WNV cases in the state. CONCLUSION: Our data details the identification of WNV NAT‐positive blood donations during a severe seasonal epidemic in the New York area. By initiating ID‐NAT after one positive donation, using retrospective testing, and triggering ID‐NAT regionally, we were able to prevent the release of presumably infectious donations. The detection of NAT‐positive donations with retrospective testing, however, may indicate the need for changes in our trigger criteria.     

血筛用酶联免疫吸附试验与核酸检测互补性探讨和研究

目的为了提高临床输血的安全性，探讨核酸检测（NAT）与酶联免疫吸附试验（EuSA）技术在血液筛查工作中的互补特性。方法对2007年6月至2008年3月采集的无偿献血者标本共计45022例用ELISA血清学检测方法对血液传染性指标HBsAg、抗-HCV、抗-HIV、梅毒螺旋体、丙氨酸氨基转移酶（ALT）进行检测，各项指标均正常的标本用NAT技术检测，以研究2种检测方法的互补性。结果45，022例标本中血清学检测及ALT不合格人数共计803例，不合格率为1．98％。对各项检测指标合格的36806例标本进行核酸检测，结果HBV-DNA呈阳性3例。HBV-RNA、HIV-RNA均未检出。结论NAT与ELISA的血液筛查检测互补作用主要体现在3个方面：1）病理生理过程互补，检测窗口期的长短主要由检测对象的生理属性来决定，而非检测方法缺陷。2）检测方法学互补，由于检测方法学的不同使得NAT技术的检测灵敏度明显高于ELISA血清学检测方法。3）影响各自实验的错误发生各不相同。     

合肥地区无偿献血者核酸检测的应用研究

目的：探讨核酸检测（NAT）在血液筛查中的作用,为选择血液筛查策略提供科学依据。方法该中心在2012年1月至2013年4月对68662例无偿献血标本同步进行血清学和核酸检测;29例血清学阴性 HBV DNA 阳性样本进行乙型肝炎血清标志物测试;部分抗 HIV 阳性样本送疾控中心做确认实验。结果68662例标本中核酸单独阳性样本120例,输血残余风险为0．175％;乙型肝炎血清标志物检测,以 HBcAb 阳性模式居多;HIV 确认阳性11例,全部为核酸阳性标本。结论核酸检测能够降低输血残余风险,保证输血安全。NAT 和血清学检测相互补充,不能替代,应选择适合的筛查策略。