Development of a Rift Valley fever virus viremia challenge model in sheep and goats

Rift Valley fever virus (RVFV), a member of the family Bunyaviridae, causes severe to fatal disease in newborn ruminants, as well as abortions in pregnant animals; both preventable by vaccination. Availability of a challenge model is a pre-requisite for vaccine efficacy trials. Several modes of inoculation with RVFV ZH501 were tested on goats and sheep. Differences in development of infectious viremia were observed between animals inoculated with RVFV produced in mosquito C6/36 cells compared to Vero E6 cell-produced inoculum. Only C6/36-RVFV inoculation led to development of viremia in all inoculated sheep and goats. The C6/36 cell-produced RVFV appeared to be more infectious with earlier onset of viremia, especially in sheep, and may also more closely represent a field situation. Goats were somewhat more resistant to the disease development with lower and shorter infectious virus viremia, and with only some animals developing transient increase in rectal temperature in contrast to sheep. In conclusion, a challenge protocol suitable for goat and sheep vaccine efficacy studies was developed using subcutaneous inoculation of 10⁷ PFU per animal with RVFV ZH501 produced in C6/36 cells.     

Analytical characterization of an assay designed to detect and identify diverse agents of disseminated viral infection

BackgroundDiverse viruses often reactivate in or infect cancer patients, patients with immunocompromising infections or genetic conditions, and transplant recipients undergoing immunosuppressive therapy. These infections can disseminate, leading to death, transplant rejection, and other severe outcomes.ObjectivesTo develop and characterize an assay capable of inclusive and accurate identification of diverse potentially disseminating viruses directly from plasma specimens.Study designWe developed a PCR/electrospray ionization mass spectrometry (PCR/ESI-MS) assay designed to simultaneously detect and identify adenovirus, enterovirus, polyomaviruses JC and BK, parvovirus B19, HSV-1, HSV-2, VZV, EBV, CMV, and herpesviruses 6–8 in plasma specimens. The assay performance was characterized analytically, and the results from clinical plasma samples were compared to the results obtained from single-analyte real time PCR tests currently used in clinical practice.ResultsThe assay demonstrated sensitivity and specificity to diverse strains of the targeted viral families and robustness to interfering substances and potentially cross reacting organisms. The assay yielded 94% sensitivity when testing clinical plasma samples previously identified as positive using standard-of-care real-time PCR tests for a single target virus (available samples included positive samples for 11 viruses targeted by the assay).ConclusionsThe assay functioned as designed, providing simultaneous broad-spectrum detection and identification of diverse agents of disseminated viral infection. Among 156 clinical samples tested, 37 detections were made in addition to the detections matching the initial clinical positive results.     

Comparison of Severity of Viremia and Antibody Responses between Infants and Children with Measles

Severity of viremia and neutralizing antibody responses were compared between nine young infants ( 10 months) with measles and 18 infants and children ( 11 months) with ordinary measles. Peripheral blood mononuclear cell (PBMC)-associated viremia was detected between the first day of elevation of fever (day 0) and day 5 of the disease in the former group, whereas PBMC-associated and cell-free viremia were detected between day 0 and day 14 in the latter group. The number of infected PBMC during the first 7 days of the disease was 3.22 ± 1.07 (log₁₀, mean ± s.d.) per 10 million PBMC in the former group, which was significantly smaller ( P = 0.02) than that of the latter group (4.21 ± 1.18). The former group reached the maximum level of antibody earlier than the latter group.     

Long-term follow-up of Epstein-Barr virus viremia in pediatric recipients of renal transplants

The common observation of Epstein-Barr virus (EBV) viremia in pediatric recipients of renal transplants and the occurrence of an EBV-related pulmonary leiomyoma prompted us to intensify the follow-up of EBV infections from 1995 to October 2000. Follow-up included serology and detection of viral DNA in blood using a semi-quantitative nested polymerase chain reaction (PCR) and later a real-time PCR with higher sensitivity. The aim of this study was the early detection of primary infections or reactivations. We obtained 250 samples from 32 patients. EBV DNA detection was consistently negative in 14 patients. There were 5 patients that were considered at risk for post-transplant lymphoproliferative disease, as they were EBV seronegative and were given a kidney from a positive donor. Of these, 4 had at least one episode of high-level EBV viremia. During these episodes, an absence of noticeable symptoms that could be related to EBV was noted for all but 1 patient. This child presented with severe neutropenia 1 month after grafting and, 28 months later, several nodules of pulmonary leiomyoma, which were found to be EBV related. Four episodes of high-level viremia were observed before the discovery of the leiomyoma. Viral DNA detection is important for the follow-up of such patients that are especially at risk of serious complications of EBV infections.     

Impact of Cytomegalovirus Viral Load on Probability of Spontaneous Clearance and Response to Preemptive Therapy in Allogeneic Stem Cell Transplantation Recipients

The optimal viral load threshold at which to initiate preemptive cytomegalovirus (CMV) therapy in hematopoietic cell transplantation (HCT) recipients remains to be defined. In an effort to address this question, we conducted a retrospective study of 174 allogeneic HCT recipients who underwent transplantation at a single center between August 2012 and April 2016. During this period, preemptive therapy was initiated at the discretion of the treating clinician. A total of 109 patients (63%) developed CMV viremia. The median time to reactivation was 17 days (interquartile range, IQR, 7-30 days) post-HCT. A peak viremia ≥150?IU/mL was strongly associated with a reduced probability of spontaneous clearance (relative risk, .16; 95% confidence interval, .1-.27), independent of established clinical risk factors, including CMV donor serostatus, exposure to antithymocyte globulin, and underlying lymphoid malignancy. The median time to clearance of viremia was significantly shorter in those who started therapy at CMV <350?IU/mL (19 days; IQR, 11-35 days) compared with those who started antiviral therapy at higher viremia thresholds (33 days; IQR, 21-42 days; P?=?.02). The occurrence of treatment-associated cytopenias was frequent but similar in patients who started preemptive therapy at CMV <350?IU/mL and those who started at CMV >350?IU/mL (44% versus 57%; P?=?.42). Unresolved CMV viremia by treatment day 35 was associated with increased risk of therapeutic failure (32% versus 0%; P?=?.001). Achieving eradication of CMV viremia by treatment day 35 was associated with a 74% reduction in 1-year nonrelapse mortality (NRM) (adjusted hazard ratio [HR], .26; 95% confidence interval [CI], .1-.8; P?=?.02), whereas therapeutic failure was associated with a significant increase in the probability of 1-year NRM (adjusted HR, 26; 95% CI, 8-87; P?<.0001). We conclude that among allogeneic HCT patients, a peak CMV viremia ≥150?IU/mL is associated with a >80% reduction in the probability of spontaneous clearance independent of ATG administration, CMV donor serostatus, and lymphoid malignancy, and is a reasonable cutoff for preemptive therapy. Delaying initiation of therapy until a CMV value ≥350?IU/mL is associated with more protracted CMV viremia, and unresolved viremia by treatment day 35 is associated with a significant increase in NRM.     

Rotavirus Causes Hepatic Transaminase Elevation

Rotavirus is one of the leading causes of acute gastroenteritis among children. While clinical complaints are generally intestinal including vomiting and diarrhea, there is evidence to suggest that disease outside the gastrointestinal tract occurs. This study examines the frequency of hepatic transaminase elevation in children with rotavirus gastroenteritis. Patients identified with rotavirus gastroenteritis by stool antigen testing between November 2005 and March 2006 had available serum analyzed for alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, total bilirubin, direct bilirubin, and creatinine phoshosphokinase (CPK). Chart review was conducted to identify patients with possible liver injury unrelated to rotavirus. Among the 92 patients identified with rotavirus during the study period, 75 had serum specimens available for testing. Fifteen patients (20%) had elevated ALT and AST, including one patient with an increase in AST, ALT, alkaline phosphatase, and total and direct bilirubin. The mean ALT elevation was 56 IU/L (range, 44 to 114 IU/L), and the mean AST elevation was 80 IU/L (range, 57 to 126 IU/L). Fifty-three patients (71%) had an increase in AST alone, and three patients (4%) had an increase in AST and alkaline phosphatase. The mean AST values in these groups were 61 IU/L (range, 42 to 110 IU/L) and 79 IU/L (range, 59 to 96 IU/L), respectively. In conclusion, rotavirus commonly causes elevation of liver transaminases.     

台州市2017-2018年新报告HIV/AIDS巨细胞病毒血症现患率及影响因素研究

目的:了解2017-2018年台州市新报告且未接受抗病毒治疗（ART）的HIV/AIDS血浆巨细胞病毒血症现患率及其影响因素。方法:收集台州市新报告且未接受ART的成年HIV/AIDS血浆样本,提取核酸后采用荧光定量PCR检测巨细胞病毒DNA水平,采用单因素与多因素logistic回归分析其影响因素。结果:研究对象61...     

输血后肝炎患者HCV感染及其病毒血症的研究

利用血清学ＥＬＩＳＡ方法和ＰＣＲ技术对１６９例输血后肝炎（ＰＴＨ）患者病因学进行了研究。结果表明，ＰＴＨ的主要致病原为ＨＣＶ（９８．２２％），其中部分患者（２４／１６９），同时合并有ＨＢＶ感染，３例ＰＴＨ患者病因仍不明确，ＨＣＶ感染所致ＰＴＨ患者抗ＨＣＶ检出时间为ＰＴＨ症状出现后７ｄ～１年，平均为５４．６２ｄ，ＨＣＶＲＮＡ在感染早期（６～２０ｄ）即可检出，对８４例ＰＴＨ患者１．５年～３年的随访观察     

Heparin-binding and patterns of virulence for two recombinant strains of Sindbis virus

E2 is an important determinant of Sindbis virus neurovirulence. Increased heparan sulfate (HS) binding is associated with rapid clearance of viremia and usually with decreased virulence. However, substitution of histidine for arginine at E2-157 (R157H) or glutamate for lysine at E2-159 (K159E) produces viruses with decreases in heparin-Sepharose binding and increases in viremia but different levels of binding to HS-expressing cells and virulence phenotypes in newborn CD-1 mice (Byrnes, A.P., Griffin, D.E., 2000. Large-plaque mutants of Sindbis virus show reduced binding to heparan sulfate, heightened viremia and slower clearance from the circulation. J. Virol. 74, 644-651). To identify mechanisms of virulence, R157H and K159E were studied in newborn CD-1 and BALB/c mice. Subcutaneous inoculation of R157H caused 100% and K159E 60% mortality in 2-day-old CD-1 mice. R157H caused 25% and K159E no mortality in 2-day-old BALB/c mice. R157H and K159E replicated similarly at the site of inoculation with the same level of viremia, but clearance was slower in CD-1 than BALB/c mice. R157H replicated better than K159E in the central nervous system (CNS) after subcutaneous and intracerebral inoculation and in undifferentiated neurons. These studies show a genetic restriction of replication in newborn BALB/c mice, and that amino acid substitutions affecting binding to proteoglycans may differ in importance for CNS infection and viremia.     

丙型肝炎病毒准种多样性与病毒血症水平、疾病活动度及干扰素疗效的关系

目的　了解丙型肝炎病毒 (HCV)准种变异与病毒血症水平、疾病活动度及干扰素疗效的关系。方法　采用针对HCVE2高变区 1 (HVR1 )的单链构象多态性分析法 (SSCP)对 68例慢性丙型肝炎患者进行HCV准种检测 ,分析准种数目与HCVRNA、ALT、AST水平及肝组织活动指数 (HAI)的相关性。对其中 48例给予干扰素治疗 ,分析准种数目对干扰素应答效果的影响。结果　 61例HVR1SSCP阳性 ,HCV准种数目为 (6 2± 2 4)条。准种数量与HCVRNA水平显著相关 (P <0 0 1 ) ,与ALT、AST及HAI无明显相关 (P >0 0 5)。干扰素治疗患者中 ,43例HVR1阳性 ,持续应答者治疗前HCV准种数量 (3 3± 1 2 ,n =1 1 )显著少于获得治疗终点应答 (ETR)伴复发者 (6 3± 2 2 ,n =1 2 ,P <0 0 5)或无应答者 (8 0± 3 3 ,n=2 0 ,P <0 0 1 )。治疗结束时 ,干扰素组仍有 1 6例检测出HCV准种 ,但准种条数降为 (3 4± 1 2 )条 ,与未接受干扰素治疗病例的准种数目 (6 8± 2 5)相比差异有显著性 ,P <0 0 1 ) ,且其中 1 0例准种模式发生了改变。结论　HCV准种多样性可引起较高的病毒血症水平 ,但与疾病活动度无关 ;准种数目可作为预测慢性丙型肝炎干扰素疗效的指标。