Ulrike Reber

Poor Clinical Sensitivity of Rapid Antigen Test for Influenza A Pandemic (H1N1) 2009 Virus

Influenza A pandemic (H1N1) 2009 virus RNA was detected by reverse transcription–PCR in 144 clinical samples from Bonn, Germany. A common rapid antigen–based test detected the virus in only 11.1% of these samples. The paramount feature of rapid test–positive samples was high virus concentration. Antigen-based rapid tests appear unsuitable for virologic diagnostics in the current pandemic.

Two Cases of Sepsis-Like Illness in Infants Caused by Human Parechovirus Traced Back to Elder Siblings with Mild Gastroenteritis and Respiratory Symptoms

ABSTRACT Sepsis and sepsis-like illness in neonates and infants are serious emergencies. Recently, human parechovirus type 3 (HPeV-3) has been identified as a further etiologic agent of these conditions. We report two unlinked cases of infant HPeV-3 sepsis-like illness whose sources could be traced back to elder siblings with mild gastroenteritis and respiratory symptoms.

Human Parvovirus 4 in Nasal and Fecal Specimens from Children, Ghana

Nonparenteral transmission might contribute to human parvovirus 4 (PARV4) infections in sub-Saharan Africa. PARV4 DNA was detected in 8 (0.83%) of 961 nasal samples and 5 (0.53%) of 943 fecal samples from 1,904 children in Ghana. Virus concentrations ≤6–7 log10 copies/mL suggest respiratory or fecal–oral modes of PARV4 transmission.

Performance of the Novel Qiagen artus QS-RGQ Viral Load Assays Compared to That of the Abbott RealTime System with Genetically Diversified HIV and Hepatitis C Virus Plasma Specimens

ABSTRACT We compared two novel Qiagen QS-RGQ viral load assays with the established Abbott RealTime assays on a highly diversified panel of 121 human immunodeficiency virus (HIV) and 107 hepatitis C virus (HCV) specimens. The quantifications correlated well for all HIV and HCV types, but Qiagen yielded higher HCV concentrations than Abbott, predominantly in genotypes 4 and 5.

Human parvovirus 4 viremia in young children, Ghana.

To the Editor: Establishment of viremia is a characteristic feature of infection with human parvovirus 4 (PARV4). In northern Europe, PARV4 (human partetravirus) is primarily transmitted by blood-borne routes (1,2). In other areas (southern Europe, western Africa, South Africa, Asia) infection seems to be more widespread, suggesting alternative modes of virus acquisition (3–6).

Absence of detection of novel human parvoviruses in German plasma donations

In the August issue of TRANSFUSION, Servant-Delmas and coworkers reported the absence of novel human parvovirus 4 (PARV4), tested by polymerase chain reaction (PCR) in serum or plasma, from 1) a cohort of 78 nonimmunodeficient patients with congenital hemoglobinopathy and having received more than 100 RBC units and from 2) a total of 478 blood donors including 280 healthy donors, 105 donors who tested positive for hepatitis B virus (HBV) surface antigen, and 93 donors testing positive for hepatitis C virus (HCV) antibody. We wish to add our experience from a similar study. Since no information on the prevalence of PARV4 Genotypes 1 and 2, discovered in 2005 and 2006, respectively, and on human bocavirus (HBoV), discovered in 2005, in the German blood donor population is available, we analyzed a total of 775 randomly selected, diagnostic plasma minipools representing 69,632 individual blood donations for PARV4 DNA by PCR. A total of 424 of these pools, representing 37,880 donations, were also analyzed for HBoV DNA. Donations were collected from voluntary donors in Bavaria, Germany, during July 2007 and March 2008. Pools were prepared as described elsewhere. None of the pools contained any HIV-1 PCR-positive donations. Two pools were positive for HBV DNA, and two additional pools were positive for HCV RNA. Additionally, stored nucleic acid extracts from 50 individual donations containing viruses that are transmitted parenterally were analyzed (6 HCV-, 3 HIV-, 15 HBV-, and 26 parvovirus B19– positive samples, respectively). Nested PCR PARV4-II was performed as described previously. PCR sensitivity for pooled blood donations was determined by spiking a PARV4-negative, 96-member plasma minipool with a plasma sample containing a known concentration of PARV4. Eight serial pool dilutions beginning with a dilution representing an individual donation with 2000 copies/mL were prepared. Each dilution was tested by PCR in seven to eight replicate reactions. The lower limit of detection (LOD, >95% diagnostic hit rate as determined by probit analysis) was 1144 copies/mL (95% confidence interval [CI], 720-4231). This corresponded to detection of a projected DNA equivalent of two copies per PCR tube. The recently discovered PARV4 Genotype 3, identified in biopsy tissue from two AIDS patients from sub-Saharan Africa, was also detectable by this assay, at approximately 10-fold reduced sensitivity (own unpublished data). HBoV PCR was performed by a seminested PCR using the primers 188F and 542R (given in Brown and Simmonds) and 188F and NP1R (5′-2579TGTACTCTCCCTCGTCTT CA2560-3′, numbering according to GenBank DQ000495) for the first and second rounds, respectively. Using plasmid-based copies of the PCR target region, the 95% probit LOD of this assay was determined to be 5.8 copies per PCR tube (95% CI, 3.9-14.9 copies/tube). Using these assays in our diagnostic plasma minipools, representing 69,632 and 37,880 individual blood donations, respectively, neither PARV4 DNA nor HBoV DNA was detected. It should be mentioned that the primer binding sites of our HBoV Species 1 assay were unique compared to the recently discovered HBoV Species 2, 3, and 4, suggesting very low probability of coamplification. HBoV Species 2 through 4 have been detected in stool samples only. Up to now, PARV4 viremia was found at highest frequency among intravenous drug users (IDUs) coinfected with HCV or HIV, i.e., in 3 of 10 postmortem blood samples from HCV RNA–positive IDUs from the London area, England, and in 7 of 88 blood samples from IDUs in Thailand, six of whom were coinfected with HCV. Because donations from IDUs are systematically excluded by the donor deferral policy in Germany, the absence of PARV4 in blood donors in our study might be a consequence of donor selection. High frequency of PARV4 viremia was detected in 16-member minipools (29/300) and individual plasma donations (4/200) collected in the Los Angeles area in summer 2005, that is, around the same time and from the same region that yielded the original identification of PARV4. Besides these studies, PARV4 viremia has only been reported in 1 of 100 blood donor sera from northern Italy and in 7 of 176 blood donor sera in Thailand, whereas no positive samples were found in 192 individual donations from southeastern France, as well as in the recent study of Servant-Delmas and colleagues in central France. Besides these findings both PARV4 Genotypes 1 and 2 have been detected by the authors in 4% to 5% of recent manufacturing plasma pools and in 8% to 9% of recently used coagulation factor concentrates. Notably, PARV4 was not distributed equally between the different manufacturers. Based on these observations, and on the frequent detection of PARV4 DNA in autopsy tissue from individuals with a history of parenteral exposure to blood or blood products, it was suggested that PARV4 is primarily or exclusively transmitted via the parenteral route. However, the clinical relevance of PARV4 still remains unclear. Studies on molecular epidemiology revealed remarkably limited sequence diversity of PARV4, especially in Genotype 1, suggesting recent introduction of virus in parenterally exposed populations. Thus, PARV4 distribution may considerably vary over time and geography and between different populations. Our study is limited in that it cannot provide an estimation of the frequency of donations contaminated at viral loads below the PCR LOD (1144 DNA copies/mL). Data concerning PARV4 viral loads in blood are scarce. In the four blood donors from the Los Angeles area PARV4 load was less than 100 copies/mL. However, based on DNA concentrations detected in plasma manufacturing LETTERS TO THE EDITOR

The seroprevalence of parvovirus B19 infection in pregnant women in Sudan.

Parvovirus B19 (B19V) infection during pregnancy may have serious consequences like fetal anaemia, hydrops fetalis, and fetal loss. Since epidemiological data on B19V infection are generally lacking in Sudan, the current study aimed to determine the seroprevalence of B19V in Sudanese pregnant women. Five hundred women, attending antenatal clinics in Khartoum state between November 2008 and March 2009, were enrolled and screened for B19V IgG and IgM antibodies by enzyme immunoassays. The study revealed a B19V IgG seroprevalence of 61·4%, with one subject positive for IgM. B19V DNA was not detected by PCR in any of the tested individuals. B19V IgG seroprevalence was significantly correlated with multigravidity (P = 0·046). Our data showed that B19V infection is prevalent in Sudan and we recommend further studies in Sudanese women, particularly in those with complications and adverse outcomes of pregnancy.

Evaluation of cellulose pads as a method to detect cytomegalovirus DNA in neonatal urine

Background Several approaches exist to screen neonates for congenital cytomegalovirus infection. We here describe a new method using cellulose pads for urine collection and its evaluation in an experimental and a clinical setting. Methods We systematically tested the effect of storage duration of the pads after exposure to cytomegalovirus-positive urine, meconium contamination and specimen handling on the cytomegalovirus load and the detection rate. Further, the method was tested in clinical practice in a cohort of 500 neonates. Results Following exposure of urine pads with cytomegalovirus-positive urine, the viral load decreased after 15 min, 12 h, 24 h, and 7 days to 63.2%, 42.1%, 31.6%, and 9.3% of the baseline value. Cytomegalovirus detection rate after seven days was 100%. Contamination with meconium resulted in a comparable reduction of the viral load. The detection rate for dried urine pads after seven days was 93.3%. In clinical practice, urine collection from pads was successful in 73.6% by the first attempt and in 26.4% by the second attempt. Conclusions Urine collection using cellulose pads seems feasible regardless of a reduction of the cytomegalovirus load due to exposure to the pad itself or to meconium. Drying of the exposed urine pad should be avoided.