Increase in human West Nile and Usutu virus infections, Austria, 2018.

Between 28 June and 17 September 2018, 27 cases of human West Nile virus infections were recorded in Austria; four cases of West Nile neuroinvasive disease, 11 cases of West Nile fever, six infections detected by blood donation screening and six imported cases. In addition, 18 cases of human Usutu virus infections (all blood donors) were recorded. This is the highest number of annual infections recorded in Austria since the introduction of both viruses.

Recipients potentially infected with parvovirus B19 by red blood cell products.

BACKGROUND: Since 2000, blood donor screening for parvovirus B19 (B19) by nucleic acid testing (NAT) at the Ulm Institute has been conducted 6 to 8 weeks postdonation, that is, after transfusion of cellular blood products, whereas at the Frankfurt Institute all donations are screened before releasing any blood product. In this study, we evaluated the infectivity of B19-positive blood products in relation to the virus concentration in the transfused blood component. STUDY DESIGN AND METHODS: Recipients were classified into two groups (A, transfused with blood products with B19 virus load less than 10(5) IU/mL; and B, transfused with blood products with B19 virus load greater than 10(5) IU/mL). Phylogenetic analyses were done for B19 DNA-positive donor and recipient pairs in the variant VP-1u genome region. All samples were investigated for immunoglobulin (Ig)M and IgG B19 antibodies. RESULTS: B19 DNA was detected in 9 of 18 recipients of red blood cells (RBCs) from Group B, whereas none of the 16 recipients of RBCs from Group A were positive for B19 DNA (p=0.016). Phylogenetic analysis demonstrated identical genomic sequences between the donors and recipients. Because recipient B19 DNA and antibody results were not available before transfusion, we interpret our overall data to indicate equivocal evidence of B19 transmission by RBC transfusion. CONCLUSION: B19 transmission by cellular blood products correlates with the virus concentration and the concentration of neutralizing antibodies. Thus, blood donor screening for B19 by minipool NAT should be done to supply at-risk patients (e.g., immunosuppressed patients) with B19-negative blood components.

First transmission of human immunodeficiency virus Type 1 by a cellular blood product after mandatory nucleic acid screening in Germany.

BACKGROUND: In February 2007, a 63-year-old man underwent surgery. Retrospective testing with nucleic acid testing (NAT) showed that the patient was human immunodeficiency virus Type 1 (HIV-1) positive 10 days after transfusion. The transfusion-transmitted infection had been identified by a donor-related lookback started in April 2007 after anti-HIV seroconversion. METHODS: Sequence analysis was performed in the gag-pol region as well as in the V3 loop env region. Archived plasma from the transmitting donation was investigated for the individual-donation NAT with the Roche COBAS AmpliPrep/COBAS TaqMan HIV-1 test (Roche CAP/CTM HIV-1 test) and for HIV antigen/antibody combination testing (Abbott Architect). Additional testing was done on the donor's follow-up sample and on the recipient's sample. RESULTS: The Roche CAP/CTM HIV-1 test failed to detect viral RNA by minipool NAT in the index donation (April 2007) as well as in the donation that caused the infection (January 2007). Phylogenetic analysis showed a very high genetic similarity among viral sequences from both donor and recipient, proving the HIV-1 transmission by sequence data. CONCLUSION: This case represents the first documented HIV-1 transmission by transfusion of red blood cells after mandatory introduction of HIV-1 NAT for blood screening in Germany. Low viral load and mismatches in the primer/probe region might explain the detection failure of the NAT screening assay. A certain risk remains that new virus variants contain mutations at positions critical for amplification or detection of viral genomes. An option to reduce the risk of a detection failure by NAT is the simultaneous use of several conserved regions as amplification targets.

Blood donor screening for parvovirus B19 in Germany and Austria.

BACKGROUND: Although the main transmission pathway of parvovirus B19 (B19) is typically via the respiratory route, several transfusion-transmitted infections have been reported. To increase blood safety, all blood donations to our blood donor service have been screened by a B19 minipool real-time nucleic acid testing (NAT) since April 2000. Additional customers have been screened since the summer of 2003. STUDY DESIGN AND METHODS: In total, 2.8 million donations from Germany and Austria were screened for B19 by real-time minipool NAT. A subgroup of 50 B19 DNA-positive donors was screened for B19 immunoglobulin G (IgG) and IgM antibodies and B19 DNA over a 6-month period. Results were compared to those of 100 B19 DNA-negative donors. RESULTS: Data accumulated over the past 6 years indicate a high incidence period from May 2004 to January 2006. In total, the incidence was 12.7 and 261.5 per 100,000 donations with high virus loads equal to or above 10(5) and below 10(5) IU per mL, respectively. Median virus concentration in the case group was 4.85 x 10(7) IU per mL at Time Point T0 and was reduced to 4 x 10(2) IU per mL at the time of the next donation (3 months later). Neutralizing antibodies (VP2) were detected in all donations if virus load was reduced to less than 10(5) IU per mL. CONCLUSION: The release of B19 DNA-positive blood products with a concentration of less than 105 IU per mL is thought to be safe due to the high level of neutralizing VP2 antibodies and is currently examined in a donor recipient infectivity study. In contrast, blood products with a high B19 DNA concentration (> or =10(5) IU/mL), some of which did not contain neutralizing antibodies, were discarded to protect at risk individuals.

Blood screening for influenza.

Influenza viruses, including highly pathogenic avian influenza virus (H5N1), could threaten blood safety. We analyzed 10,272 blood donor samples with a minipool nucleic acid amplication technique. Analytical sensitivity of the method was 804 geq/mL and 444 geq/mL for generic influenza primers and influenza (H5N1) subtype-specific primers. This study demonstrates that such screening for influenza viruses is feasible.

Hepatitis B virus genotype G monoinfection and its transmission by blood components.

An acute hepatitis B virus (HBV) infection was diagnosed in a regular apheresis (plasma/platelet) donor by the hepatitis B surface antigen (HBsAg) assay and minipool nucleic acid amplification technology (NAT). The acute infection was confirmed by detection of anti-HBc (IgM) and anti-HBs 2 weeks later. The donor showed no clinical symptoms and had normal alanine aminotransferase levels. He had a history of weekly apheresis plasma or platelet donations. Archived material from the donor and the respective recipients was investigated by sensitive HBV NATs as part of a look-back procedure. HBV DNA was detectable in previous donations as well as in two recipients transfused with platelet concentrates. The rare HBV genotype G was identified in all HBV-DNA-positive samples. Strong evidence of genotype G monoinfection was obtained by clonal sequencing, HBV genotype line probe assay, genotype-specific NATs, and restriction pattern analysis. In contrast to previously described genotype G infections, which all appeared as coinfections with genotype A, neither the hepatitis B e antigen (HBeAg) nor anti-HBe was detectable in any of the samples. This shows that HBeAg is dispensable for viral replication. The delay in detecting HBsAg in both the donor and recipient samples may be explained by either decreased genotype G-specific synthesis of incomplete viral forms in early HBV infection or the lower sensitivity to genotype G of the current HBsAg assays. In conclusion, this reported case of an HBV infection was caused exclusively by genotype G.