An RNA virus, designated hepatitis G virus (HGV), was identified from the plasma of a patient with chronic hepatitis. Extension from an immunoreactive complementary DNA clone yielded the entire genome (9392 nucleotides) encoding a polyprotein of 2873 amino acids. The virus is closely related to GB virus C (GBV-C) and distantly related to hepatitis C virus, GBV-A, and GBV-B. HGV was associated with acute and chronic hepatitis. Persistent viremia was detected for up to 9 years in patients with hepatitis. The virus is transfusion-transmissible. It has a global distribution and is present within the volunteer blood donor population in the United States.

First, the residual risk in Australian donors is small in comparison with other transfusion complications and comparable to or lower than the risk in US and European nonremunerated donors. Second, mathematical risk modeling has sufficient precision to be used as a predictive tool for risk-benefit assessments of novel screening procedures. Finally, in relation to the case for implementing HBV NAT and/or anti-HBc in Australia, we conclude that at present, there is inadequate information about our donor population to perform an evidence-based risk-benefit analysis.

Background and Objectives In 2005, the Australian Red Cross Blood Service implemented a malaria antibody testing based strategy for donors with a history of travel ⁄ residence in a malaria endemic country or a past history of malaria. This report assesses the safety and efficacy of the strategy since inception. Materials andMethods Eligible blood donors were tested using the Newmarket malarial antibody EIA at least 4 months after their last potential exposure. Where EIA non-reactive their quarantined red cells were considered for transfusion and they were re-instated for cellular component manufacture at their next donation. The efficiency and safety of this strategy were evaluated based on the additional number of components recovered for transfusion and the observed incidence of transfusion transmitted malaria (TTM) respectively.Results Of the repeat reactive donors, 2696 (> 99AE99%) were PCR negative whilst one was PCR positive with very low level parasitaemia. The average number of RBCs and platelets recovered per annum was 64 967 and 7398 representing 7AE9 and 5AE5% respectively of their annual production. No new TTM cases were recorded and the observed TTM rate of zero was consistent with the upper 95% CI for the pretesting TTM incidence of 0AE9 per million donations. ConclusionThe study findings support the efficacy and safety of a targeted screening strategy combining a sensitive antibody screening test with a 4-month cellular component restriction period for donors with a declared malarial risk. The TTM risk in Australia remains low and did not measurably change after implementing the testing strategy.Key words: blood donor, malaria, screening, transfusion. IntroductionMalaria is a protozoan parasitic infection of humans resulting from infection by one or more of the five species of the genus Plasmodium (P. falciparum, P. vivax, P. ovale, P. malariae and P. knowlesi) [1,2]. Transfusion transmitted malaria (TTM), although rare, continues to pose a risk to blood services worldwide with recent transmissions invariably resulting from 'semi-immune' donors who may carry undetectable levels of parasites without overt symptoms [3][4][5][6][7][8][9]. Of the five Plasmodium species, P. falciparum is the most serious transfusion risk since it is fatal in approximately 10% of patients infected in this way [10]. Although malaria is not endemic in Australia, there are between 500 and 900 cases of imported malaria annually constituting an ongoing TTM risk [11]. The last documented Australian TTM case, a fatality associated with P. falciparum, occurred in 1991 [12], this being the first reported transfusion Due to the lack of a suitable high throughput laboratory test, screening for malaria in Australian blood donors prior to July 2005 relied on collecting a comprehensive medical and travel history as part of the donor assessment process and exclusion of cellular blood components from those with potential risk exposure to Plasmodiae. At that time, the Australian Red Cross Blood Service (ARCBS) Guidelines for the select...

Background and Objectives Australia introduced bacterial contamination screening (BCS) for platelet components in April 2008. This study presents analysis performed to assess the efficacy of testing.Materials and Methods Seven-day aerobic and anaerobic culture is performed using the BacT/ALERT 3D system. Following an initial machine positive (IMP) flag, all associated components are recalled, and/or clinicians treating already transfused patients are notified. IMPs are categorized as 'machine false positive', 'confirmed positive' or 'indeterminate' depending on culture results of initial and repeat samples.Results Between 2010 and 2012, 1Á1% of platelet donations tested IMP; since 2013, this rate has fallen to 0Á6% through improved instrument management, reducing false-positive IMPs but maintaining sensitivity for cultures yielding bacterial growth. On average, 66% of confirmed positive and indeterminate platelet units had been transfused at the time of detection. The majority (95%) of these grew Propionibacterium sp., a slow-growing organism that rarely causes sepsis in the transfusion setting. The incidence of reported transfuion-transmitted bacterial infection (TTBI) has fallen since the introduction of BCS, with a 4Á2-fold [0Á5, 28Á2] lower rate from platelets.Conclusion BCS has been successful in detecting platelet units containing pathogenic bacteria. The incidence of TTBI from platelets has fallen since the introduction of BCS, but the risk has not been eliminated due to rare false-negative results. In the absence of a pathogen inactivation system for red blood cells, BCS provides 'surrogate' testing of red blood cells from which platelets have been manufactured.

Both the prevalence and the incidence of TTIs in Australian blood donors remained low, with a steady or declining trend for most infections except active syphilis. The lower prevalence of TTIs in blood donors compared with the general population reflects the effectiveness of donor education and donor selection measures in Australia.