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Background and objectives Human hepatitis E virus (HEV) is prevalent worldwide. Iatrogenic HEV has recently been identified based on the reports of transfusion-transmitted cases. The detection rate of HEV-RNA and seroprevalence of HEV-IgG/IgM have been regionally evaluated in Japan, and donor plasma collected in Hokkaido is currently screened by nucleic acid amplification testing. However, the detection rate of HEV-RNA in blood donors in Japan outside of Hokkaido has not been reported. Materials and Methods A total of 620 140 qualified donor plasma samples from Japanese regions excluding Hokkaido were tested for HEV-RNA (pools of 50 or 500) between 2004 and 2014. HEV-RNA-positive plasma bags were identified, and the HEV viral load, genotype and anti-HEV immunoglobulin (Ig)G/IgM were evaluated. Results The detection rate of HEV-RNA (pools of 50) was 1/15 075 and higher in eastern than in western Japan. All 36 HEV-RNA-positive samples were genotype 3 with viral load ranging from

Background and Objectives Our previous report showed that parvovirus B19 genotype 1 in different solutions derived from plasma preparations showed different heat-sensitivity patterns during liquid-heating. In this study, we similarly examined B19 genotype 2. Materials and Methods Two plasma samples one containing B19 genotype 1 and the other genotype 2 DNA were used. Four process samples collected immediately before the heat treatment step in the manufacture of albumin, immunoglobulin, haptoglobin and antithrombin preparations were spiked with B19 and subsequently treated at 60°C for 10 h. A low pH immunoglobulin solution was also spiked with B19 and treated at room temperature for 14 days. Infectivity was then measured. Results B19 genotype 2, similar to genotype 1, showed three patterns of inactivation: (i) a rapid inactivation in the albumin and immunoglobulin preparations, (ii) a slow inactivation in the haptoglobin preparation and (iii) only limited inactivation in the antithrombin preparation. Its sensitivity in the low pH immunoglobulin solutions also resembled that of genotype 1. Conclusion Both genotypes 1 and 2 of B19 varied in sensitivity to liquid-heating and low pH among different plasma preparations.

Background and Objective To investigate the physico-chemical properties of hepatitis E virus (HEV) with regard to inactivation/removal, we have studied four isolates with respect to sensitivity to heat during liquid/dry-heating as well as removal by nanofiltration. Materials and Methods Hepatitis E virus in an albumin solution or phosphate-buffered saline (PBS) was liquid-heated at 60°C for a preset time. HEV in a freeze-dried fibrinogen containing stabilizers was also dry-heated at 60 or 80°C for a preset time. In addition, to clarify the removal of HEV, the purified virus in PBS was filtered using several types of virus-removal filter (nanofilters) that have different pore sizes. HEV infectivity or genome equivalents before and after the treatments were assayed by a semiquantitative cell-based infectivity assay or quantitative polymerase chain reaction assay, respectively. Results Hepatitis E virus isolates in albumin solutions were inactivated slowly at 60°C for 5 h and the resultant log reduction factor (LRF) was from 1·0 to ≥ 2·2, whereas the virus in PBS was inactivated quickly to below the detection limit and the LRF was ≥ 2·4 to ≥ 3·7. The virus in a freeze dried fibrinogen containing trisodium citrate dihydrate and l-arginine hydrochloride as stabilizers was inactivated slowly and the LRF was 2·0 and 3·0, respectively, of the 72 h at 60°C, but inactivated to below the detection limit within 24 h at 80°C with an LRF of ≥ 4·0. The virus in PBS was also confirmed as to be approximately 35 nm in diameter by nanofiltration. These results are useful for evaluating viral safety against HEV contamination in blood products. Conclusion The sensitivity of HEV to heat was shown to vary greatly depending on the heating conditions. On the other hand, the HEV particles were completely removed using 20-nm nanofilters. However, each inactivation/removal step should be carefully evaluated with respect to the HEV inactivation/removal capacity, which may be influenced by processing conditions such as the stabilizers used for blood products.

Background and objectives To date there has been no published report on a systematic evaluation of the heat sensitivity of human parvovirus B19 (B19) and the related safety of the plasma-derived fractionated products. In this study, we examined the heat sensitivity of B19 by using the infectivity assay with cultured cells. Materials and methods The heat sensitivity of B19 was examined by measuring the reduction in viral infectivity titres after heating liquid containing B19 at 60 degrees C. Viral infectivity was assayed by detection of viral antigens or viral mRNA in infected cells. As a control, canine parvovirus (CPV) was also heat-treated. Results B19 displayed quite different inactivation kinetics to CPV when both were heated in liquid at 60 degrees C. In sharp contrast to the latter, B19 was rapidly inactivated within 1 h when the virus was suspended in 5% or 25% human serum albumin solution, phosphate-buffered saline, or complete medium. However, B19 appeared to be resistant to heat inactivation in liquid containing 60% sucrose. Conclusions The heat sensitivity of B19 in liquid was clearly different from that of CPV. Significantly, the efficiency to inactivate B19 and reduce its infectivity following heating in liquid was mainly affected by the composition of the solutions used for virus suspension.

Our previous report showed that parvovirus B19 genotype 1 in different solutions derived from plasma preparations showed different heat-sensitivity patterns during liquid-heating. In this study, we similarly examined B19 genotype 2.Two plasma samples one containing B19 genotype 1 and the other genotype 2 DNA were used. Four process samples collected immediately before the heat treatment step in the manufacture of albumin, immunoglobulin, haptoglobin and antithrombin preparations were spiked with B19 and subsequently treated at 60°C for 10 h. A low pH immunoglobulin solution was also spiked with B19 and treated at room temperature for 14 days. Infectivity was then measured.B19 genotype 2, similar to genotype 1, showed three patterns of inactivation: (i) a rapid inactivation in the albumin and immunoglobulin preparations, (ii) a slow inactivation in the haptoglobin preparation and (iii) only limited inactivation in the antithrombin preparation. Its sensitivity in the low pH immunoglobulin solutions also resembled that of genotype 1.Both genotypes 1 and 2 of B19 varied in sensitivity to liquid-heating and low pH among different plasma preparations.

Background and Objectives Previously, we reported that although human parvovirus B19 in albumin and intravenous immunoglobulin preparations was rapidly inactivated during liquid heating, in contrast to other parvoviruses such as canine parvovirus, sensitivity to heat was highly dependent on the composition of the solution. In this study, we aimed to further elucidate the sensitivity to heat of B19 in haptoglobin and antithrombin (previously named antithrombin III) preparations during liquid heating. Materials and Methods Two different solutions collected immediately before heat treatment of haptoglobin and antithrombin preparations were spiked with B19 and subsequently treated at 60 °C for 10 h. B19 DNA-positive, anti-B19 IgG/IgM-negative plasma was used as a source of B19. The residual infectivity in each sample was measured using a B19 cell-based infectivity assay with an mRNA polymerase chain reaction. Results B19 in different plasma preparations showed different heat-sensitivity patterns during liquid heating: (i) slow inactivation in haptoglobin preparations, and (ii) only limited inactivation in antithrombin preparations. The kinetics of inactivation was greatly different from that in our previous studies in which the virus was shown to be rapidly inactivated in albumin and intravenous immunoglobulin preparations. Conclusion B19 has unique properties in terms of heat sensitivity, depending on the composition of the solution during liquid heating. This finding may indicate the need for caution when interpreting the sensitivity of B19 to heat.

Background and objectives Various measures to inactivate/remove viruses have been implemented for manufacturing plasma-derived products. Here, we examined the heat inactivation ability of an agent of the severe acute respiratory syndrome (SARS), SARS coronavirus (CoV). Materials and methods The Frankfurt-1 strain of SARS-CoV was incorporated in manufacturing processes of several products by using samples collected immediately before liquid heat treatment at 60 degrees C. Results SARS-CoV was easily inactivated by this treatment for 60 min in all in-process samples. However, the different composition of the tested samples affected the heat sensitivity of the virus strain: the infectivity of the virus in Antithrombin III preparation still remained after heating for 30 min at 60 degrees C. Conclusion If by rare chance SARS-CoV contaminates source plasma, there should be no or only minor risk of this virus infection, due to sufficient inactivation by the 60 degrees C 10 h liquid heating step, although we must pay attention to the composition used for blood product preparation.