When you combine the fact that asymptomatic individuals can have high levels of circulating virus with the fact that B19 is a non-enveloped DNA virus and as such is highly resistance to heat, solvent and detergent treatments, you begin to see the challenges facing the blood banking industry [39]. Solvent detergent

treatment, which is highly effective for inactivating enveloped viruses like HIV, HBV and HCV, does not inactive non-enveloped viruses like B19 and HAV. As a result of this, the industry has had to turn to using more complicated and expensive dry-heat treatment and nano-filtration methods to reduce or eliminate the level of non-enveloped viruses. In most countries, blood is not routinely screened for the presence of B19. Determining whether to screen blood and/or blood products for B19 and at what level, if any, B19 is considered a find more minimal or Compound Library mouse low risk for transmission is being actively addressed. As B19 cannot easily replicate in conventional cell or tissue culture methods, nucleic acid amplification testing (NAAT) has been developed and is the recommended method used to screen blood and blood products for the presence of B19 DNA. The Food and Drug Administration does not currently mandate

screening the blood supply for B19, but is proposing that manufactured pools contain plasma B19 DNA levels consistently below 104 geq mL−1 [36]. Similarly, the Health Council for the Netherlands (2002/07; ISBN) considers 104 geq mL−1 the maximum permissible limit. The Health Council for the Netherlands has also recommended that a high-risk group approach be adopted for cellular medchemexpress blood products containing B19 DNA. In Europe, although there is no official guideline published for plasma pools, and screening of blood donations for B19 DNA is not routine, many manufacturers now voluntarily perform B19 polymerase chain reaction on plasma pools. The basis for the current recommended viral load cutoff came from observations of healthy volunteers. The findings of these studies suggest that

acute B19 infection can occur from administration of blood components containing ≥107 geq mL−1 of B19 DNA. In contrast, patients receiving <104 geq mL−1 have not shown evidence of virus transmission [36,40]. A recent study linking donors and recipients was undertaken to assess the risk of transmission from B19 DNA-positive units containing <106 IU mL−1 into B19 susceptible recipients (B19-specific IgG negative). In this study, 105 B19 DNA-positive donations resulted in the transfusion of 112 B19-positive components into 107 recipients. None of the 24 susceptible cases resulted in a B19 infection [41]. Other investigators found that transmission did not occur in components containing <106 IU mL−1, transmission.