This contamination was initially identified during manufacture of Hyate:C by observation of cytopathic effects in cultured mammalian cells and PPV DNA was subsequently identified using polymerase chain reaction technology. Infection with human parvovirus B19 is very common in the general population and does not cause significant illness. Furthermore, it is well-documented that human parvovirus can be transmitted by modern plasma-derived AG14699 concentrates subjected to virucidal treatment, such as heat-treatment

and solvent/detergent treatment. The interruption of manufacture of Hyate:C may therefore seem in retrospect to have been a somewhat drastic step to take. However, this came at a time of heightened concern about zoonoses, as it was in this same year that vCJD was first reported in humans, and acknowledged to be the result of transmission of prions from cattle infected with bovine spongiform encephalopathy

MK-8669 mouse (BSE). A subsequent retrospective study of 81 patients, who had received Hyate:C showed no serological evidence of infection with porcine parvovirus (PPV), encephalomyocarditis virus (EMCV) or porcine respiratory and reproductive syndrome virus (PRRSV) [20]. There was also no evidence of infection with these pathogens in 125 control subjects, who included workers in the pig abattoir and personnel involved in the manufacture of Hyate: C at the Wrexham plant, as well as recipients of porcine heparin or insulin. A separate study in the United States of America identified PPV DNA in 21 of 22 different batches of Hyate:C using nested PCR testing, although none of 98 Hyate:C recipients tested positive for PPV IgG antibodies [21]. Another study reported the presence of porcine endogenous click here retrovirus (PERV) particles in all of six batches of Hyate:C screened, although infectious virus was not detected [22]. PERV particles were shown to be a common contaminant of Hyate:C products, but the risk of actual transmission of PERV infection was deemed to be very low [23]. A change in the manufacturing process to incorporate a virucidal step, such as heat-treatment would

have necessitated a formal clinical trial to satisfy the requirements of the regulatory agencies, which would have been a huge undertaking. The company decided instead to introduce serological screening of all porcine plasma for antibodies to PPV and only select seronegative plasma for fractionation. As PPV infection is very common amongst swine, this resulted in a significant reduction in plasma cleared for fractionation at the plant and thus the total number of vials produced. Manufacture of Hyate:C eventually ceased at the Wrexham plant in 2004, and the last vial was supplied for clinical use the following year. It is probably fair to say that the challenge posed by the introduction at around the same time of recombinant activated factor VII (NovoSeven, NovoNordisk), also played a significant part in the demise of Hyate:C.