Publications by authors named "G C Darsie"

The threat of using biological material for ago-bioterrorist ends has risen in recent years, which means that research and diagnostic laboratories, biological agent banks and other institutions authorised to carry out scientific activities have had to implement biosafety and biosecurity measures to counter the threat, while carrying out activities to help prevent and monitor the accidental or intentional introduction of exotic animal diseases. This article briefly sets outthe basic components of biosafety and biosecurity, as well as recommendations on organisational strategies to consider in laboratories that support agro-bioterrorist surveillance and prevention programs.

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Since the beginning of organized campaigns in the 1960s, vaccination has been a major component of national FMD control and eradication programmes in South America. Aqueous vaccines were used in the 1960s and 1970s, and the introduction of oil vaccines in the mid 1980s helped to decrease endemism. Bi- and trivalent FMD vaccine production increased from 266 thousand doses in 1967 to 580 million doses in 2002.

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Four groups of ten nine-month-old Nelore heifers were used for this study. Each group received one of four foot-and-mouth disease (FMD) trivalent vaccines for the duration of the experiment. The four vaccine formulations (Normal, 2X, 4X and 8X) differed in 140S content to determine the serological reactivities to FMD virus (FMDV) nonstructural proteins 2C, 3ABC and 3D.

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Panels of monoclonal antibodies (mAbs) produced against foot-and-mouth disease (FMD) virus types O, A and C were selected for cell culture neutralization titre (NT), mouse protection index (MPI), trypsin sensitivity (TS) and avidity to different epitopes. The selected sets were used to assay the antigen concentration and the fit between FMDV vaccine and challenge strains. It was observed that FMD vaccines protect more than 75% of vaccinated cattle when manufactured with antigens characterized by (1) a high degree of fit with the potency control virus, and (2) mean ELISA 50% titres (T50) > 28 for O, > 18 for A and > 75 for C types, respectively, using the corresponding mAb set.

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