Mitigation of the Risk of Importing Akabane and Exotic Bluetongue Virus in Ruminant-Sourced Sera

Akabane virus is an arbovirus of the Bunyaviridae family that is endemic in certain tropical and subtropical regions, including parts of Asia, Africa, the Middle East, and Australia. Since Australian-sourced fetal bovine serum (FBS) is a preferred reagent for use in regulated cell culture applications (including but not limited to manufacturing processes for human and veterinary biologics), the importation of FBS from Australia represents a risk to United States livestock in the form of possible introduction of Akabane virus. This risk is currently mitigated, per United States Department of Agriculture (USDA) mandate, through importation testing and/or barrier treatment of the incoming serum by gamma irradiation at ≥30 kGy. Gamma irradiation, while effective for inactivating any infectious Akabane virus that might be present in the serum pools or finished serum product, is not a practical solution for all types of imported serum products. The testing that is currently required by the USDA for Akabane virus and exotic bluetongue viruses involves the use of virus-naïve sheep, is not characterized (validated) for limit of detection, and is not high-throughput, resulting in delays in satisfying import requirements for importation of serum. This opinion paper discusses these topics in detail and proposes alternative testing methodologies that should overcome the various limitations of the current testing protocol. Following development and validation of the proposed methods for limit of detection at the ultimate USDA testing site, decisions regarding the suitability of these methods to replace the current sheep antibody production assay may be made by the USDA.