Prospects for improved bluetongue vaccines

Key Points Bluetongue, one of the most devastating and widespread animal diseases, is caused by a virus that is transmitted between animals by a blood-feeding insect vector. It has been recognized as a viral disease of livestock for more than 100 years and has since spread to many countries around the world. There are 24 serotypes of bluetongue virus, 7 of which have been present in Europe during the past 10 years. An important control measure is vaccination. The current vaccines consist of modified live viruses and purified viral proteins, which have severe drawbacks, such as the requirement for multiple vaccinations and the possibility of reassortment. A promising vaccine under development is based on virus-like particles that are made using baculovirus expression systems. These vaccines show high antigenicity and may require fewer rounds of vaccination. Improvements in molecular techniques have allowed the production of genetics-based modified live virus vaccines that will make vaccine strains safer and provide tools to track the possible spread of vaccine strains after vaccination. Bluetongue virus is a substantial health risk to sheep and other ruminants. Livestock can be protected by vaccination, but as described in this Review, current vaccines can have severe drawbacks. New molecular techniques will provide safer and more effective vaccines and allow for better surveillance of the spread of vaccine strains. Bluetongue has been recognized as a viral disease of livestock for more than 100 years. Repeated incursions of Bluetongue into Europe since 1998 have been particularly devastating for highly sensitive European fine-wool sheep breeds, and have resulted in a resurgence of interest in vaccine manufacture. Fortunately, the virus and its serology are well understood and vaccination prevents the disease. However, current vaccines are not without their problems, and many new approaches are being tested to improve the safety and breadth of protection afforded. This Review describes the leading technologies for improved bluetongue vaccines and looks ahead to how advances in other viral vaccines might be applied to this disease.