Vaccines for prevention of bluetongue and epizootic hemorrhagic disease in livestock: A North American perspective

Authors: McVey, David; MACLACHLAN, N - University Of California

Submitted to: Vector-Borne and Zoonotic Diseases
Publication Type: Review Article
Publication Acceptance Date: 6/1/2015
Publication Date: 6/1/2015
Citation: Mcvey, D.S., Maclachlan, N.J. 2015. Vaccines for prevention of bluetongue and epizootic hemorrhagic disease in livestock: A North American perspective. Vector-Borne and Zoonotic Diseases. 15(6):385-396.

Interpretive Summary: 1. Use of attenuated (MLV) vaccines be avoided if possible, although these are the onlyvaccines available currently in the U.S. and their use to protect against serotypes 10, 11 and 17 may need to continue for the near future in sheep. These vaccines do provide good protection from clinical disease with homologous serotype infections. There are no currently licensed vaccines available for EHDV in the U.S. 2. If there is a need to rapidly develop a vaccine to meet an emerging crisis associated with an especially virulent orbivirus of a single serotype, development of an inactivated virus vaccine in a conventional adjuvanted formulation will be required. With two doses of vaccine, inactivated vaccines can provide substantial immunity to the epizootic serotype. This strategy is similar to that used in the 2006-2008 BTV-8 outbreak in northern Europe which provided vaccine to the field by 2008. There is a need to explore and develop regulatory mechanisms to deploy such vaccines in an emergency situation. 3. The gaps in our scientific knowledge and available countermeasures to control a disease outbreak have significant gaps and require improvements that can only be achieved through a coordinated research agenda to achieve a more optimal vaccine profile.

Technical Abstract: Bluetongue (BT) and epizootic hemorrhagic disease (EHD) are non-contagious, insect transmitted diseases of domestic and wild ruminants caused by related but distinct viruses. Both BT (BTV) and EHD (EHDV) viruses cause hemorrhagic fevers in susceptible ruminants; however BT is principally a disease of domestic livestock whereas EHD is principally a disease of certain species of wild, non-African ungulates, notably White-tailed deer. The live-attenuated (modified live virus [MLV]) vaccines available in the United States (U.S.) for use in small ruminant livestock do provide good protection against clinical disease following infection with the homologous virus serotype. Although there is increasing justification that use of MLV vaccines should be avoided if possible, these are the only vaccines currently available in the U.S. Specifically, MLVs are used in California to protect sheep against infection with BTV serotypes 10, 11 and 17, and a MLV to BTV serotype 10 is licensed for use in sheep throughout the U.S. These MLV vaccines may need to continue to be used in the immediate future for protective immunization of sheep and goats against BT. There are no currently licensed vaccines available for EHD in the U.S. If there is a need to rapidly develop a vaccine to meet an emerging crisis associated with either BTV or EHDV infections, development of an inactivated virus vaccine in a conventional adjuvanted formulation will likely be required. With two doses of vaccine (and in some instances just one dose), inactivated vaccines can provide substantial immunity to the epizootic serotype of either BTV or EHDV. This strategy is similar to that used in the 2006-2008 BTV serotype 8 outbreaks in northern Europe which provided vaccine to the field within 2 years of the initial incursion (by 2008). There are significant gaps in our scientific knowledge and available countermeasures to control an outbreak of orbivirus-induced disease, whether BT or EHD. It is concluded that a coordinated national research strategy to achieve a more optimal vaccine profile should be developed.