The U.S. Department of Agriculture (USDA) has issued the Veterinary Biological License for Viralign 6, the first combination modified-live virus (MLV) vaccine to provide targeted protection against bovine viral diarrhea (BVD) virus 1b — the most predominant BVD virus strain in the United States.1 Marketed by Elanco, Viralign 6 also provides protection against BVD viral strains 1a and 2, bovine respiratory syncytial virus (BRSV), infectious bovine rhinotracheitis (IBR) virus and parainfluenza3 (PI3) virus.
“Until now, veterinarians and producers have relied on combination vaccines with BVD 1a and 2 to cross protect against what is now the most predominant strain: 1b,” says Carl Guthrie, D.V.M. and director of Elanco beef technical services. “We are pleased that Elanco’s debut cattle vaccine is the very first USDA-approved MLV vaccine to include antigens for all three major BVD viruses, including 1b.”
This first-of-its-kind vaccine enables low-volume, subcutaneous administration in cattle 5 months of age or older.
“Even though producers have vaccinated for the BVD virus for years, research shows its incidence has not gone down,1 and 1b has replaced 1a as the most predominant BVD strain,” says Guthrie. “The good news is that ongoing vaccination programs appear to have decreased the predominance of 1a in the United States. But, it also suggests current modified-live 1a vaccines may not adequately protect calves from 1b infections. Since BVD is the most costly viral disease in cattle,2 Viralign 6 is an important herd-health tool that will help combat all three major BVD strains.”
BVD is evolving and highly contagious
The BVD virus is an RNA virus, which means it is more susceptible to mutation. That’s why researchers monitor BVD viral strains to identify changes in predominance. In fact, a USDA Agriculture Research Service analysis of diagnostic samples shows there has been a shift in predominance of BVD viral strains in the United States. In 1988, subtype 1a was predominant at 51 percent. Twenty years later, 1a ranked third at 18 percent, while subtype 1b had increased in predominance from 41 percent to 61 percent.1 At the same time 1a was decreasing, the overall incidence of BVD virus did not decline.1
“One of the primary sources of the BVD virus is exposure to persistently infected (PI) animals — cattle that are few in number, but shed large amounts of the virus throughout their lives,” says Brad Williams, D.V.M., MBA and Elanco senior technical consultant. “Comprehensive research involving 21,743 head shows that 78 percent of PI cattle were infected with 1b."3