Rapid, In-Field Method for Genomic-Based Identification of BVDV

BVDV is a highly contagious disease that affects ruminant livestock. The virus is spread among cattle, is found in most parts of the world and is considered a high priority by the USDA. BVDV affects nutrition, milk production, respiratory and reproduction functions of cattle. BVD can suppress the immune system thus increasing susceptibility to pneumonia, diarrhea (scours), and reproductive failure (abortions, mummifications, congenital defects). Infected pregnant cows may abort spontaneously or give birth prematurely, while calves that are born are often persistent carriers that are infected for life and a constant threat to infect additional cattle. Persistently infected cattle (PI) animals shed virus throughout their lives and are the primary vector for virus introduction to native herds. The disease causes significant economic loss to the beef and dairy industries. PI prevalence in the US cattle population has been reported between 0.13% and 2.0%. About 4% of US beef herds are estimated to have at least one PI animal. The same source estimates a loss of $47 per head of cattle entering a feed yard. The US industry is comprised of 96.8 M head of cattle and was estimated by the USDA to be worth $74.1B in 2007. From these figures, the PI population ranges from 125,000 to nearly 2M in the US. The main practice to minimize spread from PI animals includes quarantine of infected animals. Vaccination can be used to manage BVD, but cannot reliably prevent disease if PI cattle are present. Vaccination can decrease disease and reduces risk of viral shedding cattle. No vaccine protects fetuses from all strains of BVD but they can reduce transmission risk and post infection disease impact if they are appropriately administered. Uncertainties about vaccines remain and include a lack of understanding about the length of immunity and whether vaccines prevent transplacental transmission. The most common BVDV detection method for identifying PI animals has been immunohistochemical staining of skin biopsies for viral antigen, usually from an ear-notch sample. Other PI identification methods include virus isolation from serum, blood, and other tissues (VI); antigen-capture ELISAs (AC-ELISA), plasma or phosphate-buffered saline incubated skin samples; and reverse-transcriptase polymerase chain reaction (RT-PCR) assays.10,30 In general, these tests must be conducted in a laboratory. The best test costs average $8 per cattle head but require 3 to 4 day turnaround. New methods using RT-PCR cost about $7 per head and improve response to two days. The costs cited are only for test components and reagents, not costs for sample transport and performance of lab work. INT believes their Palladium system can identify the presence of BVDV and offers advantages over current methods. The INT platform provides in-field results in minutes and requires virtually no training. Because results are read on site, workload in lab facilities is reduced and an active isolation program can begin immediately ? something that does not occur now due to test limitations INT will design and build a rapid, simple-to-use test to identify strains of BVD.