Porcine reproductive and respiratory syndrome virus (PRRSV) is a viral disease of swine characterized by reproductive impairment or failure in breeding animals, and respiratory disease in pigs of any age. PRRS is an economically significant disease affecting swine, costing the pork industry more than $664 million annually. Restriction fragment length polymorphism (RFLP) analysis is used to asses genomic variation within the highly variable type 2 PRRSV ORF5. Phylogenetic relationships between PRRSV strains can then be generated at the individual farm level to monitor local changes within a herd. The ADDL offers rapid sequencing of the ORF5 region, with phylogenetic analysis upon request.
The ADDL performed 7,865 PRRS RT-qPCRs for our clients in 2019. More than 100 PRRSV-positive samples were submitted for ORF5 sequencing and analysis. Client reports include the sequence-determined RFLP pattern and a summary of how closely related a PRRSV may be to commercial vaccines or if the virus is considered a wild-type strain.
Several years of ORF5 sequence data has been collected from Ohio swine herds, with the distribution of RFLP patterns sequenced in 2019 provided in the graph below. In 2019, the two most common RFLPs were 2-5-2 and 1-7-4.
PRRSV ORF5 sequencing costs $95. Customer dendrograms can be created upon request.
Melanie Prarat, MS, ADDL Virology Section Researcher