#16-205

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Date Full Report Received

Date Abstract Report Received

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Porcine Reproductive and Respiratory Syndrome Virus continues to be a leading cause of disease and decreased production in the swine industry. Detection of virus is not sufficient to determine if this is modified live vaccine, continuing low level infection, or introduction of new strains of the virus that have entered a herd or facility. Therefore, this project looked to combine detection and genotyping using a newly available sequencing method. This project was able to successfully detect and genotype virus from experimentally and naturally infected pigs using serum. In experimental infections where the virus used is known, we were able to correctly identify the inoculated virus each time and were able to detect mixed infections when two samples were mixed. In addition, we have developed a method of data analysis that allows us to identify PRRS virus sequences from among the millions of sequences obtained and to classify the virus within 90 seconds. We are refining this method so that it is automated and better classifies viruses that do not match those sequences found in published databases. This sequencing technology has the ability to selectively sequence and reject unwanted genetic material. Attempts to use this approach were of limited success. Due to the high speed of sequencing reactions and relatively short read lengths, the enrichment was not sufficient to warrant the approach. Alternate enrichment approaches are funded and underway with the intent of making this as fast or faster than current PCR results and at a similar cost. In addition, to increase throughput and efficiency while providing value-added results, we are sequencing ORF5 amplicons at a materials cost similar to that of traditional Sanger sequencing but with the added benefit of being able to detect multiple viruses or modified live vaccine and wildtype virus in the same sample. If you would like to discuss these findings or further progress, please feel free to contact me.

Kevin Lahmers, DVM, PhD, DACVP
Virginia Tech University
klahmers@vt.edu
540-231-7632