|Rowland, R r r|
Submitted to: Porcine Reproductive and Respiratory Syndrome International Symposium
Publication Type: Abstract only
Publication Acceptance Date: 9/8/2005
Publication Date: 12/20/2005
Citation: Molina, R.M., Hermann, J., Rowland, R., Christopher-Hennings, J., Nelson, E., Lunney, J.K., Yoon, K., Zimmerman, J. 2005. Management of PRRS persistence: identification of persistently infected swine. [sbstract]. Porcine Reproductive and Respiratory Syndrome International Symposium. p. 66. Available: http://www.prrssymposium.org/Documents/2005%20International%20PRRS%20Symposium%20-%20Proceedings.pdf Interpretive Summary:
Technical Abstract: The objectives of this experiment were to (1) establish a better estimate of the proportion of PRRSV carriers over time and (2) identify virological or immunological correlates of persistent infection or immunity for diagnostic use. 109 2-week-old pigs were inoculated with PRRSV ATCC VR-2332; 56 age-matched animals served as uninoculated controls. Infected animals were housed in a single room (648 ft2) until PID 40, then split between two rooms. Serum and whole blood were collected at 2 week intervals through post inoculation day (PID) 202. On approximately the same sampling schedule, a subset of pigs were euthanized and 18 tissues collected for analysis, with the final necropsy on PID 203. Immediately following collections, samples were shipped first priority overnight to collaborating laboratories. PCR results on tonsil samples showed the following pattern of persistent infection: DPI 7 28 42 56 84 98 112 119 133 147 161 175 189 PCR+ 3 3 3 3 2 3 1 5 6 3 3 2 1 N 3 3 3 3 2 3 3 10 10 10 10 10 10 Additional results are forthcoming, but persistent infection in a low percentage of the population beyond 200 DPI appears to be a certainty.