Figure 2. Pathogenicity comparison among the Em2007, CH-1a, and WUH1 strains of porcine reproductive and respiratory syndrome virus (PRRSV). Forty-day-old piglets (9 piglets in each group) free of PRRSV were inoculated intramuscularly with 105.0 mean tissue culture infectious doses/2 mL of Em2007, CH-1a, WUH1, respectively. Two piglets from each group were euthanized and necropsied at 7 and 10 days postinoculation (dpi) for viral load analyses and histopathologic examinations. The remaining 5 piglets in each group were used to evaluate rate of death. Mean rectal temperature (A) and survival rate (B) of each group were recorded for 21 dpi.
The opinions expressed by authors contributing to this journal do not necessarily reflect the opinions of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.