Determination of the infectious titer and virulence of an original US porcine epidemic diarrhea virus PC22A strain

Abstract

The infectious dose of a virus pool of original US PEDV strain PC22A was determined in 4-day-old, cesarean-derived, colostrum-deprived (CDCD) piglets. The median pig diarrhea dose (PDD 50) of the virus pool was determined as 7.35 log 10 PDD 50 /mL, similar to the cell culture infectious titer, 7.75 log 10 plaque-forming units (PFU)/mL. 100 PDD 50 caused watery diarrhea in all conventional suckling piglets (n∈=∈12) derived from a PEDV-naive sow, whereas 1000 and 10 000 PDD 50 did not cause diarrhea in piglets derived from two PEDV-field exposed-recovered sows. This information is important for future PEDV challenge studies and validation of PEDV vaccines.