severe clinical signs of eia were noted in the ponies at each serial passage , but the mean virulence rating of each passage , graded on frequency of febrile episodes and number of clinical signs evident within 200 days after ponies were inoculated , increased from 0 through 4 , 21 , 24 , and 29 for the 1st through 5th serial passages , respectively .
C0015967
febrile
C3540840
clinical