Confirmation that the dog is a definitive host for Neospora caninum

Two mixed-breed littermate dogs were fed mouse brains containing tissue cys ts of the NC-beef isolate of Neospora caninum. Both dogs excreted N. caninu m oocysts in their feces, Dog 1 which was given methylprednisolone acetate (MPA) prior to ingesting tissue cysts, excreted oocysts on days 5 to 10 inc lusive and on day 17 after ingesting tissue cysts. Dog 1 had a serum antibo dy titer of 1 :200 in the indirect fluorescent antibody test (IFAT) 35 days after it was fed tissue cysts. Dog 2, which was not treated with MPA, excr eted oocysts on Day 6 and Day 9 after ingesting tissue cysts. Antibodies to N. caninum were not found in a 1,25 dilution of serum on any examination p eriod for Dog 2 during the study. Neospora caninum was not found in the tis sues of either dog by histological or immunohistochemical means following n ecropsy 42 days after being fed tissue cysts. The identity of the oocysts e xcreted in the feces of the dogs was confirmed by mouse inoculation studies , (C) 1999 Elsevier Science B.V, All rights reserved.