Eighty-six clinically normal adult dogs from southern Florida, USA, with no history of dermatitis, were intradermally skin tested with Greer flea antigen 1:1000 w/v to determine the prevalence of positive immediate intradermal reactivity. This study describes the test group of animals and reports the prevalence of sensitivity to the Greer whole-body flea antigen in normal dogs living in a flea-rich environment. Similar to previous research, the highest prevalence of reactivity to flea antigen occurred at 3-4 years of age. The results indicate that 24% of clinically normal dogs from a flea-rich environment exhibited positive immediate skin test reactivity. These dogs had no clinical signs of flea allergic dermatitis (FAD) in spite of ongoing flea exposure. A 2-year follow-up telephone call to the owners of these flea antigen intradermal skin test (IDST)-positive dogs indicated that only two of 21 dogs had developed clinical signs of FAD.
