Enzyme immunoassay detection of antibodies in canine blastomycosis using Blastomyces dermatitidis lysate antigens.

A Blastomyces dermatitidis yeast phase lysate antigen (T-58) prepared in our laboratory was used in an enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies in 201 serum specimens from dogs with blastomycosis. In addition 36 sera from non-infected dogs from an endemic area for blastomycosis and 36 sera from non-infected dogs residing in a blastomycosis non-endemic area were assayed. Sensitivity values ranged from 96.2% (53 pre-treatment sera) to 88.5% (148 post-treatment sera) with the specimens from dogs with confirmed blastomycosis. Minimal reactivity was experienced with the sera from non-infected dogs. Positive reactions were obtained with 8.3% of the endemic area sera and with 5.6% of the sera from the non-endemic area. Mean ELISA index values ranged from 7.66 with the pretreatment sera to 1.11 and 1.03 with the endemic area sera and non-endemic area specimens respectively.