HUMORAL RESPONSE OF DAIRY-CATTLE TO SPIROCHETES ISOLATED FROM PAPILLOMATOUS DIGITAL DERMATITIS LESIONS

Objective-To determine whether a humoral response against spirochetes isolated from papillomatous digital dermatitis (PDD) lesions is elicit ed in dairy cattle affected with PDD. Sample Population-41 cattle with PDD from 8 dairies (study population) and 30 cattle from 2 dairies fr ee of PDD (control population). Additionally evaluated were 32 cattle from a dairy with a past history of PDD but no current disease, and 52 cattle from a dairy with high prevalence of PDD, 25 with and 27 witho ut detectable lesions. Procedure-ELISA were used to evaluate the humor al response of all cattle to representative isolates from 2 groups of spirochetes of unknown species isolated from PDD lesions. Specificity of the response was evaluated, using immune sera prepared against each of the spirochetes, and by adsorption studies of immune and field ser a. The potential for confounding by an antibody response to other spir ochetes associated with diseases of cattle was assessed. Results-The a ntibody response (specific) to both PDD spirochete groups of cows with PDD was significantly increased, compared with that of cows from PDD- free dairies. There was no association between antibody response to PD D-associated spirochetes and antibody response to other spirochetal di seases of cattle. None of the cattle from the dairy with previous hist ory of PDD but without current disease were classified as test positiv e by either PDD ELISA. There was a significant (P < 0.01) difference i n classification results for both PDD ELISA for cattle with PDD from t he dairy with a high herd prevalence of PDD, compared with cattle with out detectable disease from the same dairy. Conclusions and Clinical R elevance-The humoral response in cattle with PDD lesions was significa ntly different from that in cattle without detectable lesions, thus pr oviding additional information regarding the potential role of spiroch etes isolated from PDD lesions in the etiopathogenesis of PDD.