The bentonite flocculation test in the serology of tuberculosis. II. Detection of tuberculosis in cattle.

Abstract

A survey of sera from both healthy and tuberculous cattle was made using bentonite sensitized with human old tuberculin (OT) and with a purified BCG carbohydrate antigen (BCG F1). Nine hundred and ninety-five tuberculin-negative and 141 tuberculin-positive reactor cattle were tested. While 52% of the tuberculin-negative cows gave a positive flocculation test with the OT antigen, only 4% reacted with the BCG F1 antigen. Both the proportion of positive titers and the means of titers showed that, regardless of the antigen with which bentonite is sensitized, there is a significant correlation between increase in bentonite titer and the severity of infection in the tuberculin-positive cows, even though the sera from a number of cows—shown on postmortem to have visible lesions—did not give any titer with either bentonite antigen.