Treponema paraluis-cuniculi infection in a commercial rabbitry: epidemiology and serodiagnosis

The epidemiology of Treponema paraluis-cuniculi infection in a commercial rabbit breeding facility was described using several serologic tests. The Venereal Disease Research Laboratory, rapid plasma reagin, microhemagglutination and fluorescent treponemal antibody-absorption tests were used to detect antibodies to T paraluis-cuniculi. Young adult New Zealand white rabbits, tested prior to entry into the breeding program, were nearly always free of T paraluis-cuniculi infection. In adult females, the prevalence of T paraluis-cuniculi infection increased with parity; females para 6 or greater were usually seropositive. Most adult males seroconverted within 6 months of entering the breeding program; all males were seropositive after 12 months in the breeding program. This suggested that T paraluis-cuniculi spreads mainly by horizontal transmission during breeding in adult rabbits. Of the two nontreponemal antigen tests used, the Venereal Disease Research Laboratory test was more sensitive, whereas the rapid plasma reagin test was more specific in detecting T paraluis-cuniculi infection; the fluorescent treponemal antibody-absorption test was used as the confirmatory treponemal antigen test. However, neither nontreponemal antigen test was completely satisfactory. On the other hand, the sensitivity and specificity of the microhemagglutination test compared favorably with the fluorescent treponemal antibody-absorption test. Since the microhemagglutination test combines desirable features of both a screening and verification procedure, it should be the test of choice for detection of T paraluis-cuniculi infection.