FIG. 4.

Comparison of peptides C₆ and Ct for detection of B. burgdorferi infection in dogs. Thirty-three dogs (dogs 1 to 33) were infected by tick inoculation. Eighteen sera (sera 40 to 57) were collected from dogs clinically diagnosed with Lyme disease. Antibody levels to IR₆ and the C-terminal invariable domain were assessed using C₆ and Ct ELISAs, respectively. The cutoff value (OD = 0.113) was defined as the mean OD plus 3 standard deviations of 10 serum samples from healthy dogs from an area where Lyme disease is not endemic, when the two peptides were separately used as ELISA antigens.