Canine Lyme borreliosis is often difficult to diagnose with traditional methods. An in-office ELISA test kit that uses a synthetic peptide (C6) that duplicates the sequence of the IR6 region is now available. A study was conducted to evaluate the usefulness of this test in vaccinated and unvaccinated dogs. All dogs were client owned and were tested for exposure to Borrelia burdorferi during routine heartworm screening. Based on the results of the in-office C6 ELISA diagnostic test, dogs were designated seropositive or seronegative. Confirmation was made by whole-cell ELISA and western blot assays. The dogs were further divided by vaccination status into six groups, three groups each for seronegative and seropositive dogs. The groups for seronegative dogs were nonvaccinated, vaccinated upon entry into the study (two doses), and vaccinated before and after entry into the study; and seropositive dogs were nonvaccinated controls, vaccinated upon entry into the study (two doses), and vaccinated before and after entry into the study.

COMMENTARY: This in-office test can be used to determine infection status regardless of the animal's vaccination history. In this study, sensitivity and specificity were 100% in all six groups. The test yielded negative results in dogs that had been vaccinated and contained anti-B. burgdorferi antibody from vaccination. This may be helpful information for the clinician both for diagnostic purposes and for managing immunization programs. Funding for this study was provided by IDEXX Laboratories, Westbrook, ME.

Utility of an in-office C6 ELISA test kit for determination of infection status of dogs naturally exposed to Borrelia burgdorferi. Levy S, O'Connor TP, Janscom JL, Shields P. Veterinary Therapeutics 3:235-243, 2002.