Dr. Stafford Tick Management Handbook - Newtown, CT

StaffordDiagnosis and treatment of Lyme diseaseThe Connecticut Agricultural Experimentation StationA physician should be consulted if Lyme disease is suspected. Only the rash is distinctiveenough for a clinical diagnosis without laboratory con. rmation. In the absence of an EM rash, Lymedisease may be dif. cult to diagnose because its symptoms and signs vary among individuals andcan be similar to those of many other diseases. Conversely, other arthritic or neurologic diseasesmay be misdiagnosed as Lyme disease. Lymedisease is probably both over-diagnosed andunder-diagnosed with groups of patients, someof whom without Lyme disease convinced theyhave it while other patients with the diseasebeing told they do not have it. A blood test todetect antibodies to Lyme disease spirochetes(serological testing) can support or con. rm theclinical diagnosis of the disease. Antibodiesto Borrelia antigens (parts of the bacteriarecognized by the immune system) usuallycannot be detected until 3-4 weeks after onset 54of disease. Therefore, tests are not reliableenough to be used as the sole criterion for a diagnosis during the early stages of the disease. Testscan give false-negative and false-positive results. Newer tests are more speci. c, greatly reducingfalse positive reactions. Reliability of the test improves dramatically in the later stages of thedisease as serological reactivity increases, although inaccurate results may still occur. Patients withneurologic or arthritic Lyme disease almost always have elevated antibody concentrations.Two stage serological testing for Lyme disease is suggested by many public health organizations:• Stage One: A relatively sensitive screening method by enzyme-linked immunosorbentassay (ELISA) or indirect . uorescent antibody (IFA) test. If negative, no further testing isdone. Testing at the time of the Lyme disease rash is unnecessary as many will be negative.Antibiotic treatment early in infection may abrogate the antibody response. An ELISAprovides a quantitative measure of antibody levels (measurable color reaction) and for rapidtesting of large numbers of samples. An ELISA measures the reaction to all the antigens indisrupted Borrelia or to recombinant antigens, but does not allow identi. cation of whichantigens are being bound by antibody and can yield false positives from cross-reactiveantibodies. ELISA using the C6 peptide of the VslE protein antigen, another surface proteinof B. burgdorferi that elicits a strong response by the immune system, may be as sensitiveand selective as the two-stage testing procedure.• Stage Two: If the . rst test is positive or equivocal, a more speci. c Western immunoblot testis performed to simultaneously demonstrate an antibody response to several B. burgdorferiantigens (i.e., proteins recognized by the immune system), which show up as bands on theblot. The Lyme disease spirochete has numerous immunogenic proteins including outersurface proteins (OspA, OspB, and OspC), the 41 kDa antigen on the internal . agellum,and at least 9 other prominent antigens. The Western blot is labor intensive and requiresa subjective interpretation of the results. Although there is an established criterion for apositive blot, there is some disagreement on the number and speci. c “bands” required for apositive test.Lyme disease can be treated with one of several types of antibiotics, including tetracyclines, mostpenicillins, and many second- and third-generation cephalosporins (e.g., doxycycline, amoxicillin,Bulletin No. 1010 25