1. Lecture 11 serology Lyme’s Disease
Dr. Dalia Galal

2. Introduction
Lyme disease was named in 1977 when arthritis was observed in a cluster of children in and around Lyme, CN
Conditions suggested that this was an infectious disease probably transmitted by an arthropod
Further investigation revealed that Lyme disease is caused by the bacterium

3. Causative Organism Borrelia burgdorferi Loosely coiled spirochete
8-20 micrometers

4. Vector Ixodes ticks are much smaller than common dog and cattle ticks
Below adult female, adult male, nymph, and larva on a centimeter scale.
Humans acquire disease from bite of nymphal or adult tick.

5. Three Stages of Disease
Localized rash – erythema chronicum migrans (chronic migrating redness)
Dissemination to multiple organ systems
Chronic disseminated stage often with arthritic symptoms

6. Localized Rash (chronic migrating redness)

7. Dissemination
Signs of early disseminated infection usually occur days to weeks after the appearance of a solitary erythema migrans lesion
Neurologic – Bell’s Palsy
Musculoskeletal manifestations may include migratory joint and muscle pains
Late disseminated Lyme disease is intermittent swelling and pain of one or a few joints.

8. Chronic Disseminated Chronic arthritis Chronic axonal polyneuropathy
Lyme disease morbidity may be severe, chronic, and disabling.
Rarely, if ever, fatal

9. Diagnosis Diagnosed clinically, confirmed serologically.
Often appropriate to treat patients with early disease solely on the basis of objective signs and a known exposure.
CDC recommends testing initially with a sensitive first test, ELISA or an immunofluorescence assay (IFA) test, followed by testing with the more specific Western immunoblot (WB) test to corroborate equivocal or positive results obtained with the first test.

10. Serology
Patients with early disseminated or late-stage disease usually have strong serological reactivity
Antibodies often persist for months or years following successfully treated or untreated infection.
seroreactivity alone cannot be used as a marker of active disease

11. Problems with Serology
IFA false positive may occur if patient has syphilis, relapsing fever or reumatoid arthritis (RA).
IFA interpretation highly subjective
Enzyme immunoassay (EIA) lacks sensitivity in early disease.
EIA false positives with syphilis, other treponemes, and autoimmune disease.

12. Western Blot
Must be used if the Lyme IgG/IgM antibody serology is equivocal or positive
"Osp" refers to outer surface protein of the bacteria.
"kDa" is the abbreviation for "kilodalton," which is used for molecular weight designations.
Lyme antibodies of importance are against the following molecular weights of the B. burgdorferi antigens: kDa (Osp C); 31 kDa (Osp A); 34 kDa (Osp B); 39 kDa; 41 kDa; and kDa7.

13. Lane 1, monoclonal antibodies defining selected antigens to B
Lane 1, monoclonal antibodies defining selected antigens to B. burgdorferi Lane 2, human serum (IgG) reactive with the 10 antigens scored in the currently recommended criteria for blot scoring; lines indicate other calibrating antibodies. Molecular masses are in kilodaltons.

14. Treatment Single dose doxycycline shortly after tick bite.
Lyme disease give doxycycline followed by amoxacillin
Neuroborreliosis requires IV antibiotic therapy.