Serological testing for Borrelia by Western Blot is used to diagnose Lyme disease.
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Borrelia burgdorferi is responsible for Lyme disease (borreliosis). Borreliae are thin, flexible, helically coiled, and highly motile spirochetes. In Europe, Borreliae are transmitted mostly by the Ixodes Ricinus tick and in America by the Ixodes damini tick. The incubation period ranges from 3 to 30 days. If left untreated, the disease progresses through three stages, although the course of each patient often departs from this classic pattern.
Stage I: Four to eight weeks after the bite of the infected tick, the typical migratory erythema develops on the skin.
Stage II: Generalized abnormal symptoms appear after three weeks. Flu symptoms occur, and many patients may develop lymphocytic meningitis and radiculopathy (Bannwarth syndrome), staffing and aseptic meningitis, as well as arthritis and carditis episodes.
Stage III: Neurological disorders (chronic encephalomyelitis), chronic atrophic acrodermatitis (acrodermatitis chronica atrophicans), Lyme disease arthritis.
Lyme disease occurs throughout the northern hemisphere. There are some endemic outbreaks where the disease is more common, such as in central Europe, where approximately 3-7% of larvae and 10-34% of larvae and adult ticks are infected by Borrelia burgdorferi sensu lato. Various wild animals, such as rodents, and larger animals, such as deer, constitute the natural reservoir of Borrelia, although the disease rarely infects these species. The ticks feed by sucking the infected blood from these animals.
Western Blot
Western Blot Screening for Lyme Disease can detect two different classes of antibodies: IgM and IgG. IgM antibodies appear earlier, so this screening may help identify patients during the first few weeks of infection. The disadvantage of testing for IgM antibodies is that they can often give false-positive results. Testing for IgG antibodies is more reliable, but it may take 4-6 weeks for the body to produce them in sufficiently large quantities to be detectable by this test.
- Western Blot testing should not be performed without first determining total antibodies against Borrelia burgdorferi
- Western Blot testing should not be performed if total antibodies against Borrelia burgdorferi are negative
- Positive IgM Western Blot test only makes sense during the first four weeks of illness
- If the disease has been present for more than 4-6 weeks and the IgG Western Blot test is negative, the patient is unlikely to have Lyme disease, even if the IgM Western Blot test is positive.
