[Efficacy of two gene species in the serological diagnosis of Borrelia burgdorferi infections]

Abstract

Background: There is phenotypic and genetic variability among the species Borrelia burgdorferi that produces Lyme disease. Three gene species and seven serotypes have been defined.

Aim: To study the efficacy of two gene species in the serological diagnosis of Borrelia burgdorferi infections in Granada, Spain.

Material and methods: One thousand sixty nine sera coming from 1,251 subjects without Lyme borreliosis were analyzed. These subjects were studied for health or pregnancy controls, differential diagnosis of viral disease, diagnosis of syphilis, neurological or rheumatic diseases. In all samples, antibodies against Borrelia burgdorferi (B31 and Pko strains) and against Treponema pallidum were investigated. Screening tests (ELISA and hemagglutination) were followed by confirmations tests for positive samples (Western Blot IgG strain B31 and FTA-abs respectively). A clinical and laboratory follow up was done for subjects with positive serological tests.

Results: The global rate of positive antibodies against Borrelia burgdorferi B31 was 8.31% and against the strain Pko was 0.64%. Western blot was negative in 36% of subjects with positive ELISA B31. The distribution of antibodies against the strain B31 was acute herpes virus infection in 16%, gestation in 3%, HIV infection in 6.4%, T pallidum infection in 36%, rheumatic diseases in 25%, neurological diseases in 17.5% and health controls in 7.4%. The percentage of positive Western Blot analyzes were 0.8, 2.1 and 0.4% respectively. A reversion of positive ELISA tests was observed in 6 subjects.

Conclusions: The disparity in rates of antibodies against Borrelia burgdorferi in different geographic regions may be due to differences in the serological tests used. The high rate of false positive ELISA tests underscores the need to use other serological tests.