Study of a Cohort of 1,886 Persons To Determine Changes in Antibody Reactivity to Borrelia burgdorferi 3 Months after a Tick Bite

Abstract

Lyme borreliosis is a tick-borne disease caused by the bacterium Borrelia burgdorferi. The most frequent clinical manifestation is a rash called erythema migrans. Changes in antibody reactivity to B. burgdorferi 3 months after a tick bite are measured using enzyme-linked immunosorbent assays (ELISAs). One assay is based on native purified flagellum antigen (IgG), and the other assay is based on a recombinant antigen called C6 (IgG or IgM). Paired samples were taken at the time of a tick bite and 3 months later from 1,886 persons in Sweden and the Åland Islands, Finland. The seroconversion or relative change is defined by dividing the measurement units from the second sample by those from the first sample. The threshold for the minimum level of significant change was defined at the 2.5% level to represent the random error level. The thresholds were a 2.7-fold rise for the flagellar IgG assay and a 1.8-fold rise for the C6 assay. Of 1,886 persons, 102/101 (5.4%) had a significant rise in antibody reactivity in the flagellar assay or the C6 assay. Among 40 cases with a diagnosis of Lyme borreliosis, the sensitivities corresponding to a rise in antibodies were 33% and 50% for the flagellar antigen and the C6 antigen, respectively. Graphical methods to display the antibody response and to choose thresholds for a rise in relative antibody reactivity are shown and discussed. In conclusion, 5.4% of people with tick bites showed a rise in Borrelia-specific antibodies above the 2.5% threshold in either ELISA but only 40 (2.1%) developed clinical Lyme borreliosis. Borrelia burgdorferi sensu lato is transmitted by hard ticks (Ixodes ricinus or Ixodes persulcatus) throughout Europe, especially in the temperate climate zone. Both the vector and the bacterium are prevalent in southern Scandinavia, and ticks frequently attach to humans and occasionally transmit B. burgdorferi (1-4). Lyme borreliosis (LB) is also common in parts of the United States. The term B. burgdorferi sensu lato denotes a species complex belonging to the genus Borrelia and is herein designated simply B. burgdorferi or Borrelia. The most frequent species infecting humans in Europe are B. afzelii, B. garinii, and B. burgdorferi sensu stricto. In the United States, the only prevalent species is B. burgdorferi sensu stricto. The infections may involve the nervous system, the skin, the joints, and the heart. The most frequent manifestation is a characteristic skin lesion called erythema migrans (EM).This study was based on data from the tick-borne diseases (TBD) STING study (www.stingstudien.se). Ticks that had bitten humans in the Åland Islands, Finland, and different parts of Sweden were collected and analyzed at Linköping University (2-5). The focus of this study was to analyze the differences in the measurements of B. burgdorferi-specific antibodies in the paired samples and propose methods for detecting changes in antibody reactivity. Although the concept of antigen-induced stimulation and seroconversion has broad application in diagnostic medicine, epidem...

Lyme borreliosis and other tick-borne diseases. Guidelines from the French scientific societies (II). Biological diagnosis, treatment, persistent symptoms after documented or suspected Lyme borreliosis

“…A Swiss longitudinal study (1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993) of 305 patients infected with Borrelia burgdorferi sensu lato, with a positive Lyme serology but without any initial clinical signs, reported that more than 95% of patients remained asymptomatic at seven years of follow-up [2]. A prospective Scandinavian study showed that, in the absence of prophylaxis and within three months following a tick bite, 5.4% of patients (102/1,886) achieved seroconversion, with clinical signs of Lyme borreliosis in 39.2% of cases (40/102) [18].…”