It is demonstrated by numerous examples in the medical literature that a present or previous Borrelia infection can be present in just about any person. For instance in a Dutch trial a positive sero-reaction for the Borrelia burgdorferi sensu lato strains was found in 6 percent of blood donors (28). In other trials the antibody of Borrelia burgdorferi could also be found in 4 percent of the blood of healthy volunteers (29), while the prevalence in the general population was between 7 and 29 percent (30). This latter research followed the health of subjects for two years, and Lyme borreliosis developed in 4.6 percent and 3.2 percent of the subjects, in the first and second year respectively, which means that the clinical symptoms may not appear and the definite diagnosis may not be established until one or two years later. An Estonian research compared the infection rate of the Estonian population with healthy volunteers from Lapland, and it found that the rate of subclinical Lyme borreliosis was high among Estonians (31).
- Serological and molecular evidence for spotted fever group Rickettsia and Borrelia burgdorferi sensu lato co-infections in The Netherlands. Koetsveld J, Tijsse-Klasen E, Herremans T, Hovius JW, Sprong H. 2015., Ticks Tick Borne Dis.
- Seroprevalence of Borrelia burgdorferi and tick-borne encephalitis virus in a rural area of Samsun, Turkey. Aslan Başbulut E, Gözalan A, Sönmez C, Cöplü N, Körhasan B, Esen B, Akın L, Ertek M. 2012., Mikrobiyol Bul.
- Epidemiological studies of Lyme borreliosis and tick-borne encephalitis. R, Gustafson. 1994., Scand J Infect Dis Suppl.
- 31. Serological description of Estonian patients with Lyme disease, a comparison with control sera from endemic and non-endemic areas. Kisand KE, Utt M, Kisand KV, Prükk T, Uibo R. 2004., Int J Med Microbiol.