Antibodies against Borrelia burgdorferi in Bavarian forest workers.

The sera of 496 forest workers (fw), 44 customs officials and 20 other persons in outdoor professions from different areas of Bavaria were tested for antibodies against Borrelia burgdorferi (strain B 31) by indirect immunofluorescence. In sera previously absorbed with Treponema phagedenis ultrasonicate, significantly elevated IgG antibody titers were found in 69 cases, in 68 fw (13.7%) and 1 custom agent. In accordance with previous observations the distribution of positive results showed a distinct age dependance: under 24 years (y) 1.6% (n = 64), 25-34 y 0 (n = 30), 35-44 y 10.1% (n = 79), 45-54 y 17.4% (n = 190). Infections without manifest illness seem to predominate. In 1 area the number of positive persons was significantly higher than in the other: In Donauries near Illertissen 14 (45%) of 31 probands had elevated IgG titers. This area and the high level regions excepted, no significant differences were demonstrable amongst the 13 regions of Bavaria included in this investigation.