Scandinavian Journal of Infectious Diseases
ISSN: 0036-5548 (Print) 1651-1980 (Online) Journal homepage: http://www.tandfonline.com/loi/infd19
Antibodies to Borrelia burgdorferi in Various Population Groups in Croatia Vitomir Burek, Ljiljana Mišić-mayerus & Tomislav Maretic To cite this article: Vitomir Burek, Ljiljana Mišić-mayerus & Tomislav Maretic (1992) Antibodies to Borrelia burgdorferi in Various Population Groups in Croatia, Scandinavian Journal of Infectious Diseases, 24:5, 683-684, DOI: 10.3109/00365549209054658 To link to this article: http://dx.doi.org/10.3109/00365549209054658
Published online: 08 Jul 2009.
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Date: 30 March 2016, At: 00:13
Scand J Infect Dis 24: 683-684, 1992
Antibodies to Borrelia burgdorferi in Various Population Groups in Croatia VITOMIR BUREK', LJILJANA MISIC-MAYERUS2and TOMISLAV MA RETIC]
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From the Departments of 'Clinical Immunology, University Hospital of Infectious Diseases, Zagreb, and 'lnfecrology, Medical Center, Koprivnica, Croatia The purpose of the present study was to investigate the prevalence of antibody to Borrelia burgdorferi in Croatia in various population groups. The study comprised 263 individuals: 93 healthy subjects (travellers); 100 controls separated into 2 subgroups, 50 from high risk zone (endemic)and 50 from low risk zone (non-endernic);and 70 members of a high risk population (forestry workers). Antibody to B. burgdorferi of IgM and IgG class were analysed by an ELISA technique using mixed antigen made of strain B31 (ATCC 35210). IgG antibodies were detected in 9/93 (9.7%) in general population; 22/50 (44.0%) in the control group from high risk zone and 4/50 (8.0%) from low risk zone; and 30170 (42.9%) among forestry workers. In all tested groups low numbers of IgM positive were found. V . Burek, MD, PhD, Department of Clinical Immunology, University Hospital of Infectious Diseases, Mirogojska 8, 41 000 Zagreb, Croatia
INTRODUCTION Lyme disease has been diagnosed in Croatia since mid 80ies (1). However there is hardly any knowledge about the frequency of this infection in the general population and among inhabitants of areas with high risk for tick-bite. The aim of the present study was to investigate the prevalence of antibody to Borrelia burgdorferi in Croatia in the general population, a control population and a high risk population.
MATERIALS AND METHODS Grneral population. This group consisted of 93 healthy subjects. They were all travellers, who needed anti-HIV and other testing for health documentation. 79 were males and 15 females, mean age 35.8 years, range 2348. No one was anti-HIV positive. Control popularion. 100 patients with various diseases but lacking clinical evidence of an active B. burgdorferi infection were used as controls. They were divided into 2 subgroups. First subgroup (SO patients, 25 male, 25 female, mean age 37.2 years, range 1 M 3 ) lived in a few villages in a tick-bite endemic area, Koprivnica distric. This area is about 80 km north-east of Zagreb. The villages are surrounded by forest in which many inhabitants spend much of their leisure time looking for mushrooms and gathering woods. Second subgroup consisted of people from a non-endemic area, Zagreb district (50 patients, 25 male, 25 female, mean age 35.7 years, range 10-61). Risk population. This group consisted of 70 healthy forestry workers, all men aged 2 5 4 8 years (mean 36.3). All of them answered a questionnaire, designed to assess the extent of exposure to tick-bites and report possible symptoms of Lyme disease. The exposure rate to tick-bites was exceptionally high. Multiple tick-bites were registered in every person. They were working in the national forest located in the northern part of Koprivnica district-area close to the already mentioned endemic zone for the first control subgroup. Antibody determination. Antibodies to B. burgdorferi of IgM and IgG class were detected by ELISA technique (Virotec). Antigen used in this ELISA test was a mixed antigen made of the strain B31 (ATCC 35210). Optical density was measured by microplate photometer and net absorbance values > 0.45 for IgG and > 0.40 for IgM were graded as positive.
RESULTS General population. 3/93 (3.2%) were positive for IgM and 9/93 (9.7%) for IgG class of antibody to B. burgdorferi (Table I).
V. Burek et al.
Scand J Infect Dis 24
Table I. Antibodies to Borrelia burgdorferi of IgM and IgC class in sera of different population groups Population group
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General population Control population High risk zone Low risk zone Risk population Forestry workers
No. of persons
Conrroi popularion. A significant difference in the prevalence of IgG antibodies between individuals from the endemic area (44%) and from the non-endemic area was seen (8%). The percentage of IgM antibodies was similar in both groups.
Risk population. 30/70 forestry workers (42.9%) were found to be IgG positive and only 1 (1.4%) IgM positive. Clinical illness among the members of this group corresponding with Lyme disease was unusual. although about 30% of them gave a history of rash considered typical of erythema migrans.
DISCUSSION The seroprevalence in the general populations (9.7%) was approximately the same as in the control group from the non-endemic zone in the Zagreb area (8.0%). Both results are comparable to those reported in similar studies in Sweden: Stiernstedt et al. (2) and Gustafson et al. (3) found in the non-endemic area of Stockholm 9% seropositivity among control individuals. The seropositivity in our control population from the endemic Koprivnica area was, however, almost double as high as in Swedish endemic areas: 44% vs 26%. In our group of 70 forestry workers, who had a high occupational risk of tick-bite, we found a seropositivity as high as 42.9%. In reports from some European countries (Germany, Switzerland, England) a seroprevalence among individuals with high risk for tick-bites (forestry workers, farmers, trackfinders), the prevalence has been 1 6 2 5 % (4-7). In some isolated groups of forestry workers, however, this percentage increases to 35% (8) and 55% (5). Our results are similar to those of Neubert et al. (9) in Germany who noted a seroprevalence of 33.6% among forestry workers. Our study confirmed earlier reports that subclinical illness or asymptomatic seroconversion may occur in persons exposed to the borrelia spirochete (2, 3, 9).
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4. Farfer H, Sauvain MJ, van der Linden S, Zhioua E, Gern L, Aeschliman A. Pravalenz der Lyme-Borreliose in einer Schweizerischen Risiko-Population. Schweiz Med Wochenschr 118: 6 5 4 9 , 1988. 5. Guy EC. Bateman DE, Martyn CN, Heckels JE, Lawton NF. Lyme disease: Prevalence and clinical importance of Borrelia burgdorferi specific IgG in forestry workers. Lancet 1: 484486, 1989. 6. Morgan-Capner P, Cutler SJ, Wright DJM. Borrelia burgdorferi infection in UK workers at risk of tick bites. Lancet 1: 789-790. 7. Miinchhoff P, Wilske B, Preac-Mursic V, Scierz G. Antibodies against Borrelia burgdorferi in Bavarian forest workers. Zentralbl Bakteriol Mikrobiol Hyg (A) 263: 412419, 1986. 8. Hedberg CW, Osterholm MT, MacDonald KL, White KE. An interlaboratory study of antibody to Borrelia burgdorferi. J Infect Dis 155: 1325-1327, 1987. 9. Neubert U, Munchoff P, Volker B. Borrelia burgdorferi infections in Bavarian forest workers. Ann N Y Arnd Sci 588: 47-79.