Cook, A. molecular weight limit, 10,000) (15). Antigen quality control was performed by ELISA using well-defined human serum samples of patients with different helminthic diseases. The specificity of the ELISA was assessed by WB, where two low-molecular-mass bands of 30 to 32 kDa were considered specific (11, 14). Of 3,247 serum samples, 87 were positive for by initial ELISA screening, 79 of which were positive by confirmatory WB analysis (Table ?(Table1).1). Hence, the overall prevalence among study individuals was 2.4%. No WB negatives were detected among samples with an ELISA cutoff above 0.800. Of the 79 serostatus. Therefore, the reported data on seropositivity in this population segment are likely to more or less reflect the overall background seroprevalence in Denmark. Sera from males and females in other age groups (Table ?(Table1)1) more likely represented samples from symptomatic individuals. Not surprisingly, these groups of individuals taken together had an approximately fourfold-higher prevalence of toxocariasis than the pregnant women, which does not necessarily indicate a higher prevalence of disease but does indicate higher exposure and risk. The assumption that the women aged 20 to 39 years included in the study represent the general background population (i.e., both males and females) is primarily based on the observation that a gender-related difference in prevalence Sildenafil citrate among the other age groups could not be detected (Table ?(Table11). To our knowledge, this is the first study on the seroprevalence in Denmark. Limited data on the background seroprevalence in European countries are available. A prevalence of 6.6% was found among 201 healthy Italian individuals (12). Havasiov et al. (6) reported a prevalence of 13.65% among healthy Slovakian blood donors, whereas Strchler et al. (16) and Jacquier et al. (7) demonstrated prevalences of 5% and 4% among Swiss blood donors, respectively. Data from the analysis of Swedish sera from 323 healthy individuals and 175 patients with clinical signs and symptoms, such as eosinophilia and ocular, pulmonary, hepatic, or neurological disorders revealed seroprevalences of 7% and 25%, respectively (10). The present data corroborate a significant difference in seroprevalence between the background Sildenafil citrate population and patient Sildenafil citrate segments. However, the background prevalence in the present study, based on women between 20 and 39 years of age, was 1 to 2% and was not nearly as high as in the Swedish study, which might partly be explained by a difference in the dilution of sera used in the ELISA screening and the fact that WB was not used in the Swedish study. It is also likely that samples from asymptomatic individuals used in the Swedish study represented another type of study material that is not immediately comparable with the present material. Data from an American study have shown Rabbit Polyclonal to TCEAL4 that persons infected with are more likely to be infected with (8). The seropositivity of among the among pregnant women in Denmark reported by Lebech et al. (9). It is possible that the majority of European infections are contracted upon the ingestion of raw or undercooked antigen. Lis Lykke Wassmann, Laboratory of Parasitology, Statens Serum Institut, Copenhagen, Denmark, is thanked for excellent technical assistance. Footnotes ?Published ahead of print on 29 July 2009. REFERENCES 1. Cook, A. J., R. Sildenafil citrate E. Gilbert, W. Buffolano, J. Zufferey, E. Petersen, P. A. Jenum, W. Foulon, A. E. Semprini, D. T. Dunn, et al. 2000. Sources of Toxoplasma infection in pregnant women: European multicentre case-control study. BMJ 321:142-147. [PMC free article] [PubMed] [Google Scholar] 2. Despommier, D. 2003. Toxocariasis: clinical aspects, epidemiology, medical ecology, and molecular aspects. Clin. Microbiol. Rev. 16:265-272. [PMC free article] [PubMed] [Google Scholar] 3. Duus, L. M., A. V. Christensen, D. Navntoft, B. Tarp, H. V. Nielsen, and E. Petersen. 2009. The infection in the Slovak Republic. J. Helminthol. 67:291-296. [PubMed] [Google Scholar] 7. Jacquier, P., B. Gottstein, Y. Stingelin, and J. Eckert. 1991. Immunodiagnosis of toxocarosis in humans: evaluation of a new enzyme-linked immunosorbent assay kit. J. Clin. Microbiol. 29:1831-1835. [PMC free article] [PubMed] [Google Scholar] 8. Jones, J. L., D..