Klaus Nielsen


Affiliation: Canadian Food Inspection Agency
Country: Canada


  1. Nielsen K, Gall D, Bermudez R, Renteria T, Moreno F, Corral A, et al. Field trial of the brucellosis fluorescence polarization assay. J Immunoassay Immunochem. 2002;23:307-16 pubmed
    ..1% and the relative specificity of the FPA(bld) was 99.6%. These results compared favourably with those obtained using the other serological tests. ..
  2. Nielsen K. Diagnosis of brucellosis by serology. Vet Microbiol. 2002;90:447-59 pubmed
  3. Nielsen K, Smith P, Yu W, Nicoletti P, Elzer P, Vigliocco A, et al. Enzyme immunoassay for the diagnosis of brucellosis: chimeric Protein A-Protein G as a common enzyme labeled detection reagent for sera for different animal species. Vet Microbiol. 2004;101:123-9 pubmed
    ..An added advantage was that a universal cut-off for all tests using the proteins A and G detection reagent could be established, simplifying diagnostic interpretation of the data. ..
  4. Nielsen K, Smith P, Yu W, Elmgren C, Nicoletti P, Perez B, et al. Second generation competitive enzyme immunoassay for detection of bovine antibody to Brucella abortus. Vet Microbiol. 2007;124:173-7 pubmed
    ..The performance characteristics, sensitivity, specificity and exclusion of B. abortus S19 vaccinated animals, of the assay were very similar to those of the classical CELISA. ..
  5. Nielsen K, Smith P, Yu W, Halbert G. Salmonella enterica Serotype Urbana Interference with Brucellosis Serology. J Immunoassay Immunochem. 2007;28:289-96 pubmed
    ..enterocolitica O:9 but all were strongly positive in the FPA using OPS from E. coli O:157 while seven sheep had titers to S. enterica serotype Urbana. The impact on diagnostic serology for brucellosis is discussed. ..
  6. Nielsen K, Smith P, Yu W, Elmgren C, Halbert G, Nicoletti P, et al. Validation of a second generation competitive enzyme immunoassay (CELISA) for the diagnosis of brucellosis in various species of domestic animals. Vet Immunol Immunopathol. 2008;125:246-50 pubmed publisher
    ..Sufficient samples from cattle, swine, sheep and goats to validate the test were included based on OIE guidelines suggesting inclusion of a minimum of 300 positive and 1000 negative samples. ..
  7. Nielsen K, Smith P, Widdison J, Gall D, Kelly L, Kelly W, et al. Serological relationship between cattle exposed to Brucella abortus, Yersinia enterocolitica O:9 and Escherichia coli O157:H7. Vet Microbiol. 2004;100:25-30 pubmed
    ..coli O157:H7, Y. enterocilitica O:9 and B. abortus is dependent on the test used. Thus, extensive cross reaction was observed with the IELISA with much less reactivity in the FPA and the CELISA...
  8. Nielsen K, Smith P, Yu W, Rojas X, Perez B, Conde S, et al. Detection of ovine antibody to Brucella ovis by indirect enzyme immunoassay. J Immunoassay Immunochem. 2007;28:243-50 pubmed
    ..Because of the batch uniformity of the B. abortus RB51 RLPS and the versatility of the protein A/G-enzyme conjugate, the latter version appears to be the most useful for diagnostic serology...
  9. Nielsen K, Smith P, Conde S, Draghi De Benitez G, Gall D, Halbert G, et al. Rough lipopolysaccharide of Brucella abortus RB51 as a common antigen for serological detection of B. ovis, B. canis, and B. abortus RB51 exposure using indirect enzyme immunoassay and fluorescence polarization assay. J Immunoassay Immunochem. 2004;25:171-82 pubmed
    ..B. abortus RB51 core labeled with fluorescein resulted in sensitivity and specificity values of 93.5% and 99.8%, respectively, with bovine sera and 78.1% and 99.0% with sheep sera. It was not possible to test the dog sera in the FPA...

More Information


  1. Nielsen K, Smith P, Yu W. Detection of anti-Brucella antibodies in llama (Llama glama). J Immunoassay Immunochem. 2007;28:61-6 pubmed
    ..8% to 100% specific although some sera gave an 'agglutination like' reaction after about 10 minutes of incubation. The complement fixation test could not be used, as 31% of the sera were anticomplementary and 4% were false positive. ..