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Background & objectives: Leptospirosis, a zoonosis with a worldwide distribution is an acute febrile illness caused by spirochaetes of the pathogenic Leptaspira interrogans. Microscopic agglutination test (MAT), the reference method for diagnosis was successively done in evaluate the modified ELISA which was developed with the recombinant LipL32 antigen for the detection of anti-leptospiral antibodies in human serum samples. Methods: The recombinant LipL32 antigen was developed from the serovar Pomona strain Pomona of the pathogenic L interrogans species. The predicted titre at a single working dilution was plotted against the observed antiserum titre. Subsequently, predicted antibody activity titres were determined directly from the standard curve by solving the regression line equation. The relative sensitivity, specificity and accuracy of the single dilution ELISA for the detection of anti-leptospiral antibodies were determined in comparison to the MAT. Results: A linear relationship was found between the predicted antibody titres at a single working dilution of 1:250 and the corresponding observed serum titres by the standard serial-dilution method. Regression analysis was used to determine a standard curve from which an equation was derived that allowed demonstration of the mentioned correlation. The equation was then used to convert the corrected absorbance readings of the single working dilution directly into the predicted ELISA antibody titres. A high level of sensitivity of 96 per cent and specificity of 91 per cent between ELISA and MAT titres was found. The kappa value was almost 1.0 indicating perfect agreement. Interpretation & conclusions: The r LipL32 ELISA was proved to be sensitive, specific and accurate as compared to the standard MAT and the test could be efficiently utilized as a screening test for a large number of human serum samples for the detection of leptospiral antibodies. [ABSTRACT FROM AUTHOR]

Abstract: A recombinant haemagglutinin neuraminidase (HN) antigen-based single serum dilution enzyme linked immuno-sorbent assay (ELISA) was developed to measure the specific antibody in sera of chickens against Newcastle disease virus. A linear relationship was found between the predicted antibody titres at a single working dilution of 1:1000 and the corresponding observed serum titres as determined by the standard serial dilution method. Regression analysis was used to determine a standard curve from which an equation was derived that allowed the demonstration of this correlation. The equation was then used to convert the corrected absorbance readings of the single working dilution directly into the predicted ELISA antibody titres. The assay proved to be sensitive, specific and accurate as compared to the standard haemagglutination inhibition (HI) test. [Copyright &y& Elsevier]

A recombinant antigen-based single serum dilution enzyme-linked immunosorbent assay (ELISA) was developed to measure the specific antibody activity in sera of dogs with leptospirosis. The recombinant antigen developed and used in the assay was specific for the pathogenic serovars of Leptospira. A linear relationship was found to exist between the predicted antibody titres at a single working dilution of 1:1000 and the corresponding observed serum titres as determined by the standard serial-dilution method. Regression analysis was used to determine a standard curve from which an equation can be derived that allows demonstration of the mentioned correlation. The equation was then used to convert the corrected absorbance readings of the single working dilution directly into the predicted ELISA antibody titres. The assay was proved to be sensitive, specific and accurate as compared to the standard microscopic agglutination test (MAT). [Copyright &y& Elsevier]

Abstract: A recombinant UL30 antigen-based single serum dilution enzyme linked immunosorbent assay (ELISA) was developed to measure specific antibody in the sera of ducks against duck enteritis virus (DEV). The partial UL30 gene of DEV was cloned, expressed, purified and tested for its diagnostic use by designing a single serum dilution enzyme linked immuno-sorbent assay (ELISA). A total of 226 duck sera samples were tested using the assay. A linear relationship was found between the predicted antibody titres at a single working dilution of 1:100 and the corresponding serum titres observed as determined by the standard serial dilution method. Regression analysis was used to determine a standard curve from which an equation was derived which demonstrated this correlation. The equation was then used to convert the corrected absorbance readings of the single working dilution directly into the predicted ELISA antibody titres. The assay proved to be specific, sensitive and accurate as compared to the virus neutralization test with a specificity, sensitivity and accuracy being 96%, 95% and 95% respectively. [Copyright &y& Elsevier]