Measurement of antibodies to avian influenza virus A(H7N7) in humans by hemagglutination inhibition test

Section Virology, Diagnostic Laboratory for Infectious Diseases and Screening, National Institute of Public Health and the Environment, PO Box 1, 3720 BA Bilthoven, The Netherlands.
Journal of Virological Methods (Impact Factor: 1.78). 03/2006; 132(1-2):113-20. DOI: 10.1016/j.jviromet.2005.10.001
Source: PubMed


During the epizootic of highly pathogenic avian influenza A(H7N7) in 2003 in The Netherlands, RT-PCR and culture confirmed infection was detected in 89 persons who were ill. A modified hemagglutination inhibition (HI) test using horse erythrocytes and 2 hemagglutinating units of virus was applied to assess retrospectively the extent of human (subclinical) infection. Validation of the HI-test with sera from 34 RT-PCR and culture confirmed A(H7) infected persons and sera from 100 persons from a human influenza vaccine trial in autumn 2002 showed that this HI-test had a sensitivity of 85% and a specificity of 100% when using a cut-off titer of > or =10. Using this cut-off value, A(H7) specific antibodies were detected in 49% of 508 persons exposed to poultry and in 64% of 63 persons exposed to A(H7) infected persons. Correlation of seropositivity with the occurrence of eye symptoms in exposed persons who had not received antiviral prophylaxis and of reduced seropositivity with taking antiviral prophylaxis provided further evidence that the A(H7) HI antibody titers were real. In conclusion, by applying an HI-test using horse erythrocytes human antibodies against the avian A(H7N7) virus were detected with high sensitivity and specificity in an unexpectedly high proportion of exposed persons.


Available from: Adam Meijer
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    • "A. Ahad et al. / Preventive Veterinary Medicine xxx (2014) xxx–xxx 5 of the test (Meijer et al., 2006; Jia et al., 2008; Kayali et al., 2008). Compared with the combined KPK Province and FA, North Punjab presented a lesser risk of infection. "
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    Preventive Veterinary Medicine 10/2014; 117(3-4):610-614. DOI:10.1016/j.prevetmed.2014.10.007 · 2.17 Impact Factor
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    • "Similar to lower antibody responses detected in previous H7 subtype infection in humans [9], the first two available convalescent sera from H7N9 infected individuals only achieved titers of 40 using tRBC HI and titers of 20 and 40 by MN. To improve the H7N9 antibody detection rate, numerous parameters of each serologic assay were modified and examined for heightened sensitivity and specificity against human serum samples collected from H7N9 virus-infected patients. "
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    PLoS ONE 04/2014; 9(4):e95612. DOI:10.1371/journal.pone.0095612 · 3.23 Impact Factor
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    • "Absence of CPE was considered to reflect complete neutralisation (positive reaction). A serum with standard VNT titre at ≥10 was considered to be positive [20,21]. "
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