Antigenic characterization of type B influenza viruses, by
hemagglutination inhibitation
total samplest (% seropositive samples, 95% CI) Post-third wave HI MN Age group, y < 5 99/160 (0.62, 93/150 (0.62, 0.54-0.69) 0.54-0.7) 5-14 155/200 (0.78, 146/199 (0.73, 0.71-0.83) 0.67-0.79) 15-24 216/320 (0.68, 188/311 (0.6, 0.62-0.73) 0.55-0.66) 25-44 187/294 (0.64, 155/283 (0.55, 0.58-0.69) 0.49-0.61) 45-64 62/138 (0.45, 52/135 (0.39, 0.36-0.54) 0.3-0.47) 65-74 38/74 (0.51, 38/74 (0.51, 0.39-0.63) 0.39-0.63) [greater than 46/71 (0.65, 39/71 (0.55, or equal 0.53-0.76) 0.43-0.67) to] 75 Region ([section]) Total 1,202 1,782 1,257 North West 561 624 337 South West 404 232 265 North East 237 526 179 East 0 292 122 Yorkshire and 0 108 354 Humber * HI,
hemagglutination inhibition assay; MN, microneutralization assay.
(*)A case is considered serologically confirmed if testing reveals an indirect fluorescent antibody (IFA) titer of [is greater than or equal to] 1:64, a complement-fixation (CF) titer of [is greater than or equal to] 1:16, or a fourfold rise in titer by the CF, IFA, microgglunatination (MA), latex agglutination (LA), or indirect
hemagglutination (IHA) assays.
Samples with a
hemagglutination inhibition value [greater than or equal to]1:10 were considered positive.
As recommended by WHO, samples that were antibody-positive by MN underwent confirmatory testing by
hemagglutination inhibition assay with horse erythrocytes or by H5-specific Western blot analysis (9,10).
Virus isolation was assessed by
hemagglutination inhibition (HI) assay and neuraminidase inhibition assay by using a panel of reference serum samples (National Reference Laboratory for Avian Influenza, Harbin Veterinary Research Institute, Harbin City, China).
pallidum
hemagglutination assay (TPHA) (Syphagen; Biokit).
pallidum
hemagglutination assay) and nonspecific (Venereal Disease Research Laboratory [VDRL]) test results for Treponema spp.
All samples were delivered to the Kansas State Veterinary Diagnostic Laboratory for analysis by influenza matrix rRT-PCR and virus isolation on nasal swab samples and
hemagglutination inhibition (HI) assays against classical swine influenza virus (H1N1) (A/swine/Iowa/73) and the prototype swine influenza virus (H3N2) (A/swine/Texas/98) on serum samples.
Hemagglutination inhibition antibody titers and virus neutralizing titers were highly elevated above background levels for ZIKV and yellow fever virus (YFV) compared with other viruses tested.
To detect influenza D infection, we titrated the serum samples by
hemagglutination inhibition (HI) assay using 3 antigenically distinct influenza D strains: D/swine/0klahoma/1334/2011 (D-OK lineage; D/OK) (1), D/bovine/Nebraska/9-5/2013 (D/660-lineage; D/NE) (6), and D/bovine/Yamagata/10710/2016 (D/Japan-lineage; D/Yamagata) (7).