Table 2. Hemagglutinin inhibition assay titers using 2-fold serial dilutions of virus-specific antiserum in study of highly pathogenic avian influenza A(H5N1) virus clade 2.3.4.4b in domestic ducks, Indonesia, 2022*.
| Antiserum source, clade, GISAID no.† | Antigen source |
|||
|---|---|---|---|---|
| A/duck/Hulu Sungai Utara/A0522064-06/2022 | A/duck/Hulu Sungai Utara/A0522064-03-04/2022 | A/duck/Hulu Sungai Utara/A0522067-06-07/2022 | A/muscovy duck/ Banjarbaru/A0523532-9/2023 | |
| A/chicken/West Java/PWT-WIJ/2006, H5N1 clade 2.1.3.2, EPI_ISL_12700530‡ |
<4 |
<4 |
<4 |
16 |
| A/chicken/Barru/BBVM 41-13/2013, H5N1 clade 2.1.3.2a, EPI_ISL_17767706 |
16 |
16 |
16 |
16 |
| A /duck/Sukoharjo/BBVW-1428-9/2012, H5N1 clade 2.3.2.1c, EPI_ISL_266808§ |
16 |
32 |
32 |
32 |
| A/chicken/Tanggamus/031711076-65/2017, H5N1 clade 2.3.2.1c, EPI_ISL_17767763¶ |
16 |
32 |
16 |
32 |
| A/duck/Laos/XBY004/2014, H5N6 clade 2.3.4.4b, EPI_ISL_168385 |
8 |
16 |
8 |
16 |
| A/duck/Hulu Sungai Utara/A0522064-03-04/2022, H5N1 clade 2.3.4.4b# | 512 | 512 | 128 | 128 |
*Viruses were isolated by using the World Organisation for Animal Health protocol (7). The 3 viruses isolated from Hulu Sungai Utara in April 2022 and the virus isolated from Banjarbaru in July 2023 were used as antigen sources. †GISAID (https://www.gisaid.org). ‡H5N1 clade 2.1.3.2 vaccine-seed strain used in Indonesia since 2009. §H5N1 clade 2.3.2.1c vaccine strain used during 2012–2020. ¶H5N1 clade 2.3.2.1c vaccine strain used since 2021. #Homologous antiserum for H5N1 clade 2.3.4.4b viruses isolated from the initial outbreak in Hulu Sungai Utara, April 2022.