Volume 32, Number 8—August 2026
Research
Detection of Highly Pathogenic Avian Influenza A(H5N1) Clade 2.3.4.4b Genotype D1.2 Virus in Swine after Experimental Inoculation
Hannah Seger, Amy L. Baker, Alexandra C. Buckley, Tavis K. Anderson, Alexey Markin, Alessandra Campos, Bruno Caetano Trindade, Marissa Vincent, Giovana Ciacci Zanella, Mia Torchetti, Kristina Lantz, and Bailey Arruda
Table 1
Nasal swab specimen Ct values for pigs in study of systemic distribution and protracted detection of highly pathogenic avian influenza A(H5N1) clade 2.3.4.4b genotype D1.2 virus in swine after experimental inoculation*
| Group and pig ID | DPI |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 14 | 35 | |
| D1.2/OR, necropsy at 5 DPI | ||||||||||
| 641 | 40.0 | 33.1 | 25.6 | 29.9 | 32.6 | 23.6 | – | – | – | – |
| 642 | 40.0 | 30.7 | 22.1 | 29.1 | 32.3 | 34.6 | – | – | – | – |
| 643 | 40.0 | 35.3 | 29.4 | 37.0 | 40.0 | 40.0 | – | – | – | – |
| 644 | 40.0 | 32.5 | 31.0 | 39.8 | 40.0 | 38.8 | – | – | – | – |
| 645 | 40.0 | 25.0 | 26.6 | 30.7 | 29.1 | 27.9 | – | – | – | – |
| 646 | 40.0 | 34.3 | 34.6 | 37.0 | 38.3 | 40.0 | – | – | – | – |
| 647 | 40.0 | 28.9 | 25.2 | 31.1 | 34.4 | 34.7 | – | – | – | – |
| 648 |
40.0 |
28.0 |
26.2 |
29.0 |
32.8 |
28.1 |
– |
– |
– |
– |
| D1.2/OR, necropsy at 35 DPI | ||||||||||
| 649 | 40.0 | 24.8 | 19.6 | 26.9 | 31.0 | 34.8 | 36.5 | 35.1 | 39.8 | 40.0 |
| 650 | 40.0 | 32.4 | 26.8 | 32.7 | 33.3 | 36.1 | 36.5 | 36.6 | 40.0 | 40.0 |
| 651 |
40.0 |
28.5 |
26.9 |
31.3 |
32.7 |
35.3 |
36.9 |
38.1 |
40.0 |
40.0 |
| Control, necropsy at 5 DPI | ||||||||||
| 652 | 40.0 | 40.0 | 40.0 | 40.0 | 40.0 | 40.0 | – | – | – | – |
| 653 | 40.0 | 40.0 | 40.0 | 40.0 | 40.0 | 40.0 | – | – | – | – |
| 654 | 40.0 | 40.0 | 40.0 | 40.0 | 40.0 | 40.0 | – | – | – | – |
*Animals were humanely euthanized at 5 or 35 DPI. Samples were tested by quantitative reverse transcription PCR. Light gray shading indicates samples with positive results (Ct <38.0); dark gray shading indicates a suspected result (Ct 38.0–40.0). Samples with a Ct value <35 were selected for virus isolation; bold indicates samples from which virus was isolated. Dashes (–) indicate no sample was taken because the animal had been euthanized. Ct, cycle threshold; DPI, days postinoculation.
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Page updated: July 27, 2026
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