Volume 28, Number 9—September 2022
Research Letter
Pathogenesis and Transmissibility of North American Highly Pathogenic Avian Influenza A(H5N1) Virus in Ferrets
Table
Results of ferrets inoculated with influenza A(H5N1) virus isolate A/American Wigeon/SC/22–000345–001/2021*
| Parameter | Value |
|---|---|
| Weight loss, %† |
4.7 |
| Temperature increase, °C‡ |
1.1 |
| Nasal wash titer (peak titer days)§ |
4.6 (1–5) |
| Virus titer at day 3 postinoculation¶ | |
| Nasal wash | 2.4 (3/3) |
| Nasal turbinates | 3.5 (3/3) |
| Soft palate | 2.9 (3/3) |
| Trachea | ND |
| Lung | 2.2 (1/3) |
*Six ferrets were inoculated with 6 log10 EID50 of A/American Wigeon/SC/22-000345-001/2021 (GISAID identical virus sequence accession no. EPI_ISL_9869760, https://www.gisaid.org; in a 1-mL volume. Three additional ferrets were inoculated and then euthanized and tested for virus titer at day 3 postinoculation. EID50, 50% egg infectious dose; ND, not detected †Percentage mean maximum weight loss within 9 days postinoculation. ‡Mean maximum rise in body temperature from baseline (37.6°C–39.4°C). §Mean maximum virus titer in nasal washes, expressed as log10 EID50/mL. ¶Viral titers are expressed as log10 EID50/mL, except for lung titer, which is expressed as log10 EID50/g of tissue. Number of ferrets with detectable virus is specified in parentheses. Limit of virus detection was 1.5 log10 EID50/mL or g.