Volume 24, Number 1—January 2018
Dispatch
Mammalian Pathogenesis and Transmission of Avian Influenza A(H7N9) Viruses, Tennessee, USA, 2017
Table
Infection of mice and ferrets with influenza A(H7N9) ck/TN viruses, Tennessee, USA, 2017*
| Characteristic | LPAI | HPAI |
|---|---|---|
| Mice† | ||
| Weight loss‡ | 1.7 | 2.3 |
| Virus titer§ | ||
| 106 lung, day 3 pi | 4.3 ± 1.1 | <1.5 |
| 103 lung, day 3 pi | 2.8 (1/3) | <1.5 |
| 106 lung, day 6 pi | 5.6 ± 2.1 | <1.5 |
| 103 lung, day 6 pi |
<1.5 |
<1.5 |
| Ferrets, days 1–10 pi¶ | ||
| Weight loss‡ | 3.1 | 4.6 |
| Fever# | 1.2 | 0.6 |
| Virus in rectal swab specimen** | 2/3 | 1/3 |
| Virus titer at day 3 pi§ | ||
| Nasal wash | 4.9 ± 0.5 | 3.6 ± 0.9 |
| Nasal turbinates | 5.8 ± 0.6 | 4.8 ± 0.8 |
| Trachea | 3.5 ± 0.4 (2/3) | <1.5 |
| Lung | <1.5 | <1.5 |
| Olfactory bulb | 3.8 (1/3) | <1.5 |
| Brain | <1.5 | <1.5 |
| Intestine | <1.5 | <1.5 |
*EID50, 50% egg infectious dose; HPAI, highly pathogenic avian influenza virus; LPAI, low pathogenicity avian influenza virus; pi, postinoculation.
†Mice were 8 weeks of age and inoculated intranasally with 106 EID50 or 103 EID50 of virus in a volume of 50 μL.
‡Percent mean maximum weight loss after inoculation with 106 EID50 of virus (days 2–10 pi).
§Virus titers are expressed as mean ± SD log10 EID50/mL for animals with positive virus detection (n = 3 unless otherwise denoted in parentheses). Inoculation dose was 106 EID50 (mice and ferrets) or 103 EID50 (mice). The limit of virus detection was 101.5 EID50/mL.
¶Ferrets were 7 mo of age, serologically negative for currently circulating viruses by hemagglutinin inhibition assay, and inoculated intranasally with 1 mL of virus.
#Mean maximum increase in body temperature (baseline body temperature range 38.1°C–38.9°C).
**No. ferrets with detectable virus in rectal swab specimens collected on days 1, 3, and 5 pi/total no. ferrets tested.