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Volume 24, Number 1—January 2018

Mammalian Pathogenesis and Transmission of Avian Influenza A(H7N9) Viruses, Tennessee, USA, 2017

Jessica A. Belser, Nicole Brock, Xiangjie Sun, Joyce Jones, Natosha Zanders, Erin Hodges, Joanna A. Pulit-Penaloza, David Wentworth, Terrence M. Tumpey, Todd Davis, and Taronna R. MainesComments to Author 
Author affiliations: Centers for Disease Control and Prevention, Atlanta, Georgia, USA

Main Article


Infection of mice and ferrets with influenza A(H7N9) ck/TN viruses, Tennessee, USA, 2017*

Characteristic LPAI HPAI
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
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.

Main Article

Page created: December 19, 2017
Page updated: December 19, 2017
Page reviewed: December 19, 2017
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.