#Influenza D Virus of New Phylogenetic #Lineage, #Japan (Emerg Infect Dis., abstract)

[Source: US Centers for Disease Control and Prevention (CDC), Emerging Infectious Diseases Journal, full page: (LINK). Abstract, edited.]

Volume 26, Number 1—January 2020 / Research Letter

Influenza D Virus of New Phylogenetic Lineage, Japan

Shin Murakami, Ryota Sato, Hiroho Ishida, Misa Katayama, Akiko Takenaka-Uema, and Taisuke Horimoto

Author affiliations: University of Tokyo, Tokyo, Japan (S. Murakami, H. Ishida, M. Katayama, A. Takenaka-Uema, T. Horimoto); Yamagata Livestock Hygiene Service Center, Yamagata, Japan (R. Sato)



Influenza D virus (IDV) can potentially cause respiratory diseases in livestock. We isolated a new Japan IDV strain from diseased cattle; this strain is phylogenetically and antigenically distinguished from the previously described IDVs.

Keywords: Influenza D; Cattle; Japan.


Expression of 9-O- and 7,9-O-Acetyl Modified #Sialic Acid in Cells and Their Effects on #Influenza Viruses (MBio, abstract)

[Source: MBio, full page: (LINK). Abstract, edited.]

Expression of 9-O- and 7,9-O-Acetyl Modified Sialic Acid in Cells and Their Effects on Influenza Viruses

Karen N. Barnard, Brian R. Wasik, Justin R. LaClair, David W. Buchholz, Wendy S. Weichert, Brynn K. Alford-Lawrence, Hector C. Aguilar, Colin R. Parrish

Xiang-Jin Meng, Editor

DOI: 10.1128/mBio.02490-19



Sialic acids (Sia) are widely displayed on the surfaces of cells and tissues. Sia come in a variety of chemically modified forms, including those with acetyl modifications at the C-7, C-8, and C-9 positions. Here, we analyzed the distribution and amounts of these acetyl modifications in different human and canine cells. Since Sia or their variant forms are receptors for influenza A, B, C, and D viruses, we examined the effects of these modifications on virus infections. We confirmed that 9-O-acetyl and 7,9-O-acetyl modified Sia are widely but variably expressed across cell lines from both humans and canines. Although they were expressed on the cell surfaces of canine MDCK cell lines, they were located primarily within the Golgi compartment of human HEK-293 and A549 cells. The O-acetyl modified Sia were expressed at low levels of 1 to 2% of total Sia in these cell lines. We knocked out and overexpressed the sialate O-acetyltransferase gene (CasD1) and knocked out the sialate O-acetylesterase gene (SIAE) using CRISPR/Cas9 editing. Knocking out CasD1 removed 7,9-O- and 9-O-acetyl Sia expression, confirming previous reports. However, overexpression of CasD1 and knockout of SIAE gave only modest increases in 9-O-acetyl levels in cells and no change in 7,9-O-acetyl levels, indicating that there are complex regulations of these modifications. These modifications were essential for influenza C and D infection but had no obvious effect on influenza A and B infection.



Sialic acids are key glycans that are involved in many different normal cellular functions, as well as being receptors for many pathogens. However, Sia come in diverse chemically modified forms. Here, we examined and manipulated the expression of 7,9-O- and 9-O-acetyl modified Sia on cells commonly used in influenza virus and other research by engineering the enzymes that produce or remove the acetyl groups.

Keywords: Influenza A; Influenza B; Influenza C; Influenza D; Viral pathogenesis.


A murine #model for the study of #influenza D virus (J Virol., abstract)

[Source: Journal of Virology, full page: (LINK). Abstract, edited.]

A murine model for the study of influenza D virus.

J Oliva, J Mettier, L Sedano, M Delverdier, N Bourgès-Abella, B. Hause, J Loupias, I. Pardo, C. Bleuart, P. J.. Bordignon, E Meunier, R Le Goffic, G Meyer, M. F. Ducatez

DOI: 10.1128/JVI.01662-19



A novel genus within the Orthomyxoviridae family was identified in the USA and named Influenza D virus (IDV). Bovine have been proposed to be the primary host and three main viral lineages (D/OK-like, D/660-like and D/Japan-like) have been described. Experimental infections were so far performed in swine, ferret, calf and guinea pig, in order to study IDV pathogenesis.

We developed a murine experimental model to ease the study of IDV pathogenesis and immune response. DBA/2 mice were inoculated with 105 TCID50 of D/bovine/France/5920/2014 (D/OK-like). No clinical signs and weight loss were observed. Viral replication was observed mainly in the upper respiratory tract (nasal turbinates) but also in lower respiratory tract of infected mice, with a peak at 4 days post-infection. Moreover, the virus was also detected in the intestines. All infected mice seroconverted by 14 days post infection. Transcriptomic analyses demonstrated that IDV induced an activation of pro-inflammatory genes such as IFN-γ and CCL2. Inoculation of NFκB-luciferase and Ifnar1-/- mice demonstrated that IDV induced mild inflammation and that type I interferons response was not necessary in IDV clearance. Adaptation of IDV by serial passages in mice was not sufficient to induce disease or increased pathogenesis.

Taken together, present data and comparisons with the calf model show that our mouse model allows for the study of IDV replication and fitness (before selected viruses may be inoculated on calves) and also of the immune response.



Influenza D virus (IDV), a new genus of Orthomyxoviridae family, presents a large host range and a worldwide circulation. The pathogenicity of this virus has been studied in the calf model. The mouse model is frequently used to enable a first assessment of a pathogen’s fitness, replication and pathogenesis for influenza A and B viruses. We showed that DBA/2 mice are a relevant in vivo model for the study of IDV replication. This model will allow for rapid IDV fitness and replication evaluation and will enable phenotypic comparisons between isolated viruses. It will also allow for a better understanding of the immune response induced after IDV infection.

Copyright © 2019 American Society for Microbiology. All Rights Reserved.

Keywords: Influenza D; Cattle; Animal models.


#Serosurvey for #Influenza D Virus Exposure in #Cattle, #USA, 2014–2015 (Emerg Infect Dis., abstract)

[Source: US Centers for Disease Control and Prevention (CDC), Emerging Diseases Journal, full page: (LINK). Abstract, edited.]

Volume 25, Number 11—November 2019 / Research

Serosurvey for Influenza D Virus Exposure in Cattle, United States, 2014–2015

Simone Silveira, Shollie M. Falkenberg  , Bryan S. Kaplan, Beate Crossley, Julia F. Ridpath, Fernando B. Bauermann, Charles P. Fossler, David A. Dargatz, Rohana P. Dassanayake, Amy L. Vincent, Cláudio W. Canal, and John D. Neill

Author affiliations: Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil (S. Silveira, C.W. Canal); US Department of Agriculture, Ames, Iowa, USA (S.M. Falkenberg, B.S. Kaplan, J.F. Ridpath, R.P. Dassanayake, A.L. Vincent, J.D. Neill); University of California, Davis, California, USA (B. Crossley); Oklahoma State University, Stillwater, Oklahoma, USA (F.B. Bauermann); US Department of Agriculture, Fort Collins, Colorado, USA (C.P. Fossler, D.A. Dargatz)



Influenza D virus has been detected predominantly in cattle from several countries. In the United States, regional and state seropositive rates for influenza D have previously been reported, but little information exists to evaluate national seroprevalence. We performed a serosurveillance study with 1,992 bovine serum samples collected across the country in 2014 and 2015. We found a high overall seropositive rate of 77.5% nationally; regional rates varied from 47.7%–84.6%. Samples from the Upper Midwest and Mountain West regions showed the highest seropositive rates. In addition, seropositive samples were found in 41 of the 42 states from which cattle originated, demonstrating that influenza D virus circulated widely in cattle during this period. The distribution of influenza D virus in cattle from the United States highlights the need for greater understanding about pathogenesis, epidemiology, and the implications for animal health.

Keywords: Influenza D; Cattle; Seroprevalence; USA.


#Development and characterization of a #reverse #genetics system for #influenza D virus (J Virol., abstract)

[Source: Journal of Virology, full page: (LINK). Abstract, edited.]

Development and characterization of a reverse genetics system for influenza D virus

Jieshi Yu, Runxia Liu, Bin Zhou, Tsui-wen Chou, Elodie Ghedin, Zizhang Sheng, Rongyuan Gao, Shao-lun Zhai, Dan Wang, Feng Li

DOI: 10.1128/JVI.01186-19



Influenza D virus (IDV) of the Orthomyxoviridae family has a wide host range and a broad geographical distribution. Recent IDV outbreaks in swine, along with serological and genetic evidence of IDV infection in humans have raised concerns regarding the zoonotic potential of this virus. To better study IDV at the molecular level, a reverse genetics system (RGS) is urgently needed, but to date no RGS had been described for IDV. In this study, we rescued the recombinant influenza D/swine/Oklahoma/1314/2011 (D/OK) virus by using a bidirectional seven plasmid-based system, and further characterized rescued viruses in terms of growth kinetics, replication stability, and receptor-binding capacity. Our results collectively demonstrated that RGS-derived viruses resembled the parental viruses for these properties, thereby supporting the utility of this RGS to study IDV infection biology. In addition, we developed an IDV mini-genome replication assay and identified the E697K mutation in PB1 and the L462F mutation in PB2 that directly affected the activity of the IDV ribonucleoprotein complex (RNP), resulting in either attenuated or replication-incompetent viruses. Finally, by using the mini-genome replication assay, we demonstrated that a single nucleotide polymorphism at position 5 of the 3′ conserved noncoding region in IDV and ICV resulted in the inefficient cross-recognition of the heterotypic promoter by the viral RNP complex. In conclusion, we successfully developed a mini-genome replication assay and a robust reverse genetics system that can be used to further study replication, tropism, and pathogenesis of IDV.



Influenza D virus (IDV) is a new type of influenza virus that uses cattle as the primary reservoir and infects multiple agricultural animals. Increased outbreaks in pigs, and serological and genetic evidence of human infection have raised concerns about potential IDV adaptation in humans. Here, we have developed a plasmid-based IDV reverse genetics system that can generate infectious viruses similar in replication kinetics to wild-type viruses following transfection of cultured cells. Further characterization demonstrated that viruses rescued from the described RGS resembled the parental viruses in biological and receptor binding properties. We also developed and validated an IDV minireplicon reporter system that specifically measures viral RNA polymerase activity. In summary, the reverse genetics system and minireplicon reporter assay as described in this study should be of value in identifying viral determinants of cross-species transmission and pathogenicity of novel influenza D viruses.

Copyright © 2019 American Society for Microbiology. All Rights Reserved.

Keywords: Influenza D.


Susceptibility of #Influenza A, B, C, and D Viruses to #Baloxavir (Emerg Infect Dis., abstract)

[Source: US Centers for Disease Control and Prevention (CDC), Emerging Infectious Diseases Journal, full page: (LINK). Abstract, edited.]

Volume 25, Number 10—October 2019 / Dispatch

Susceptibility of Influenza A, B, C, and D Viruses to Baloxavir

Vasiliy P. Mishin, Mira C. Patel, Anton Chesnokov, Juan De La Cruz, Ha T. Nguyen, Lori Lollis, Erin Hodges, Yunho Jang, John Barnes, Timothy Uyeki, Charles T. Davis, David E. Wentworth, and Larisa V. Gubareva

Author affiliations: Centers for Disease Control and Prevention, Atlanta, Georgia, USA (V.P. Mishin, M.C. Patel, A. Chesnokov, J. De La Cruz, H.T. Nguyen, L. Lollis, E. Hodges, Y. Jang, J. Barnes, T. Uyeki, C.T. Davis, D.E. Wentworth, L.V. Gubareva); Battelle Memorial Institute, Atlanta (M.C. Patel, J. De La Cruz, H.T. Nguyen, L. Lollis)



Baloxavir showed broad-spectrum in vitro replication inhibition of 4 types of influenza viruses (90% effective concentration range 1.2–98.3 nmol/L); susceptibility pattern was influenza A ˃ B ˃ C ˃ D. This drug also inhibited influenza A viruses of avian and swine origin, including viruses that have pandemic potential and those resistant to neuraminidase inhibitors.

Keywords: Antivirals; Drugs Resistance; Oseltamivir; Favipiravir; Baloxavir; Influenza A; Influenza B; Influenza C; Influenza D; H1N1pdm09; H3N2; H7N9.


#Influenza A in #Bovine Species: A Narrative Literature Review (Viruses, abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Viruses. 2019 Jun 17;11(6). pii: E561. doi: 10.3390/v11060561.

Influenza A in Bovine Species: A Narrative Literature Review.

Sreenivasan CC1, Thomas M2, Kaushik RS3, Wang D4,5, Li F6,7.

Author information: 1 Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA. chithra.sreenivasan@sdstate.edu. 2 Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, SD 57007, USA. milton.thomas@sdstate.edu. 3 Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA. radhey.kaushik@sdstate.edu. 4 Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA. dan.wang@sdstate.edu. 5 BioSystems Networks and Translational Research Center (BioSNTR), Brookings, SD 57007, USA. dan.wang@sdstate.edu. 6 Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA. feng.li@sdstate.edu. 7 BioSystems Networks and Translational Research Center (BioSNTR), Brookings, SD 57007, USA. feng.li@sdstate.edu.



It is quite intriguing that bovines were largely unaffected by influenza A, even though most of the domesticated and wild animals/birds at the human-animal interface succumbed to infection over the past few decades. Influenza A occurs on a very infrequent basis in bovine species and hence bovines were not considered to be susceptible hosts for influenza until the emergence of influenza D. This review describes a multifaceted chronological review of literature on influenza in cattle which comprises mainly of the natural infections/outbreaks, experimental studies, and pathological and seroepidemiological aspects of influenza A that have occurred in the past. The review also sheds light on the bovine models used in vitro and in vivo for influenza-related studies over recent years. Despite a few natural cases in the mid-twentieth century and seroprevalence of human, swine, and avian influenza viruses in bovines, the evolution and host adaptation of influenza A virus (IAV) in this species suffered a serious hindrance until the novel influenza D virus (IDV) emerged recently in cattle across the world. Supposedly, certain bovine host factors, particularly some serum components and secretory proteins, were reported to have anti-influenza properties, which could be an attributing factor for the resilient nature of bovines to IAV. Further studies are needed to identify the host-specific factors contributing to the differential pathogenetic mechanisms and disease progression of IAV in bovines compared to other susceptible mammalian hosts.

KEYWORDS: Influenza A; MDBK cells; bovine; bovine cell cultures; bovine respiratory disease; bronchopneumonia; cattle outbreaks; epizootic cough; host restriction; ruminants; seroprevalence

PMID: 31213032 DOI: 10.3390/v11060561

Keywords: Influenza A; Influenza D; Bovine.