scholarly journals A STUDY IN VITRO OF COMPONENTS IN THE TRANSMISSION CYCLE OF SWINE INFLUENZA VIRUS

1961 ◽  
Vol 114 (6) ◽  
pp. 1023-1033 ◽  
Author(s):  
W. D. Peterson ◽  
Fred M. Davenport ◽  
Thomas Francis
Keyword(s):  
Influenza Virus ◽  
Infectious Virus ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
Influenza Virus A ◽  
Transmission Cycle

Swine lungworm extracts and suspensions of swine lungworms contain receptor-like substances capable of adsorbing influenza virus, a result consonant with the hypothesis (5–8) that the lungworm may be involved in the swine influenza cycle. Yet no evidence for multiplication of virus or even persistence of infectious virus in lungworms at undimished titer was found. Clearly much more information is needed, and it is hoped that the present demonstration of the practicality of studying the components of the transmission cycle proposed by Shope, will provide important tools requisite for further investigation of this problem. Studies on the role of the earthworm in the transmission of swine influenza suggest that, at best, that role would be a passive one.

scholarly journals Mutations in the NS1 Protein of Swine Influenza Virus Impair Anti-Interferon Activity and Confer Attenuation in Pigs

2005 ◽  
Vol 79 (12) ◽  
pp. 7535-7543 ◽  
Author(s):  
Alicia Solórzano ◽  
Richard J. Webby ◽  
Kelly M. Lager ◽  
Bruce H. Janke ◽  
Adolfo García-Sastre ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Nonstructural Protein ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
Influenza Viruses ◽  
Model Systems ◽  
Ns1 Protein ◽  
Wild Type ◽  
Virulence Attenuation

ABSTRACT It has been shown previously that the nonstructural protein NS1 of influenza virus is an alpha/beta interferon (IFN-α/β) antagonist, both in vitro and in experimental animal model systems. However, evidence of this function in a natural host has not yet been obtained. Here we investigated the role of the NS1 protein in the virulence of a swine influenza virus (SIV) isolate in pigs by using reverse genetics. The virulent wild-type A/Swine/Texas/4199-2/98 (TX/98) virus and various mutants encoding carboxy-truncated NS1 proteins were rescued. Growth properties of TX/98 viruses with mutated NS1, induction of IFN in tissue culture, and virulence-attenuation in pigs were analyzed and compared to those of the recombinant wild-type TX/98 virus. Our results indicate that deletions in the NS1 protein decrease the ability of the TX/98 virus to prevent IFN-α/β synthesis in pig cells. Moreover, all NS1 mutant viruses were attenuated in pigs, and this correlated with the amount of IFN-α/β induced in vitro. These data suggest that the NS1 protein of SIV is a virulence factor. Due to their attenuation, NS1-mutated swine influenza viruses might have a great potential as live attenuated vaccine candidates against SIV infections of pigs.

Role of IFN-α during the acute stage of a swine influenza virus infection

2010 ◽  
Vol 88 (1) ◽  
pp. 172-178 ◽  
Author(s):  
Filip Barbé ◽  
Xavier Saelens ◽  
Debby Braeckmans ◽  
François Lefèvre ◽  
Kristien Van Reeth
Keyword(s):  
Influenza Virus ◽  
Virus Infection ◽  
Swine Influenza Virus ◽  
Influenza Virus Infection ◽  
Swine Influenza ◽  
Acute Stage

scholarly journals IFI27 transcription is an early predictor for COVID-19 outcomes; a multi-cohort observational study

2021 ◽  
Author(s):  
Maryam Shojaei ◽  
Amir Shamshirian ◽  
James Monkman ◽  
Laura Grice ◽  
Minh Tran ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Observational Study ◽  
Swine Influenza Virus ◽  
Influenza Virus Infection ◽  
Swine Influenza ◽  
High Viral Load ◽  
Diagnostic Tools ◽  
The Family ◽  
Inducible Protein

Background. Robust biomarkers that predict disease outcomes amongst COVID19 patients are necessary for both patient triage and resource prioritisation. Numerous candidate biomarkers have been proposed for COVID19. However, at present, there is no consensus on the best diagnostic approach to predict outcomes in infected patients. Moreover, it is not clear whether such tools would apply to other potentially pandemic pathogens and therefore of use as stockpile for future pandemic preparedness. Methods. We conducted a multi cohort observational study to investigate the biology and the prognostic role of interferon alpha inducible protein 27 (IFI27) in COVID19 patients. Findings. We show that IFI27 is expressed in the respiratory tract of COVID19 patients and elevated IFI27 expression is associated with the presence of a high viral load. We further demonstrate that systemic host response, as measured by blood IFI27 expression, is associated with COVID19 severity. For clinical outcome prediction (e.g. respiratory failure), IFI27 expression displays a high positive (0.83) and negative (0.95) predictive value, outperforming all other known predictors of COVID19 severity. Furthermore, IFI27 is upregulated in the blood of infected patients in response to other respiratory viruses. For example, in the pandemic H1N1/09 swine influenza virus infection, IFI27 like genes were highly upregulated in the blood samples of severely infected patients. Interpretation. These data suggest that prognostic biomarkers targeting the family of IFI27 genes could potentially supplement conventional diagnostic tools in future virus pandemics, independent of whether such pandemics are caused by a coronavirus, an influenza virus or another as yet to be discovered respiratory virus.

scholarly journals The Role of Gilts in Transmission Dynamics of Swine Influenza Virus and Impacts of Vaccination Strategies and Quarantine Management

2021 ◽  
Author(s):  
Pia Ryt-Hansen ◽  
Henriette Guldberg Nielsen ◽  
Simon Smed Sørensen ◽  
Inge Larsen ◽  
Charlotte Sonne Kristensen ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
Vaccination Strategy ◽  
Cross Sectional Study ◽  
Control Measures ◽  
Transmission Dynamics ◽  
Cross Sectional ◽  
The Impact

Abstract Along with an expanding global swine production, the commercial housing and management of swine herds, provide an optimal environment for constant circulation of swine influenza virus (swIAV), thereby challenging farmers and veterinarian in determining optimal control measures. The aim of this study was to investigate the role of gilts in the swIAV transmission dynamics, and to evaluate the impact of different control measures such as quarantine and gilt vaccination. The study was conducted as a cross-sectional study in ten Danish sow herds, including five swIAV vaccinated and five unvaccinated herds. Blood- and nasal swab samples of gilts, first parity sows, and piglets were collected in different stable units of the production system and analyzed for the presence of swIAV and swIAV antibodies. Associations between the detection of swIAV, seroprevalence, antibody levels, quarantine measures and vaccination strategy were thereafter investigated to identify possible risk factors for swIAV introductions and persistence within the herds.Nine of the ten herds had gilts or litters of first parity sows testing positive for swIAV, and swIAV was detected in both the quarantine, mating- and farrowing unit. The seroprevalence were generally higher in the vaccinated herds, but swIAV was still present in nasal swabs from both gilts and piglets in these herds. Notably, the results revealed that having positive gilts in the end of the quarantine increased the risk of having positive one-week-old litters in the farrowing unit by 2.5 times. These results underline that gilts are important contributors to the continuous circulation of swIAV. Additionally, the recorded vaccination schedules along with quarantine and biosecurity measures were far from optimal emphasizing a needed focus on these factors if control of pathogens such as swIAV is desired.

scholarly journals PB1-F2 Protein Does Not Impact the Virulence of Triple-Reassortant H3N2 Swine Influenza Virus in Pigs but Alters Pathogenicity and Transmission in Turkeys

2015 ◽  
Vol 90 (1) ◽  
pp. 222-231 ◽  
Author(s):  
Jagadeeswaran Deventhiran ◽  
Sandeep R. P. Kumar ◽  
Shobana Raghunath ◽  
Tanya Leroith ◽  
Subbiah Elankumaran
Keyword(s):  
Influenza Virus ◽  
Swine Influenza Virus ◽  
Clinical Signs ◽  
Influenza Virus Infection ◽  
Swine Influenza ◽  
The Other ◽  
Mammalian Host ◽  
Lung Pathology ◽  
Other Hand

ABSTRACTPB1-F2 protein, the 11th influenza A virus (IAV) protein, is considered to play an important role in primary influenza virus infection and postinfluenza secondary bacterial pneumonia in mice. The functional role of PB1-F2 has been reported to be a strain-specific and host-specific phenomenon. Its precise contribution to the pathogenicity and transmission of influenza virus in mammalian host, such as swine, and avian hosts, such as turkeys, remain largely unknown. In this study, we explored the role of PB1-F2 protein of triple-reassortant (TR) H3N2 swine influenza virus (SIV) in pigs and turkeys. Using the eight-plasmid reverse genetics system, we rescued wild-type SIV A/swine/Minnesota/1145/2007 (H3N2) (SIV 1145-WT), a PB1-F2 knockout mutant (SIV 1145-KO), and its N66S variant (SIV 1145-N66S). The ablation of PB1-F2 in SIV 1145 modulated early-stage apoptosis but did not affect the viral replication in swine alveolar macrophage cells. In pigs, PB1-F2 expression did not affect nasal shedding, lung viral load, immunophenotypes, and lung pathology. On the other hand, in turkeys, SIV 1145-KO infected poults, and its in-contacts developed clinical signs earlier than SIV 1145-WT groups and also displayed more extensive histopathological changes in intestine. Further, turkeys infected with SIV 1145-N66S displayed poor infectivity and transmissibility. The more extensive histopathologic changes in intestine and relative transmission advantage observed in turkeys infected with SIV 1145-KO need to be further explored. Taken together, these results emphasize the host-specific roles of PB1-F2 in the pathogenicity and transmission of IAV.IMPORTANCENovel triple-reassortant H3N2 swine influenza virus emerged in 1998 and spread rapidly among the North American swine population. Subsequently, it showed an increased propensity to reassort, generating a range of reassortants. Unlike classical swine influenza virus, TR SIV produces a full-length PB1-F2 protein, which is considered an important virulence marker of IAV pathogenicity. Our study demonstrated that the expression of PB1-F2 does not impact the pathogenicity of TR H3N2 SIV in pigs. On the other hand, deletion of PB1-F2 caused TR H3N2 SIV to induce clinical disease early and resulted in effective transmission among the turkey poults. Our study emphasizes the continuing need to better understand the virulence determinants for IAV in intermediate hosts, such as swine and turkeys, and highlights the host-specific role of PB1-F2 protein.

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