scholarly journals SEROLOGICAL STUDIES OF SWINE INFLUENZA VIRUSES

1939 ◽  
Vol 69 (6) ◽  
pp. 847-856 ◽  
Author(s):  
Richard E. Shope
Keyword(s):  
Influenza Virus ◽  
Neutralizing Antibodies ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
Influenza Viruses ◽  
Practical Significance ◽  
Homologous Virus ◽  
Heterologous Virus ◽  
Cross Neutralization ◽  
Virus Strains

1. Cross-neutralization tests with sera from swine recovered from infection with swine influenza indicated the serological identity of 7 strains of swine influenza virus obtained from different sources. 2. Cross-neutralization tests with sera from rabbits, immunized to swine influenza virus, exposed serological differences among the same 7 swine influenza virus strains. Two strains appeared to be serologically similar and were characterized by the ability to produce effective homologous virus-neutralizing sera which were, however, poor or ineffective against the heterologous virus strains. Two other strains were also serologically similar but produced antibodies effective not only against themselves, but against all heterologous strains as well. The remaining 3 strains were intermediate in their ability to produce heterologous virus-neutralizing antibodies. 3. The human influenza viruses included, especially strains WS and Oakham, were most effectively differentiated serologically from the swine influenza viruses by rabbit antisera. 4. The suggestion is advanced that swine antisera express the antigenic composition of the swine influenza viruses, while rabbit antisera reflect either their antigenic arrangement or the arrangement of the components responsible for their mouse pathogenicity. On this interpretation the 7 strains of swine influenza virus studied would be considered to have similar antigenic compositions but differing antigenic structures. 5. The serological differences among strains of the swine influenza virus, detectible by rabbit antisera, are probably of no practical significance so far as the natural disease, swine influenza, is concerned.

scholarly journals A single dose vaccination with an elastase-dependent H1N1 live attenuated swine influenza virus protects pigs from challenge with 2009 pandemic H1N1 virus

2014 ◽  
Vol 64 (1) ◽  
pp. 10-23
Author(s):  
Aleksandar Mašić ◽  
Niziti Woldeab ◽  
Carissa Embury-Hyatt ◽  
Yan Zhou ◽  
Shawn Babiuk
Keyword(s):  
Influenza Virus ◽  
Single Dose ◽  
Influenza A Virus ◽  
Neutralizing Antibodies ◽  
Influenza A ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
Influenza Viruses ◽  
Virus Infections ◽  
Intranasal Route

Abstract The 2009 outbreak of H1N1 influenza A viruses in humans underscored the importance of pigs in influenza A virus evolution and the emergence of novel viruses with pandemic potential. In addition, influenza A virus infections continued to cause production losses in the agricultural industry resulting in a significant drop of profit. The primary method to control influenza A virus infections in pigs is through vaccination. Previously we demonstrated that two doses of an elastase-dependent live attenuated swine influenza virus administered by either the intratracheal or intranasal route can provide a high degree of protection in pigs against challenge with both homologous and different heterologous swine influenza viruses. Here we report the protection efficacy of a single dose elastase-dependent live attenuated swine influenza virus administered by the intranasal route against challenge with homologous subtypic H1N1 2009 pandemic swine-like influenza virus. Protection was observed in the absence of neutralizing antibodies specific for H1N1 2009 in sera.

scholarly journals NEUTRALIZATION TESTS WITH SERA OF CONVALESCENT OR IMMUNIZED ANIMALS AND THE VIRUSES OF SWINE AND HUMAN INFLUENZA

1936 ◽  
Vol 63 (5) ◽  
pp. 645-653 ◽  
Author(s):  
Thomas Francis ◽  
Richard E. Shope
Keyword(s):  
Influenza Virus ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
Influenza Viruses ◽  
Human Influenza ◽  
Human Influenza Virus ◽  
Neutralizing Capacity ◽  
Heterologous Virus

Human and swine influenza viruses were regularly neutralized by their homologous immune sera. However, the sera of animals convalescent from infection with either the swine or human influenza virus possessed little, if any, neutralizing capacity for the heterologous virus. Hyperimmunization of animals against swine influenza virus tended to increase the neutralizing capacity of their sera for human influenza virus, but in an inconstant fashion, whereas repeated inoculations with human influenza virus frequently resulted in sera with strong neutralizing activities against swine influenza virus. These observations serve to emphasize both the immunological distinctiveness and the interrelationships of swine and human influenza viruses.

scholarly journals Swine-Origin H1 Influenza Viruses Isolated from Humans Exhibit Sustained Infectivity in an Aerosol State

2019 ◽  
Vol 85 (10) ◽  
Author(s):  
Joanna A. Pulit-Penaloza ◽  
Jessica A. Belser ◽  
Terrence M. Tumpey ◽  
Taronna R. Maines
Keyword(s):  
Influenza Virus ◽  
Swine Influenza Virus ◽  
Virus Transmission ◽  
Swine Influenza ◽  
Influenza Viruses ◽  
Aerosol State ◽  
The Stability ◽  
Higher Doses ◽  
Enhanced Stability

ABSTRACT The relative importance of influenza virus transmission via aerosols is not fully understood, but experimental data suggest that aerosol transmission may represent a critical mode of influenza virus spread among humans. Decades ago, prototypical laboratory strains of influenza were shown to persist in aerosols; however, there is a paucity of data available covering currently circulating influenza viruses, which differ significantly from their predecessors. In this study, we evaluated the longevity of influenza viruses in aerosols generated in the laboratory. We selected a panel of H1 viruses that exhibit diverse transmission profiles in the ferret model, including four human isolates of swine origin (referred to as variant) and a seasonal strain. By measuring the ratio of viral RNA to infectious virus maintained in aerosols over time, we show that influenza viruses known to transmit efficiently through the air display enhanced stability in an aerosol state for prolonged periods compared to those viruses that do not transmit as efficiently. We then assessed whether H1 influenza virus was still capable of infecting and causing disease in ferrets after being aged in suspended aerosols. Ferrets exposed to very low levels of influenza virus (≤17 PFU) in aerosols aged for 15 or 30 min became infected, with five of six ferrets shedding virus in nasal washes at titers on par with ferrets who inhaled higher doses of unaged influenza virus. We describe here an underreported characteristic of influenza viruses, stability in aerosols, and make a direct connection to the role this characteristic plays in influenza transmission. IMPORTANCE Each time a swine influenza virus transmits to a human, it provides an opportunity for the virus to acquire adaptations needed for sustained human-to-human transmission. Here, we use aerobiology techniques to test the stability of swine-origin H1 subtype viruses in aerosols and evaluate their infectivity in ferrets. Our results show that highly transmissible influenza viruses display enhanced stability in an aerosol state compared to viruses that do not transmit as efficiently. Similar to human-adapted strains, swine-origin influenza viruses are infectious in ferrets at low doses even after prolonged suspension in the air. These data underscore the risk of airborne swine-origin influenza viruses and support the need for continued surveillance and refinement of innovative laboratory methods to investigate mammalian exposure to inhaled pathogens. Determination of the molecular markers that affect the longevity of airborne influenza viruses will improve our ability to quickly identify emerging strains that present the greatest threat to public health.

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.

scholarly journals THE INCIDENCE OF NEUTRALIZING ANTIBODIES FOR HUMAN INFLUENZA VIRUS IN THE SERUM OF HUMAN INDIVIDUALS OF DIFFERENT AGES

1936 ◽  
Vol 63 (5) ◽  
pp. 655-668 ◽  
Author(s):  
Thomas Francis ◽  
T. P. Magill
Keyword(s):  
Influenza Virus ◽  
Neutralizing Antibodies ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
The Other ◽  
Human Influenza ◽  
Complete Protection ◽  
Human Influenza Virus ◽  
Human Sera ◽  
Epidemiological Significance

The results of mouse protection tests with 136 human sera and a strain of human influenza virus are described. After the 1st year of life, the sera of approximately half the individuals tested contained sufficient antibody to furnish complete protection to mice. A much higher percentage of the sera obtained from individuals recently convalescent from influenza exerted a completely protective effect. On the other hand, certain sera protected only partially under the conditions of the tests. The results have been compared with those obtained by Shope in tests done with the same sera against swine influenza virus. The possible epidemiological significance of the results is discussed.

scholarly journals Effect of health seeking interval on outcome in swine flu cases attended a tertiary care hospital in southern Rajasthan region of India

2019 ◽  
Vol 6 (7) ◽  
pp. 2910
Author(s):  
Shalabh Sharma ◽  
Yogesh Kumar Singhal
Keyword(s):  
Influenza Virus ◽  
Clinical Care ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
Influenza Viruses ◽  
Swine Flu ◽  
Care Hospital ◽  
Health Seeking ◽  
Early Presentation ◽  
Number Of Patients

Background: Swine flu influenza is an infection by H1N1 type of swine influenza virus. Swine influenza virus or swine-origin influenza virus (SIV or S-OIV) is a strain of the family of influenza viruses that’s endemic in swine (pigs). Early diagnosis and treatment is key approach to control the morbidity and mortality associated with swine flu which can be achieved by improving health seeking behaviour of community. Understanding of behaviour of community is essential for planning strategies for prevention and control. Aim of this study is to establish a relation between healthcare interval and outcome of swine flu.Methods: A complete data of all the patients visiting swine flu OPDs, swine flu wards and ICU were maintained for year 2015. Each patient visiting either the swine flu OPD or the swine flu ward, who was suspected clinically to be H1N1 positive were tested for real time PCR. Data was collected in a standardized pre-structured questionnaire.Results: Out of 1247 samples tested for rt-PCR, number of patients found to be swine positive was 491 (39.37%). Total 267 patients were admitted in swine flu ward and ICU, out of them 62 was expired. Clinical care intervals of more than 5 days from onset of symptoms to swab collection, diagnosis and admission were more in female and rural population. Mean duration between onset of symptom to hospitalization, swab collection and diagnosis was significantly higher in deceased patients than survived.Conclusions: Early presentation to healthcare facility is associated with better prognosis and outcome. After patient report to the health care setup, early sample collection and diagnosis help to reduce mortality.

scholarly journals Immunization of Pigs with a Particle-Mediated DNA Vaccine to Influenza A Virus Protects against Challenge with Homologous Virus

1998 ◽  
Vol 72 (2) ◽  
pp. 1491-1496 ◽  
Author(s):  
Michael D. Macklin ◽  
Dennis McCabe ◽  
Martha W. McGregor ◽  
Veronica Neumann ◽  
Todd Meyer ◽  
...  
Keyword(s):  
Immune Response ◽  
Influenza Virus ◽  
Influenza A Virus ◽  
Dna Vaccine ◽  
Influenza A ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
Humoral Response ◽  
Preclinical Model ◽  
Homologous Virus

ABSTRACT Particle-mediated delivery of a DNA expression vector encoding the hemagglutinin (HA) of an H1N1 influenza virus (A/Swine/Indiana/1726/88) to porcine epidermis elicits a humoral immune response and accelerates the clearance of virus in pigs following a homotypic challenge. Mucosal administration of the HA expression plasmid elicits an immune response that is qualitatively different than that elicited by the epidermal vaccination in terms of inhibition of the initial virus infection. In contrast, delivery of a plasmid encoding an influenza virus nucleoprotein from A/PR/8/34 (H1N1) to the epidermis elicits a strong humoral response but no detectable protection in terms of nasal virus shed. The efficacy of the HA DNA vaccine was compared with that of a commercially available inactivated whole-virus vaccine as well as with the level of immunity afforded by previous infection. The HA DNA and inactivated viral vaccines elicited similar protection in that initial infection was not prevented, but subsequent amplification of the infection is limited, resulting in early clearance of the virus. Convalescent animals which recovered from exposure to virulent swine influenza virus were completely resistant to infection when challenged. The porcine influenza A virus system is a relevant preclinical model for humans in terms of both disease and gene transfer to the epidermis and thus provides a basis for advancing the development of DNA-based vaccines.

scholarly journals Resurrected ancestral influenza A viruses recapitulate the avian-to-mammalian adaptation of European avian-like swine influenza virus

2021 ◽  
Author(s):  
Wen Su ◽  
Rhodri Harfoot ◽  
Yvonne Su ◽  
Jennifer DeBeauchamp ◽  
Udayan Joseph ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Avian Influenza ◽  
Influenza A ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
Polymerase Activity ◽  
Influenza Viruses ◽  
Mammalian Host ◽  
Influenza A Viruses ◽  
Sequence Reconstruction

Abstract The emergence of a pandemic influenza virus may be better anticipated if we better understand the evolutionary steps taken by avian influenza viruses as they adapt to mammals. We used ancestral sequence reconstruction to resurrect viruses representing initial adaptive stages of the European avian-like H1N1 virus as it transitioned from avian to swine hosts. We demonstrate that efficient transmissibility in pigs was gained through stepwise adaptation after 1983. These time-dependent adaptations resulted in changes in hemagglutinin receptor binding specificity and increased viral polymerase activity. An NP-R351K mutation under strong positive selection increased the transmissibility of a reconstructed virus. The stepwise-adaptation of a wholly avian influenza virus to a mammalian host suggests a window where targeted intervention may have highest impact. Successful intervention will, however, require strategic coordination of surveillance and risk assessment activities to identify these adapting viruses and guide pandemic preparedness resources.

Sign in / Sign up

Export Citation Format

Share Document