Direct detection of influenza virus antigen in nasopharyngeal specimens by direct enzyme immunoassay in comparison with quantitating virus shedding.

Equine influenza virus (EIV) is a major cause of respiratory disease in horses. Vaccination is an effective tool for infection control. Although various EIV vaccines are widely available, major outbreaks occurred in Europe in 2018 involving a new EIV H3N8 FC1 strain. In France, it was reported that both unvaccinated and vaccinated horses were affected despite >80% vaccination coverage and most horses being vaccinated with a vaccine expressing FC1 antigen. This study assessed whether vaccine type, next to antigenic difference between vaccine and field strain, plays a role. Horses were vaccinated with an ISCOMatrix-adjuvanted, whole inactivated virus vaccine (Equilis Prequenza) and experimentally infected with the new FC1 outbreak strain. Serology (HI), clinical signs, and virus shedding were evaluated in vaccinated compared to unvaccinated horses. Results showed a significant reduction in clinical signs and a lack of virus shedding in vaccinated horses compared to unvaccinated controls. From these results, it can be concluded that Equilis Prequenza provides a high level of protection to challenge with the new FC1 outbreak strain. This suggests that, apart from antigenic differences between vaccine and field strain, other aspects of the vaccine may also play an important role in determining field efficacy.

Download Full-text

Sequential Seasonal H1N1 Influenza Virus Infections Protect Ferrets against Novel 2009 H1N1 Influenza Virus

Journal of Virology ◽

10.1128/jvi.02257-12 ◽

2012 ◽

Vol 87 (3) ◽

pp. 1400-1410 ◽

Cited By ~ 45

Author(s):

Donald M. Carter ◽

Chalise E. Bloom ◽

Eduardo J. M. Nascimento ◽

Ernesto T. A. Marques ◽

Jodi K. Craigo ◽

...

Keyword(s):

Influenza Virus ◽

H1n1 Influenza ◽

Cross Reactivity ◽

Influenza Viruses ◽

The Novel ◽

Virus Infections ◽

H1n1 Influenza Virus ◽

Virus Shedding ◽

2009 H1n1 ◽

Novel H1n1 Influenza

ABSTRACTIndividuals <60 years of age had the lowest incidence of infection, with ∼25% of these people having preexisting, cross-reactive antibodies to novel 2009 H1N1 influenza. Many people >60 years old also had preexisting antibodies to novel H1N1. These observations are puzzling because the seasonal H1N1 viruses circulating during the last 60 years were not antigenically similar to novel H1N1. We therefore hypothesized that a sequence of exposures to antigenically different seasonal H1N1 viruses can elicit an antibody response that protects against novel 2009 H1N1. Ferrets were preinfected with seasonal H1N1 viruses and assessed for cross-reactive antibodies to novel H1N1. Serum from infected ferrets was assayed for cross-reactivity to both seasonal and novel 2009 H1N1 strains. These results were compared to those of ferrets that were sequentially infected with H1N1 viruses isolated prior to 1957 or more-recently isolated viruses. Following seroconversion, ferrets were challenged with novel H1N1 influenza virus and assessed for viral titers in the nasal wash, morbidity, and mortality. There was no hemagglutination inhibition (HAI) cross-reactivity in ferrets infected with any single seasonal H1N1 influenza viruses, with limited protection to challenge. However, sequential H1N1 influenza infections reduced the incidence of disease and elicited cross-reactive antibodies to novel H1N1 isolates. The amount and duration of virus shedding and the frequency of transmission following novel H1N1 challenge were reduced. Exposure to multiple seasonal H1N1 influenza viruses, and not to any single H1N1 influenza virus, elicits a breadth of antibodies that neutralize novel H1N1 even though the host was never exposed to the novel H1N1 influenza viruses.

Download Full-text

Prevention of influenza virus shedding and protection from lethal H1N1 challenge using a consensus 2009 H1N1 HA and NA adenovirus vector vaccine

Vaccine ◽

10.1016/j.vaccine.2011.07.073 ◽

2011 ◽

Vol 29 (40) ◽

pp. 7020-7026 ◽

Cited By ~ 17

Author(s):

Frank R. Jones ◽

Elizabeth S. Gabitzsch ◽

Younong Xu ◽

Joseph P. Balint ◽

Viktoriya Borisevich ◽

...

Keyword(s):

Influenza Virus ◽

Adenovirus Vector ◽

Virus Shedding ◽

Vector Vaccine ◽

2009 H1n1

Download Full-text

Heterotypic immunity to influenza in ferrets

Infection and Immunity ◽

10.1128/iai.29.2.650-653.1980 ◽

1980 ◽

Vol 29 (2) ◽

pp. 650-653

Author(s):

R A Yetter ◽

W H Barber ◽

P A Small

Keyword(s):

Influenza Virus ◽

Type A ◽

Influenza Viruses ◽

Virus Shedding

Heterotypic immunity to influenza virus in ferrets operated against heterotypic influenza viruses but not heterologous viruses. Contrary to prior reports, the protection conferred lasted for at least 18 months. This type of immunity limited virus shedding but did not prevent infection. These results suggest that this phenomenon could play a role in determining the severity of infections caused by type A influenza viruses in humans.

Download Full-text

Simian rhesus rotavirus is a unique heterologous (non-lapine) rotavirus strain capable of productive replication and horizontal transmission in rabbits

Microbiology ◽

10.1099/0022-1317-81-5-1237 ◽

2000 ◽

Vol 81 (5) ◽

pp. 1237-1249 ◽

Cited By ~ 22

Author(s):

Max Ciarlet ◽

Mary K. Estes ◽

Margaret E. Conner

Keyword(s):

Horizontal Transmission ◽

Amino Acid Identity ◽

Virus Antigen ◽

Structural Protein ◽

Gene Encoding ◽

Range Restriction ◽

Infectious Dose ◽

Virus Shedding ◽

Inoculum Dose ◽

Productive Replication

Simian rhesus rotavirus (RRV) is the only identified heterologous (non-lapine) rotavirus strain capable of productive replication at a high inoculum dose of virus (>108 p.f.u.) in rabbits. To evaluate whether lower doses of RRV would productively infect rabbits and to obtain an estimate of the 50% infectious dose, rotavirus antibody-free rabbits were inoculated orally with RRV at inoculum doses of 103, 105 or 107 p.f.u. Based on faecal virus antigen or infectious virus shedding, RRV replication was observed with inoculum doses of 107 and 105 p.f.u., but not 103 p.f.u. Horizontal transmission of RRV to one of three mock-inoculated rabbits occurred 4–5 days after onset of virus antigen shedding in RRV-infected rabbits. Rabbits infected at 107 and 105, but not 103, p.f.u. of RRV developed rotavirus-specific immune responses and were completely (100%) protected from lapine ALA rotavirus challenge. These data confirm that RRV can replicate productively and spread horizontally in rabbits. In attempts to elucidate the genetic basis of the unusual replication efficacy of RRV in rabbits, the sequence of the gene encoding the lapine non-structural protein NSP1 was determined. Sequence analysis of the NSP1 of three lapine rotaviruses revealed a high degree of amino acid identity (85–88%) with RRV. Since RRV and lapine strains also share similar VP7s (96–97%) and VP4s (69–70%), RRV might replicate efficiently in rabbits because of the high relatedness of these three gene products, each implicated in host range restriction.

Download Full-text

DISSOCIATION OF HEMAGGLUTINATING AND ANTIBODY-MEASURING CAPACITIES OF INFLUENZA VIRUS

Journal of Experimental Medicine ◽

10.1084/jem.85.1.1 ◽

1947 ◽

Vol 85 (1) ◽

pp. 1-7 ◽

Cited By ~ 88

Author(s):

Thomas Francis

Keyword(s):

Influenza Virus ◽

Specific Antibody ◽

Serum Antibody ◽

Allantoic Fluid ◽

Virus Antigen ◽

Normal Serum ◽

Type B ◽

Heat Stable ◽

Labile Component ◽

Type B Influenza Virus

Preparations of Type B influenza virus, propagated in the embryonated egg and obtained in the form of allantoic fluid, were found after heating at 56°C. for 30 minutes to retain the capacity to agglutinate erythrocytes but no longer measured specific antibody when used as antigen in titrations of serum antibody. The dissociation of the two activities suggests the presence in such virus preparations of a complex virus antigen comprising, (1) a heat-stable component which agglutinates erythrocytes and reacts primarily with specific antibody; (2) a heat-labile component reacting with a factor of normal serum which ordinarily tends to inhibit the hemagglutinating activity of influenza virus. The relation of the reagents to other known serological activities of influenza virus is being studied.

Download Full-text