Diagnostics and Surveillance for Swine Influenza

Detmer, Susan E.; Gramer, Marie; Goyal, Sagar M.; Torremorell, Montserrat; Torrison, Jerry

doi:10.1007/82_2012_220

Cited by 30 publications

(48 citation statements)

References 96 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A recent well-referenced review article describes the various tests used in the diagnosis of influenza virus infection in swine and addresses attributes and rationale behind influenza surveillance systems. 25 …”

Section: Diagnosis Of Influenza Virus Infections In Swinementioning

confidence: 99%

Influenza A Virus Infections in Swine

Janke

2013

Vet Pathol

View full text Add to dashboard Cite

Influenza has been recognized as a respiratory disease in swine since its first appearance concurrent with the 1918 ''Spanish flu'' human pandemic. All influenza viruses of significance in swine are type A, subtype H1N1, H1N2, or H3N2 viruses. Influenza viruses infect epithelial cells lining the surface of the respiratory tract, inducing prominent necrotizing bronchitis and bronchiolitis and variable interstitial pneumonia. Cell death is due to direct virus infection and to insult directed by leukocytes and cytokines of the innate immune system. The most virulent viruses consistently express the following characteristics of infection: (1) higher or more prolonged virus replication, (2) excessive cytokine induction, and (3) replication in the lower respiratory tract. Nearly all the viral proteins contribute to virulence. Pigs are susceptible to infection with both human and avian viruses, which often results in gene reassortment between these viruses and endemic swine viruses. The receptors on the epithelial cells lining the respiratory tract are major determinants of infection by influenza viruses from other hosts. The polymerases, especially PB2, also influence cross-species infection. Methods of diagnosis and characterization of influenza viruses that infect swine have improved over the years, driven both by the availability of new technologies and by the necessity of keeping up with changes in the virus. Testing of oral fluids from pigs for virus and antibody is a recent development that allows efficient sampling of large numbers of animals.Keywords influenza virus, swine, pathogenesis, cytokines, apoptosis, virulence, cross-species infection, hemagglutinin, receptors, polymerases, diagnosisThe evolution and epidemiology of influenza A virus (IAV) infections in swine have been integrally tied to the segmented nature of the genome of the virus, which facilitates gene reassortment, and to the adaptability of these genes through mutation, which sometimes facilitates replication in a new host. 8,19,77,85,89 Influenza was first recognized as a respiratory disease entity in swine during the 1918 human Spanish flu pandemic. 67 The virus was not isolated until 1931, when nasal discharge from pigs was inoculated into ferrets and subsequently into embryonated chicken eggs. 129 In 1933, a similar virus was recovered from humans with this technique. 131 The viruses were essentially identical and served as the prototype for type A subtype H1N1 influenza viruses.All influenza viruses of significance that infect swine are type A viruses, defined by the highly conserved internal nucleoproteins and matrix proteins. Influenza A virus subtypes are based on the external hemagglutinin (HA) and neuraminidase (NA) proteins. The predominant viruses in swine populations in different parts of the world may have genes of different origin, even though the subtypes may be similar. 10,73,171 The original classic H1N1 swine influenza virus, which remained the predominant influenza virus in North American swine populations for nearl...

show abstract

Section: Diagnosis Of Influenza Virus Infections In Swinementioning

confidence: 99%

Influenza A Virus Infections in Swine

Janke

2013

Vet Pathol

View full text Add to dashboard Cite

show abstract

“…O diagnóstico definitivo de influenza só é possível por meio de análise laboratorial das amostras coletadas, uma vez que os achados clínico-patológicos são presuntivos, mas não confirmatórios da doença (Janke 1995, Detmer et al 2012. Os testes laboratoriais comumente usados para o diagnóstico de influenza A são: a) isolamento viral para a detecção do agente, b) testes moleculares para a detecção de material genético viral, c) testes sorológicos para a demonstração de anticorpos específicos para o vírus, e d) análise histopatológica e IHQ para a identificação de lesões microscópicas e detecção do antígeno viral, respectivamente (Van Reeth et al 2012).…”

Section: Testes Diagnósticos E Interpretação Dos Resultadosunclassified

“…A excreção viral diminui por volta de seis a oito dias pós-infecção (Detmer et al 2012). A transmissão ocorre por contato direto entre os suínos por meio das secreções nasais de suínos infectados/doentes.…”

Section: Influenza Em Suínosunclassified

“…Utilizam-se como vírus de referência os subtipos virais mais prevalentes em determinada região ou País. O resultado com títulos de HI iguais ou maiores que 1:40 indica que há proteção contra o subtipo viral testado (Detmer et al 2012). Por exemplo, no Brasil os subtipos de influenza encontrados em suínos são H1N1, H3N2 (Brentano et al 2002), H1N2 ) e A(H1N1)pdm09 (Schaefer et al 2011), sendo todos esses subtipos utilizados como vírus de referência no teste de HI.…”

Section: Testes Sorológicos Para Detecção De Anticorposunclassified

See 1 more Smart Citation

Orientações para o diagnóstico de influenza em suínos

et al. 2013

View full text Add to dashboard Cite

Este trabalho descreve a colheita adequada de amostras, as técnicas/procedimentos disponíveis para o diagnóstico de influenza A em suínos, assim como os resultados e suas respectivas interpretações, para auxiliar médicos veterinários de campo na identificação dessa doença. Em suínos vivos, as amostras adequadas são: secreção nasal, fluido oral e sangue (soro). Para suínos mortos, colher preferencialmente amostras de pulmão com consolidação cranioventral. Secreção nasal e fragmentos de pulmão refrigerado são utilizados para detectar partícula viral viável (isolamento viral - IV) ou ácido nucleico viral (RT-PCR convencional e RT-PCR em tempo real). As amostras não devem ser congeladas, pois o vírus é inativado a -20°C. A caracterização molecular dos isolados é feita pela análise filogenética obtida pelo sequenciamento de DNA. O soro é utilizado para a detecção de anticorpos (Acs) por meio do teste da inibição da hemaglutinação e ELISA. O fluido oral pode ser utilizado para detecção de anticorpo (ELISA) ou de vírus. Fragmentos de pulmão fixados em formol a 10% são examinados microscopicamente para identificar pneumonia broncointersticial e para detecção de antígeno viral pela imuno-histoquímica (IHQ). Para o sucesso do diagnóstico, as amostras devem ser colhidas de suínos que estão preferencialmente na fase aguda da doença, para aumentar as chances de detecção viral. As melhores opções para o diagnóstico de influenza A em suínos vivos são RT-PCR e isolamento viral de amostras de swab nasal ou fluido oral. Pulmão para análise por RT-PCR, isolamento viral ou IHQ é a amostra de escolha em suínos mortos. Testes sorológicos têm valor diagnóstico limitado e são utilizados apenas para determinar o estado imune do rebanho, não indicando doença clínica, pois os Acs são detectados 7-10 dias pós-infecção (fase subaguda). O diagnóstico de influenza é importante para avaliar o envolvimento desse agente no complexo de doença respiratória suína. Além disso, o isolamento do vírus influenza é essencial para o monitoramento dos principais subtipos circulantes em uma determinada região ou país, assim como para a detecção de novos rearranjos virais, já que influenza é considerada uma zoonose.

show abstract

“…Real-time RT-PCR (RT-qPCR) has provided ample applications for rapid and sensitive molecular virological diagnosis [14]. Serology in swine influenza has been found useful for retrospective epidemiological investigations e.g., [15], estimation of disease incidence e.g., [16], and control of vaccination success e.g., [17].…”

Section: Introductionmentioning

confidence: 99%

Distinction of subtype-specific antibodies against European porcine influenza viruses by indirect ELISA based on recombinant hemagglutinin protein fragment-1

Zhao

Lange

Kubald

et al. 2013

Virol J

View full text Add to dashboard Cite

BackgroundSerological investigations of swine influenza virus infections and epidemiological conclusions thereof are challenging due to the complex and regionally variable pattern of co-circulating viral subtypes and lineages and varying vaccination regimes. Detection of subtype-specific antibodies currently depends on hemagglutination inhibition (HI) assays which are difficult to standardize and unsuitable for large scale investigations.MethodsThe nucleocapsid protein (NP) and HA1 fragments of the hemagglutinin protein (HA) of five different lineages (H1N1av, H1N1pdm, H1pdmN2, H1N2, H3N2) of swine influenza viruses were bacterially expressed and used as diagnostic antigens in indirect ELISA.ResultsProteins were co-translationally mono-biotinylated and refolded in vitro into an antigenically authentic conformation. Western blotting and indirect ELISA revealed highly subtype-specific antigenic characteristics of the recombinant HA1 proteins although some cross reactivity especially among antigens of the H1 subtype were evident. Discrimination of antibodies directed against four swine influenza virus subtypes co-circulating in Germany was feasible using the indirect ELISA format.ConclusionsBacterially expressed recombinant NP and HA1 swine influenza virus proteins served as antigens in indirect ELISAs and provided an alternative to commercial blocking NP ELISA and HI assays concerning generic (NP-specific) and HA subtype-specific sero-diagnostics, respectively, on a herd basis.

show abstract

Diagnostics and Surveillance for Swine Influenza

Cited by 30 publications

References 96 publications

Influenza A Virus Infections in Swine

Influenza A Virus Infections in Swine

Orientações para o diagnóstico de influenza em suínos

Distinction of subtype-specific antibodies against European porcine influenza viruses by indirect ELISA based on recombinant hemagglutinin protein fragment-1

Contact Info

Product

Resources

About