Swine Outbreak of Pandemic Influenza A Virus on a Canadian Research Farm Supports Human-to-Swine Transmission

Forgie, Sarah; Keenliside, Julia; Wilkinson, Craig W.; Webby, Richard J.; Lu, Patricia; Sørensen, Ole E.; Fonseca, Kevin; Barman, Subrata; Rubrum, Adam; Stigger, Evelyn; Marrie, Thomas J.; Marshall, Frank; Spady, Donald W.; Hu, Jia; Loeb, Mark; Russell, Margaret L.; Babiuk, Lorne A.

doi:10.1093/cid/ciq030

Cited by 80 publications

(78 citation statements)

References 20 publications

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“…Although experimental infections in the laboratory confirm the potential for pH1N1 virus shedding and contact transmission between swine,20, 40 most field investigations suggest that sustained transmission among swine is limited in small‐scale farm settings5, 14 although, as infection is often subclinical or associated with mild disease,4, 9 it may go undetected 40. Consistent with this, none of the swine in our study were noted to be sick prior to slaughter and no abnormalities were noted on gross anatomic examination of the lungs of the three virus‐positive animals.…”

Section: Discussionmentioning

confidence: 99%

“…The influenza A(H1N1)pdm09 virus (pH1N1) was first identified among humans in March 2009 and generated the first pandemic of the 21st century 3. Since 2009, pH1N1 has become endemic in human populations globally and there have been numerous reports of human‐to‐swine transmission 1, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20. Most of these reports, however, have focused on larger scale industrial farms,4, 7, 11, 18 as opposed to smaller scale backyard farms, despite the fact that large numbers of pigs are raised in backyard settings, particularly in developing countries, providing considerable opportunity for influenza virus transmission between humans and livestock 21, 22…”

Section: Introductionmentioning

confidence: 99%

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Transmission dynamics of pandemic influenza A(H1N1)pdm09 virus in humans and swine in backyard farms in Tumbes, Peru

Tinoco

Kasper

Nelson

et al. 2015

Influenza Resp Viruses

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ObjectivesWe aimed to determine the frequency of pH1N1 transmission between humans and swine on backyard farms in Tumbes, Peru.DesignTwo‐year serial cross‐sectional study comprising four sampling periods: March 2009 (pre‐pandemic), October 2009 (peak of the pandemic in Peru), April 2010 (1st post‐pandemic period), and October 2011 (2nd post‐pandemic period).SampleBackyard swine serum, tracheal swabs, and lung sample were collected during each sampling period.Main outcome measuresWe assessed current and past pH1N1 infection in swine through serological testing, virus culture, and RT‐PCR and compared the results with human incidence data from a population‐based active surveillance cohort study in Peru.ResultsAmong 1303 swine sampled, the antibody prevalence to pH1N1 was 0% pre‐pandemic, 8% at the peak of the human pandemic (October 2009), and 24% in April 2010 and 1% in October 2011 (post‐pandemic sampling periods). Trends in swine seropositivity paralleled those seen in humans in Tumbes. The pH1N1 virus was isolated from three pigs during the peak of the pandemic. Phylogenetic analysis revealed that these viruses likely represent two separate human‐to‐swine transmission events in backyard farm settings.ConclusionsOur findings suggest that human‐to‐swine pH1N1 transmission occurred during the pandemic among backyard farms in Peru, emphasizing the importance of interspecies transmission in backyard pig populations. Continued surveillance for influenza viruses in backyard farms is warranted.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Transmission dynamics of pandemic influenza A(H1N1)pdm09 virus in humans and swine in backyard farms in Tumbes, Peru

Tinoco

Kasper

Nelson

et al. 2015

Influenza Resp Viruses

View full text Add to dashboard Cite

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“…2010, Song et al 2010, Forgie et al 2011, CDC 2012, Gray et al 2012, Williamson et al 2012). Swine workers and their family members are at increased risk of contracting swine influenza virus infections ( Olsen et al 2002, Myers et al 2006, Gray et al 2007, Robinson et al 2007, Yassine et al 2009, Beaudoin et al 2012, CDC 2012, Wong et al 2012).…”

Section: Discussionmentioning

confidence: 99%

“…Sixty-seven percent of humans and 94% of swine with positive laboratory tests results had few or no symptoms (Forgie et al 2011). …”

Section: Discussionmentioning

confidence: 99%

Influenza A virus infection of healthy piglets in an abattoir in Brazil: animal-human interface and risk for interspecies transmission

Amorim

Fornells

Reis

et al. 2013

Mem. Inst. Oswaldo Cruz

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Asymptomatic influenza virus infections in pigs are frequent and the lack of measures for controlling viral spread facilitates the circulation of different virus strains between pigs. The goal of this study was to demonstrate the circulation of influenza A virus strains among asymptomatic piglets in an abattoir in Brazil and discuss the potential public health impacts. Tracheal samples (n = 330) were collected from asymptomatic animals by a veterinarian that also performed visual lung tissue examinations. No slaughtered animals presented with any noticeable macroscopic signs of influenza infection following examination of lung tissues. Samples were then analysed by reverse transcription-polymerase chain reaction that resulted in the identification of 30 (9%) influenza A positive samples. The presence of asymptomatic pig infections suggested that these animals could facilitate virus dissemination and act as a source of infection for the herd, thereby enabling the emergence of influenza outbreaks associated with significant economic losses. Furthermore, the continuous exposure of the farm and abattoir workers to the virus increases the risk for interspecies transmission. Monitoring measures of swine influenza virus infections and vaccination and monitoring of employees for influenza infection should also be considered. In addition regulatory agencies should consider the public health ramifications regarding the potential zoonotic viral transmission between humans and pigs.

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“…It suggests the humans as possible sources of infection of pH1N1 for pigs. Recently, Forgie et al (2011) have shown data based on epidemiologic and clinical findings that give support to human-to-swine transmission of the pH1N1 in a swine research farm in Alberta, Canada.…”

Section: Discussionmentioning

confidence: 99%

Isolamento e caracterização do vírus da influenza pandêmico H1N1 em suínos no Brasil

et al. 2011

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761Pesq. Vet. Bras. 31(9):761-767, setembro 2011 RESUMO.-[Isolamento e caracterização do vírus da influenza pandêmico H1N1 em suínos no Brasil.] A infecção causada pelo vírus Influenza A (IAV) é endêmica em suí-nos no mundo inteiro. O surgimento da pandemia de influenza humana pelo vírus A/H1N1 (pH1N1) em 2009 levantou dúvi-das sobre a ocorrência deste vírus em suínos no Brasil. Durante o desenvolvimento de um projeto de pesquisa do vírus de influenza suína em 2009-2010, na Embrapa Suínos e Aves (CNPSA), foi detectado em um rebanho de suínos em Santa Catarina, Brasil, um surto de influenza altamente transmissí-vel causado pelo subtipo viral H1N1. Este vírus causou uma doença leve em suínos em crescimento e em fêmeas adultas, sem mortalidade. Tres leitões clinicamente afetados foram eutanasiados. As lesões macroscópicas incluiam consolidação leve a moderada das áreas cranioventrais do pulmão. Microscopicamente, as lesões foram caracterizadas por bronquiolite necrosante obliterativa e pneumonia broncointersticial. A imunohistoquímica, utilizando um anticorpo monoclonal contra a nucleoproteína do vírus influenza A, revelou marcação positiva no núcleo das células epiteliais bronquiolares. O tecido pulmonar de três leitões e os suabes nasais de cinco fêmeas e quatro leitões foram positivos para influenza A pela RT-PCR. O vírus influenza foi isolado de um pulmão, mais tarde sendo confirmado pelo teste de hemaglutinação (título HA 1:128) e por RT-PCR. A análise das seqüências de nucleotídeos dos genes da hemaglutinina (HA) e proteína da matriz (M) revelou que o vírus isolado foi consistente com o vírus pandêmico A/H1N1/ 2009 que circulou em humanos no mesmo período. Este é o primeiro relato de um surto de influenza causado pelo vírus pandêmico A/H1N1 em suínos no Brasil.

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Swine Outbreak of Pandemic Influenza A Virus on a Canadian Research Farm Supports Human-to-Swine Transmission

Cited by 80 publications

References 20 publications

Transmission dynamics of pandemic influenza A(H1N1)pdm09 virus in humans and swine in backyard farms in Tumbes, Peru

Transmission dynamics of pandemic influenza A(H1N1)pdm09 virus in humans and swine in backyard farms in Tumbes, Peru

Influenza A virus infection of healthy piglets in an abattoir in Brazil: animal-human interface and risk for interspecies transmission

Isolamento e caracterização do vírus da influenza pandêmico H1N1 em suínos no Brasil

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