Serological evidence of pig-to-human influenza virus transmission on Thai swine farms

Kitikoon, Pravina; Sreta, Donruethai; Tuanudom, Ranida; Amonsin, Alongkorn; Suradhat, Sanipa; Oraveerakul, Kanisak; Poovorawan, Yong; Thanawongnuwech, Roongroje

doi:10.1016/j.vetmic.2010.09.019

Cited by 27 publications

(32 citation statements)

References 14 publications

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“…With regard to other SIV strains other than A(H1N1)pdm09, previous studies found an increased risk of seropositivity to at least one SIV in pig workers, including H1N1,17, 18, 27, 29, 31, 33, 41, 42, 43 H1N218, 28, 31 and H3N228, 29, 30, 44 strains. In our study, we found increased risk of seropositivity both to swine H1N2 and H3N2 Perth.…”

Section: Discussionmentioning

confidence: 98%

Increased risk of A(H1N1)pdm09 influenza infection in UK pig industry workers compared to a general population cohort

Fragaszy

Ishola

Brown

et al. 2016

Influenza Resp Viruses

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BackgroundPigs are mixing vessels for influenza viral reassortment, but the extent of influenza transmission between swine and humans is not well understood.ObjectivesTo assess whether occupational exposure to pigs is a risk factor for human infection with human and swine‐adapted influenza viruses.Methods UK pig industry workers were frequency‐matched on age, region, sampling month, and gender with a community‐based comparison group from the Flu Watch study. HI assays quantified antibodies for swine and human A(H1) and A(H3) influenza viruses (titres ≥ 40 considered seropositive and indicative of infection). Virus‐specific associations between seropositivity and occupational pig exposure were examined using multivariable regression models adjusted for vaccination. Pigs on the same farms were also tested for seropositivity.ResultsForty‐two percent of pigs were seropositive to A(H1N1)pdm09. Pig industry workers showed evidence of increased odds of A(H1N1)pdm09 seropositivity compared to the comparison group, albeit with wide confidence intervals (CIs), adjusted odds ratio after accounting for possible cross‐reactivity with other swine A(H1) viruses (aOR) 25·3, 95% CI (1·4–536·3), P = 0·028.ConclusionThe results indicate that A(H1N1)pdm09 virus was common in UK pigs during the pandemic and subsequent period of human A(H1N1)pdm09 circulation, and occupational exposure to pigs was a risk factor for human infection. Influenza immunisation of pig industry workers may reduce transmission and the potential for virus reassortment.

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Section: Discussionmentioning

confidence: 98%

Increased risk of A(H1N1)pdm09 influenza infection in UK pig industry workers compared to a general population cohort

Fragaszy

Ishola

Brown

et al. 2016

Influenza Resp Viruses

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“…This setting would thus seem to be especially suitable for the circulation of diverse strains of human as well as zoonotic influenza viruses, with the potential for virus coinfection and production of reassortants. Indeed, numerous reassortants between pH1N1 and other influenza viruses have been reported 10, 16, 17, 18, 19, 20, 42, 43, 44. Although the small number of animals on backyard farms and limited transference of animals between farms may limit the potential for virus transmission between swine, continued intensive surveillance for influenza virus reassortants in backyard farms is warranted.…”

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%

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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“…The environment and lifestyle on swine farms in southern China facilitates close contact between domestic poultry, pigs, and humans, increasing the likelihood of interspecies transmission and generation of novel influenza viruses through reassortment (11,14,15). A number of influenza viruses have been isolated in the past from pigs in southern China, including the classical swine H1N1, human-like H1N1, avian-like H1N1, and human-like H3N2 viruses; the double-reassortant H3N2 virus containing genes from human and avian influenza viruses; the triple-reassortant H3N2 virus containing …”

Section: Discussionmentioning

confidence: 99%

“…HI-positive sera from humans were tested for neutralizing antibodies using a traditional micro-neutralization method (10). HI titers AE80 and neutralization (NT) titers AE80 were considered as positive evidence of previous infection (11).…”

Section: Methodsmentioning

confidence: 99%

Avian-Like A (H1N1) Swine Influenza Virus Antibodies among Swine Farm Residents and Pigs in Southern China

et al. 2014

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Serological evidence of pig-to-human influenza virus transmission on Thai swine farms

Cited by 27 publications

References 14 publications

Increased risk of A(H1N1)pdm09 influenza infection in UK pig industry workers compared to a general population cohort

Increased risk of A(H1N1)pdm09 influenza infection in UK pig industry workers compared to a general population cohort

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

Avian-Like A (H1N1) Swine Influenza Virus Antibodies among Swine Farm Residents and Pigs in Southern China

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