The epidemiology of swine influenza

Li, Yin; Robertson, Ian D.

doi:10.1186/s44149-021-00024-6

Cited by 21 publications

(23 citation statements)

References 136 publications

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“…Zoonotic infections of individuals from pigs have raised widespread concern, especially in pig farms ( 24 , 25 ). Likewise, we noticed the trepidation of some pig farmers concerning the high risks of being infected by zoonotic pathogens from pigs, and the requirement for effective preventive measures.…”

Section: Discussionmentioning

confidence: 99%

Pseudorabies in pig industry of China: Epidemiology in pigs and practitioner awareness

Tan

Zhou

et al. 2022

Front. Vet. Sci.

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Pseudorabies virus (PRV) is widely prevalent in China, which can transmit from pigs to other mammals. Moreover, a PRV variant isolated from an acute human encephalitis case was documented recently. It is imperative to investigate PRV epidemiology in pigs, the knowledge regarding pseudorabies (PR) and self-protection behaviors upon working among relevant practitioners including pig farmers, pig cutters, and pork salesman. In the present study, 18,812 pig serum samples and 1,634 tissue samples were collected from Hunan Province during the period of 2020 to 2021 for detecting the presence of PRV gE-special antibody and nucleic acids, respectively. Meanwhile, we conducted a questionnaire survey about PR among these practitioners in China. The results showed that nearly 9% (1,840/20,192) pigs from 161 collected sites (20.17%, 161/797) were seropositive for PRV-gE antibody. Though only 2.33% tissue samples were positive for PRV nucleic acids, all the representative PRV strains were variant. It was learned that most practitioners were frequently injured when working, the injured sites mainly included hand and foot. Among the three transmission routes of PRV, the aerosol transmission route was often overlooked. Moreover, the workers lacked self-protection awareness and were poor conscious about PRV and its potential threat to humans. All the results demonstrate that PRV remains widely spread in pig populations, while the potential threats of PRV in pig industry receive less attention, suggesting that targeted educational programs to these people should be performed.

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Section: Discussionmentioning

confidence: 99%

Pseudorabies in pig industry of China: Epidemiology in pigs and practitioner awareness

Tan

Zhou

et al. 2022

Front. Vet. Sci.

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“…The first documented introduction of human IAV into swine populations occurred in the aftermath of the Spanish flu; this lineage was designated “classical swine” H1N1 (or lineage 1A). Thereafter, the genetic diversity of swIAV has grossly extended due to further incursions of human-derived pandemic and seasonal IAV [ 5 , 14 , 111 ]. In Europe, avian-derived IAV have also contributed to the diversity of swIAV.…”

Section: Reverse Zoonotic Infections Of Swine With Human Iav Occur Fr...mentioning

confidence: 99%

“…Thereby, swIAV compromises animal welfare and invokes economic damage in the pig industry [ 1 , 4 ]. In addition, swine populations have been the source of generating human pandemic IAV as demonstrated in 2009 when a new reassortant IAV of the H1N1 subtype emerged in pigs in Mesoamerica [ 5 ]. This virus harbored gene segments derived from human, avian and porcine origin.…”

Section: Introductionmentioning

confidence: 99%

Are pigs overestimated as a source of zoonotic influenza viruses?

et al. 2022

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Background Swine influenza caused by influenza A viruses (IAV) directly affects respiratory health and indirectly impairs reproduction rates in pigs causing production losses. In Europe, and elsewhere, production systems have intensified featuring fewer holdings but, in turn, increased breeding herd and litter sizes. This seems to foster swine IAV (swIAV) infections with respect to the entrenchment within and spread between holdings. Disease management of swine influenza is difficult and relies on biosecurity and vaccination measures. Recently discovered and widely proliferating forms of self-sustaining modes of swIAV infections in large swine holdings challenge these preventive concepts by generating vaccine-escape mutants in rolling circles of infection. Main body The most recent human IAV pandemic of 2009 rooted at least partly in IAV of porcine origin highlighting the zoonotic potential of swIAV. Pigs constitute a mixing vessel of IAV from different species including avian and human hosts. However, other host species such as turkey and quail but also humans themselves may also act in this way; thus, pigs are not essentially required for the generation of IAV reassortants with a multispecies origin. Since 1918, all human pandemic influenza viruses except the H2N2 virus of 1958 have been transmitted in a reverse zoonotic mode from human into swine populations. Swine populations act as long-term reservoirs of these viruses. Human-derived IAV constitute a major driver of swIAV epidemiology in pigs. Swine-to-human IAV transmissions occurred rarely and mainly sporadically as compared to avian-to-human spill-over events of avian IAV. Yet, new swIAV variants that harbor zoonotic components continue to be detected. This increases the risk that such components might eventually reassort into viruses with pandemic potential. Conclusions Domestic pig populations should not be globally stigmatized as the only or most important reservoir of potentially zoonotic IAV. The likely emergence from swine of the most recent human IAV pandemic in 2009, however, emphasized the principal risks of swine populations in which IAV circulate unimpededly. Implementation of regular and close-meshed IAV surveillance of domestic swine populations to follow the dynamics of swIAV evolution is clearly demanded. Improved algorithms for directly inferring zoonotic potential from whole IAV genome sequences as well as improved vaccines are still being sought.

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“…In addition to vaccination, grower farms may practice all-in all-out practices (with thorough cleaning and disinfection between batches), biosecurity practices such as limiting personnel and showering in and out, purchasing piglets from known sources, surveillance of incoming animals, isolation and quarantine (17,39). Ventilation systems have been shown to reduce the entrance of and transmission of pathogens across different rooms on farms (40)(41)(42)(43).…”

Section: Control Measuresmentioning

confidence: 99%

A stochastic compartmental model to simulate intra- and inter-species influenza transmission in an indoor swine farm

Kontowicz

Moreno-Madriñan

Ragland

et al. 2022

Preprint

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Common in swine production worldwide, influenza causes significant reductions in feed efficiency and potential transmission to the workforce. Swine vaccines are not universally used in swine production, partly due to their limited efficacy because of continuously evolving influenza viruses. We evaluated the effects of vaccination, quarantine of infected pigs, and changes to workforce routine (ensuring workers moved from younger pig batches to older pig batches). A Susceptible-Exposed-Infected-Recovered model was used to simulate stochastic influenza transmission during a single production cycle on an indoor hog growing unit containing 4000 pigs and two workers. The absence of control practices resulted in 3,958 pigs [1 – 3972] being infected and a 0.61 probability of workforce infection. Quarantine of infected pigs the same day they became infectious was the single effective control practice, reducing the number of infected pigs to 3 [1 - 3961] and the probability of workforce infection to 0.27. The second-best control practice was mass pig vaccination (80% effective vaccine), which reduced the number of infected pigs to 23.5 [1 - 635] and the probability of workforce infection to 0.07. The third-best control practice was changing the worker routine by starting with younger to older pig batches, which reduced the number of infected pigs to 997 [1 - 1984] and the probability of workforce infection (0.22). All other control practices, when considered alone, showed little improvement in reducing total infected pigs and the probability of workforce infection. Combining all control strategies reduced the total number of infected pigs to 1 or 2 with a minimal probability of workforce infection (0.03 – 0.01). These findings suggest that non-pharmaceutical interventions can reduce the impact of influenza on swine production and reduce the risk of interspecies transmission when efficacious vaccines are unavailable. Therefore, these results can help prevent the emergence of influenza strains with pandemic potential.

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The epidemiology of swine influenza

Cited by 21 publications

References 136 publications

Pseudorabies in pig industry of China: Epidemiology in pigs and practitioner awareness

Pseudorabies in pig industry of China: Epidemiology in pigs and practitioner awareness

Are pigs overestimated as a source of zoonotic influenza viruses?

A stochastic compartmental model to simulate intra- and inter-species influenza transmission in an indoor swine farm

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