page_title: Anthroponotic disease
section_title: Influenza A virus subtype H1N1
hierarchical_section_title: Anthroponotic disease / Cases with modes of transmission / Domesticated livestock animals / Influenza A virus subtype H1N1
caption_attribution_description: English: a) Cross-species transmission between avian species (thought to be the main reservoir for IAV diversity) and humans (H1N1, H2N2, and H3N2), equines [H3N8 (2x) and H7N7], canines (H3N2), and swine (H1N1 and triple reassortant PB2/PA), as well as transmission between mammalian species: equine-to-canine (H3N8), swine-to-human (H1N1), and human-to-swine (H1N1, H1N2, and H3N2, at least 20 times). Width of arrows is proportional to the number of IAV transmission events between species that result in endemic circulation of a virus in a new host (transient spillovers not included). (b) Model for the role of swine as ‘mixing vessels’ for the evolution of pandemic viruses (width of arrows also are proportional to the frequency of transmission). (c) Model for the evolution of H3N2v viruses in swine. Large-scale transmission of pH1N1 viruses from humans to swine seeds pH1N1 in swine populations globally (I); reassortment between pH1N1 viruses and co-circulating triple reassortant H3N2 viruses in the United States, generating novel reassortant H3N2v variants with seven triple reassortant H3N2 virus segments and the MP segment of pH1N1 origin (II); and transmission of &gt; 300 H3N2v viruses from swine to humans, resulting in one adult fatality, in the United States during 2011–2013 (III).
context_page_description: Reverse zoonosis, also known as zooanthroponosis, and sometimes anthroponosis, refers to pathogens reservoired in humans that are capable of being transmitted to other non-human animals.
context_section_description: Turkeys: A Norwegian turkey breeder’s flock exhibited a decrease in egg production with no other clinical signs after a farm hand reported having H1N1. A study revealed that the turkeys also had H1N1 and were seropositive to its antigens. Maternally derived H1N1 antibodies were detected in egg yolks and further genetic analyses revealed an identical H1N1 strain in the turkeys as the farm worker who likely infected the turkeys during artificial insemination.
  Pigs: Human to pig H1N1 transmission was reported in Canada, Korea, and eventually came to include every continent save Antarctica during the 2009 outbreak. It has also been known to spread during seasonal epidemics in France between humans and pigs.
caption: Nelson, M. I., & Vincent, A. L. (2015). Reverse zoonosis of influenza to swine: new perspectives on the human-animal interface. Trends in microbiology, 23(3), 142–153. https://doi.org/10.1016/j.tim.2014.12.002
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