title: Reverse zoonotic disease transmission (zooanthroponosis): a systematic review of seldom-documented human biological threats to animals.
abstract: BACKGROUND
  Research regarding zoonotic diseases often focuses on infectious diseases animals have given to humans. However, an increasing number of reports indicate that humans are transmitting pathogens to animals. Recent examples include methicillin-resistant Staphylococcus aureus, influenza A virus, Cryptosporidium parvum, and Ascaris lumbricoides. The aim of this review was to provide an overview of published literature regarding reverse zoonoses and highlight the need for future work in this area.
  
  
  METHODS
  An initial broad literature review yielded 4763 titles, of which 4704 were excluded as not meeting inclusion criteria. After careful screening, 56 articles (from 56 countries over three decades) with documented human-to-animal disease transmission were included in this report.
  
  
  RESULTS
  In these publications, 21 (38%) pathogens studied were bacterial, 16 (29%) were viral, 12 (21%) were parasitic, and 7 (13%) were fungal, other, or involved multiple pathogens. Effected animals included wildlife (n = 28, 50%), livestock (n = 24, 43%), companion animals (n = 13, 23%), and various other animals or animals not explicitly mentioned (n = 2, 4%). Published reports of reverse zoonoses transmission occurred in every continent except Antarctica therefore indicating a worldwide disease threat.
  
  
  CONCLUSIONS
  As we see a global increase in industrial animal production, the rapid movement of humans and animals, and the habitats of humans and wild animals intertwining with great complexity, the future promises more opportunities for humans to cause reverse zoonoses. Scientific research must be conducted in this area to provide a richer understanding of emerging and reemerging disease threats. As a result, multidisciplinary approaches such as One Health will be needed to mitigate these problems.
authors.affiliation: College of Public Health and Health Professions, University of Florida, Gainesville, Florida, United States of America ; Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Ali M
authors.initials: AM
authors.lastname: Messenger
authors.affiliation: College of Public Health and Health Professions, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Amber N
authors.initials: AN
authors.lastname: Barnes
authors.affiliation: College of Public Health and Health Professions, University of Florida, Gainesville, Florida, United States of America ; Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Gregory C
authors.initials: GC
authors.lastname: Gray
mesh_terms: D000818:Animals; D000829:Animals, Domestic / Q000382:microbiology / Q000821:virology; D000835:Animals, Wild / Q000382:microbiology / Q000821:virology; D003141:Communicable Diseases / Q000382:microbiology / Q000821:virology; D006801:Humans; D009980:Influenza A virus / Q000472:pathogenicity; D055624:Methicillin-Resistant Staphylococcus aureus / Q000472:pathogenicity; D015047:Zoonoses / Q000635:transmission*