Adaptive pathways of zoonotic influenza viruses: From exposure to establishment in humans

• Published in: Vaccine Vol. 30; no. 30; pp. 4419 - 4434
• Main Authors: Reperant, Leslie A., Kuiken, Thijs, Osterhaus, Albert D.M.E.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 22.06.2012; Elsevier Limited
• Subjects: Adaptation; Adaptation, Biological - genetics; Adaptations; Adaptive changes; Allergy and Immunology; Animals; Avian; Avian flu; Bird migration; Birds; Cross-species transmission; Disease transmission; Host Specificity; Human; human influenza; human population; Humans; Infections; Influenza; Influenza in Birds - transmission; Influenza in Birds - virology; Influenza virus; Influenza, Human - transmission; Influenza, Human - virology; interdisciplinary research; Mammals; monitoring; Mortality; Mutation; Orthomyxoviridae; Orthomyxoviridae - genetics; Orthomyxoviridae - physiology; pandemic; Pandemics; Proteins; Respiratory diseases; Swine; vaccines; vertebrate viruses; Viruses; Zoonoses; Zoonoses - transmission; Zoonoses - virology; Zoonosis; Human; Swine; Influenza; Avian; Zoonosis; Adaptive changes; Cross-species transmission; Adaptation
• ISSN: 0264-410X; 1873-2518; 1873-2518
• DOI: 10.1016/j.vaccine.2012.04.049

► Pandemic influenza viruses all have their origins in animal reservoirs. ► Adaptive changes characterize animal influenza viruses crossing species barriers. ► These changes have been mapped to genetic mutations and specific adaptive pathways. ► These mutations and adaptive pathways are the subject of this review. Human influenza viruses have their ultimate origin in avian reservoirs and may adapt, either directly or after passage through another mammalian species, to circulate independently in the human population. Three sets of barriers must be crossed by a zoonotic influenza virus before it can become a human virus: animal-to-human transmission barriers; virus–cell interaction barriers; and human-to-human transmission barriers. Adaptive changes allowing zoonotic influenza viruses to cross these barriers have been studied extensively, generating key knowledge for improved pandemic preparedness. Most of these adaptive changes link acquired genetic alterations of the virus to specific adaptation mechanisms that can be screened for, both genetically and phenotypically, as part of zoonotic influenza virus surveillance programs. Human-to-human transmission barriers are only sporadically crossed by zoonotic influenza viruses, eventually triggering a worldwide influenza outbreak or pandemic. This is the most devastating consequence of influenza virus cross-species transmission. Progress has been made in identifying some of the determinants of influenza virus transmissibility. However, interdisciplinary research is needed to further characterize these ultimate barriers to the development of influenza pandemics, at both the level of the individual host and that of the population.