Tweet
Inactivation of Influenza A Viruses in the Environment and Modes of Transmission: A Critical Review - ECDC Health Content
Inactivation of Influenza A Viruses in the Environment and Modes of Transmission: A Critical Review
Thomas P. Weber, Nikolaos I. Stilianakis. - Inactivation of Influenza A Viruses in the Environment and Modes of Transmission: A Critical Review. J Infect. 2008 Nov; 57(5):361-73.
Description:
This review covers related but wide-ranging topics of influenza virus structure and biochemical characteristics, influenza virus persistence in the environment, influenza virus inactivation and influenza virus infection modes of transmission.
To review the knowledge of quantitative and qualitative inactivation of human influenza A viruses, the authors identified relevant articles through Medline and Science Citation Index and book chapters as well as references provided in articles.
The search strategy for information on modes of transmission and other topics is unstated.
For virus found in aerosols, the authors describe the impact of relative humidity and temperature (contradictory results), UV radiation (efficient under certain conditions), and open air factor (speculative with data only from other viruses).
The data from studies in these areas can be extrapolated to suggest that indoor transmission via an airborne route is plausible.
Inactivation of virus on animate and inanimate surfaces is described, focusing on hands, nasal mucus (strong survival enhancing effect), and surfaces (survival inversely proportional with porosity of the material).
Virus survival and transmission through water is discussed extensively, according to the authors, because of the recently increased attention given to highly pathogenic avian influenza virus H5N1 and its presence in wild and domesticated aquatic birds.
The persistence of different avian influenza viruses in open water and the effect of salinity and temperature are discussed.
Whether these factors allow for a reservoir that would have an impact on transmission and pandemic potential remains unknown.
The authors? conclude that the relative contribution for influenza transmission among the droplet, airborne and contact routes cannot be quantified.
The studies to answer this question have not been done because of lack of perceived threat from influenza (until recently), methodological problems studying transmission, and incomplete knowledge of factors affecting transmission as well as a lack of interdisciplinary communication.
ECDC Comment (03/02/2009):
This article provides a compact review of essential issues in influenza transmission, focusing on aspects of viral characteristics and environmental effects. The connection between the mode of transmission and the susceptibility of the virus to environmental factors (enhancing or blocking transmission) makes the lack of knowledge about specific modes of transmission and their relative contribution an enormous stumbling block toward designing effective interventions to prevent the spread of disease (other than immunization). In addition, as the authors indicate, human behavioural factors can undermine the effectiveness of any intervention (e.g., incorrect use, expense, non-adherence).
Although proverbial for most scientific reviews, the authors correctly state that ?further empirical and theoretical research on the transmission pathways of influenza viruses? is needed.
A view echoed by earlier.(1) by Towards this end, the European Commission has announced funds for efficacy and effectiveness of personal protection equipment and other measures against influenza transmission (2).
This call for proposals recognizes the same inseparableness of transmission modes and effective interventions.
The relative importance of one mode of transmission may be proved indirectly by demonstrating the effectiveness of an intervention designed to protect against that mode of transmission and vice versa.
The announcement also allows for study of the human factors that could undermine even the most evidence-laden intervention.
* Influenza team (ECDC). Influenza transmission: research needs for informing infection control policies and practice. Euro Surveill. 2007;12(19):pii=3189. Available online: http://www.eurosurveillance.org/View...ArticleId=3189
* European Commission, in the FP7 Cooperation Work Programme: Health, announced funds for ?Efficacy and effectiveness of personal protection equipment and other measures against influenza transmission?.
-
<cite cite="http://ecdc.europa.eu/en/health_content/sciadv/090205_sciadv.aspx">ECDC Health Content</cite>
Thomas P. Weber, Nikolaos I. Stilianakis. - Inactivation of Influenza A Viruses in the Environment and Modes of Transmission: A Critical Review. J Infect. 2008 Nov; 57(5):361-73.
Description:
This review covers related but wide-ranging topics of influenza virus structure and biochemical characteristics, influenza virus persistence in the environment, influenza virus inactivation and influenza virus infection modes of transmission.
To review the knowledge of quantitative and qualitative inactivation of human influenza A viruses, the authors identified relevant articles through Medline and Science Citation Index and book chapters as well as references provided in articles.
The search strategy for information on modes of transmission and other topics is unstated.
For virus found in aerosols, the authors describe the impact of relative humidity and temperature (contradictory results), UV radiation (efficient under certain conditions), and open air factor (speculative with data only from other viruses).
The data from studies in these areas can be extrapolated to suggest that indoor transmission via an airborne route is plausible.
Inactivation of virus on animate and inanimate surfaces is described, focusing on hands, nasal mucus (strong survival enhancing effect), and surfaces (survival inversely proportional with porosity of the material).
Virus survival and transmission through water is discussed extensively, according to the authors, because of the recently increased attention given to highly pathogenic avian influenza virus H5N1 and its presence in wild and domesticated aquatic birds.
The persistence of different avian influenza viruses in open water and the effect of salinity and temperature are discussed.
Whether these factors allow for a reservoir that would have an impact on transmission and pandemic potential remains unknown.
The authors? conclude that the relative contribution for influenza transmission among the droplet, airborne and contact routes cannot be quantified.
The studies to answer this question have not been done because of lack of perceived threat from influenza (until recently), methodological problems studying transmission, and incomplete knowledge of factors affecting transmission as well as a lack of interdisciplinary communication.
ECDC Comment (03/02/2009):
This article provides a compact review of essential issues in influenza transmission, focusing on aspects of viral characteristics and environmental effects. The connection between the mode of transmission and the susceptibility of the virus to environmental factors (enhancing or blocking transmission) makes the lack of knowledge about specific modes of transmission and their relative contribution an enormous stumbling block toward designing effective interventions to prevent the spread of disease (other than immunization). In addition, as the authors indicate, human behavioural factors can undermine the effectiveness of any intervention (e.g., incorrect use, expense, non-adherence).
Although proverbial for most scientific reviews, the authors correctly state that ?further empirical and theoretical research on the transmission pathways of influenza viruses? is needed.
A view echoed by earlier.(1) by Towards this end, the European Commission has announced funds for efficacy and effectiveness of personal protection equipment and other measures against influenza transmission (2).
This call for proposals recognizes the same inseparableness of transmission modes and effective interventions.
The relative importance of one mode of transmission may be proved indirectly by demonstrating the effectiveness of an intervention designed to protect against that mode of transmission and vice versa.
The announcement also allows for study of the human factors that could undermine even the most evidence-laden intervention.
* Influenza team (ECDC). Influenza transmission: research needs for informing infection control policies and practice. Euro Surveill. 2007;12(19):pii=3189. Available online: http://www.eurosurveillance.org/View...ArticleId=3189
* European Commission, in the FP7 Cooperation Work Programme: Health, announced funds for ?Efficacy and effectiveness of personal protection equipment and other measures against influenza transmission?.
-
Comment