Giuseppe
Emeritus
[Source: Epidemics, full text: (LINK). Abstract, edited.]
full pdf available on line at this link: http://origem.info/FIC/pdf/Roche_Rohani_Env_trans_scrambles_coex_patterns_AIVs_Epidemics_Jun10.pdf
Epidemics
Volume 2, Issue 2, June 2010, Pages 92-98
doi:10.1016/j.epidem.2010.03.002
Environmental transmission scrambles coexistence patterns of avian influenza viruses
Benjamin Roche<sup>a</sup>, Pejman Rohani<sup>a</sup><sup>, </sup><sup>b</sup><sup>, </sup><sup>c</sup>
<sup>a) </sup>Department of Ecology & Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
<sup>b) </sup>Center for the Study of Complex Systems, University of Michigan, Ann Arbor, MI 48109, USA
<sup>c) </sup>Fogarty International Center, National Institutes of Health, Bethesda, MD 20892, USA
Received 22 January 2010; revised 16 March 2010; Accepted 16 March 2010. Available online 29 March 2010.
Abstract
Despite the recent accumulation of theoretical and empirical studies on avian influenza viruses (AIVs), the interactions among the diverse pool of strains remain poorly understood. One potential reason is multiple transmission routes. In this paper, we explore the behavior of a two-strain mathematical model of AIV dynamics with lifelong immunity to understand how the combination of direct and environmental transmission (via a persistent viral reservoir) determines strains coexistence and dominance. We find that coexistence requires the magnitude of basic reproductive ratios of the strains to be identical for each transmission route (R<sub>0</sub><sup>dir</sup> and R<sub>0</sub><sup>env</sup>) when cross-immunity is assumed to be perfect. Coexistence may be also possible when one strain is only directly transmitted and the contribution by environmental transmission is high. When we relax this assumption, the level of cross-protection does not modify coexistence criteria when strains are mainly environmentally transmitted, in contrast to the case where direct transmission dominates. Finally, when competitive exclusion is observed, the strain with the largest contribution from direct transmission outcompetes the other through competition for viral particle acquisition. Overall, we conclude that environmental transmission can affect the patterns of coexistence predicted by direct transmission models in complex ways.
Keywords: Avian influenza; Strain competition; Mathematical modeling
- ------Volume 2, Issue 2, June 2010, Pages 92-98
doi:10.1016/j.epidem.2010.03.002
Environmental transmission scrambles coexistence patterns of avian influenza viruses
Benjamin Roche<sup>a</sup>, Pejman Rohani<sup>a</sup><sup>, </sup><sup>b</sup><sup>, </sup><sup>c</sup>
<sup>a) </sup>Department of Ecology & Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
<sup>b) </sup>Center for the Study of Complex Systems, University of Michigan, Ann Arbor, MI 48109, USA
<sup>c) </sup>Fogarty International Center, National Institutes of Health, Bethesda, MD 20892, USA
Received 22 January 2010; revised 16 March 2010; Accepted 16 March 2010. Available online 29 March 2010.
Abstract
Despite the recent accumulation of theoretical and empirical studies on avian influenza viruses (AIVs), the interactions among the diverse pool of strains remain poorly understood. One potential reason is multiple transmission routes. In this paper, we explore the behavior of a two-strain mathematical model of AIV dynamics with lifelong immunity to understand how the combination of direct and environmental transmission (via a persistent viral reservoir) determines strains coexistence and dominance. We find that coexistence requires the magnitude of basic reproductive ratios of the strains to be identical for each transmission route (R<sub>0</sub><sup>dir</sup> and R<sub>0</sub><sup>env</sup>) when cross-immunity is assumed to be perfect. Coexistence may be also possible when one strain is only directly transmitted and the contribution by environmental transmission is high. When we relax this assumption, the level of cross-protection does not modify coexistence criteria when strains are mainly environmentally transmitted, in contrast to the case where direct transmission dominates. Finally, when competitive exclusion is observed, the strain with the largest contribution from direct transmission outcompetes the other through competition for viral particle acquisition. Overall, we conclude that environmental transmission can affect the patterns of coexistence predicted by direct transmission models in complex ways.
Keywords: Avian influenza; Strain competition; Mathematical modeling
full pdf available on line at this link: http://origem.info/FIC/pdf/Roche_Rohani_Env_trans_scrambles_coex_patterns_AIVs_Epidemics_Jun10.pdf
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