Ecology and Evolution of Disease Interference

University Of Georgia Research Foundation Inc, Athens GA

Investigators

Abstract

The proposed work will develop a general framework for the ecological and evolutionary dynamics of "disease communities". Surprisingly, the possible interaction between unrelated infections has not received much attention. A mechanism for interaction between (antigenically) different infections is proposed: following an acute infection, individuals are temporarily unavailable to contract other diseases (because of quarantining during convalescence). Hence, the number of potential "hosts" for a pathogen is affected by the dynamics of other diseases; this is even more pronounced if infection is associated with mortality, with some hosts removed permanently. This mechanism leads to "disease interference". This proposal aims to develop this framework, answering fundamental ecological and evolutionary questions. Do all infections interact with all other infections? The answer is clearly no. The strength of interaction between infections depends on the degree similarity in the cohort of hosts infected. For human infections, this would be determined by the overlap between the distributions of host age at infection. Does interference affect evolutionary dynamics? A central hypothesis is that interference selects for increased pathogenicity. Can we explore interference effects when genetic diversity is well established (eg Dengue)? The interference mechanism provides a null model for the study of infections with multiple strains. Is this work likely to have public health implications? Preliminary work suggests interference effects may be beneficially used to eradicate infections using fewer vaccine units than conventional estimates. This proposal also aims to construct statistical tools whereby the signature of interference may be confidently detected from data.