A major question regarding the ecology of infectious diseases is the role of the host in pathogen transmission dynamics. Avian hosts vary greatly in their susceptibility to avian influenza virus (AIV) infection and thus differentially contribute to its maintenance and transmission. Epidemiological investigations of AIV outbreaks coupled with infection trials in waterbird hosts provide important parameters for the formulation of transmission models, but do not establish a mechanistic basis for variation of these parameters. A gatekeeper for effective AIV infection that is conserved across vertebrate taxa is the specific linkage of sialic acid (Sia) to cell membrane glycoproteins. For example, human influenza virions most efficiently gain access to cells expressing Sia linked to glycoproteins in a 2-6-α−galactose (2-6) configuration whereas AI virions mainly enter cells expressing a 2-3-α−galactose (2-3) linkage. Therefore, we have begun to characterize the phylogenetic variability of the ratio between 2-6 and 2-3 linkage types expressed on gastrointestinal and respiratory membranes on five avian species that vary in their susceptibility to avian influenza infection and to determine if red blood cell (RBC) membranes might provide a non-lethal index for this variation.
Results/Conclusions
We have found that rock pigeons (Columba livia) collected in Nambe, New Mexico express μg total Sia / ml RBCs and that the mass spectrometric technique we have developed is suitable for high-throughput Sia characterization in wild birds. These data will be used to build a phylogenetic guide map to predict avian influenza host range. Population biology dynamics will then be applied to the phylogenic species range map for wild avian communities for their importance of the propagation of AIV.
