Within-host competition between XXXX ospC strains in wild hosts as revealed by massively parallel amplicon sequencing.

@entity281 @entity21786 @entity325
@entity281 frequently consist of more than one strain of a given pathogen. Experiments have shown that co-infecting strains often compete, so that the @entity281 intensity of each strain in @entity325 is lower than in single strain infections. Such within-host competition can have important epidemiological and evolutionary consequences. However, the extent of competition has rarely been investigated in wild, naturally infected hosts, where there is noise in the form of varying inoculation doses, @entity281 and host heterogeneity, which can potentially alleviate or eliminate competition. Here, we investigated the extent of competition between @entity21786 strains (as determined by ospC genotype) in three host species sampled in the wild. For this purpose, we developed a protocol for 454 amplicon sequencing of ospC, which allows both detection and quantification of each individual strain in an @entity281 . Each host individual was infected with one to six ospC strains. The @entity281 intensity of each strain was lower in @entity325 than in single ones, showing that there was competition. Rank-abundance plots revealed that there was typically one dominant strain, but that the evenness of the relative @entity281 intensity of the different strains in an @entity281 increased with the multiplicity of @entity281 . We conclude that within-host competition can play an important role under natural conditions despite many potential sources of noise, and that quantification by next-generation amplicon sequencing offers new possibilities to dissect within-host interactions in naturally infected hosts.
