Abstracts (first author)
Multiple-strain infections of Borrelia afzelii – a role for within-host interactions in the maintenance of antigenic diversity?
Competition is an important evolutionary force and is expected to be most severe between closely related species. In infectious diseases many infections consist of genetically distinct strain, suggesting that and competition between strains might be important. Signs of such competition have been observed in for example malaria infections. Here we investigated the occurrence of competition between closely related strains of the tick-borne disease Borrelia afzelii, one of the species causing Lyme disease in Europe, in one of their most important reservoir hosts, the bank vole (Myodes glareolus). We separated strains based on the highly polymorphic ospC gene using strain specific PCR primers, and found that infected voles on average harbored 2.5 different ospC types. The strains showed a highly aggregated distribution and there were surprisingly little indication of competition. The results rather indicates that strains have a positive effect on each other. Moreover, genetically more different strains were more often found together. In conclusion we suggest that positive interactions might help maintain strain diversity in B. afzelii and that competition between strains play a relatively minor role in this system.