Dr. Barbara Milutinovic (IST Austria)
in: 'Frontiers in Ecology and Evolution': "Social immunity modulates competition between coinfecting pathogens"
by Dr. Barbara Milutinovic (IST Austria)
Coinfections of hosts with multiple pathogens are common, and can result in complex within-host dynamics resulting in altered virulence and transmission outcomes. Whilst multiple infections are intensively studied in solitary hosts, it is so far unresolved how interactions within groups of social hosts can interfere with pathogen competition, and if this depends on coinfection diversity. We studied how the social immunity of ants – their collective disease defenses – influence pathogen competition in coinfections using strains of same or different fungal pathogen species. We found that social immunity modulated pathogen transmission, by giving advantage to one species over the other. This resulted in increased co-sporulation on individual cadavers and a higher pathogen diversity at the community-level. Mathematical modeling revealed that host sanitary care alone can modulate competitive outcomes between pathogens, giving advantage to fast-germinating, thus less grooming-sensitive ones. Host social interactions can hence modulate infection dynamics in coinfected group members, thereby altering pathogen communities at the host- and population-level.