Co-infected plant hosts cause more severe epidemics

Plant hosts co-infected with more than one pathogen strain result in more severe epidemics than plants infected with only one strain. An article published in “Nature Communications” sums up what Branco Weiss fellow Pedro Vale and colleagues from the University of Helsinki found out about how co-infection alters population dynamics of infectious disease.

The work was carried out in collaboration with Anna-Liisa Laine and her research group at University of Helsinki, who have been studying the interaction between the host plant ribwort plantain, Plantago lanceolata, and its powdery mildew pathogen across hundreds of populations. The current study, recently published in the journal Nature Communications, found that co-infection by several strains of the same host plant are common in the wild with more than half of the host populations supporting co-infection.

Experimental work coupled with field surveys of infection found that host populations supporting co-infection suffer more severe epidemics than those where a single pathogen strain is present. A spore trapping experiment confirmed that the change in epidemiological dynamics is explained by the higher spore production rate of each individual host plant under co-infection.

These results confirm classic predictions of how infection dynamics can fundamentally change under co-infection. This work underlines the importance of understanding individual host variation in order to mitigate the severity and spread of infection. The study also highlights how important it is to account for co-infection – which can be spatially and temporally variable – when designing disease prevention efforts.

Article in “Nature Communications”