COS 262-4 - Do infected parents produce infection-resistant offspring? Evidence for transgenerational immune priming in a guppy host-parasite system

Background/Question/Methods

Transgenerational immune priming (TGIP) is a phenomenon in which parental infection with a parasite or pathogen improves the ability of their offspring to resist infection. TGIP has been described in a variety of taxa across both invertebrates and vertebrates but has not been extensively investigated in the context of infectious disease dynamics. We used the Trinidadian guppy (Poecilia reticulata) and Gyrodactylus turnbulli host-parasite system to investigate the role TGIP may play in host resistance, and test whether TGIP depends on which parent experienced infection. We hypothesize that guppies of parents that have never been exposed to G. turnbulli infection will experience a higher parasite load than guppies with parents that had been experimentally infected and treated for infection. To test this hypothesis, we isolated and infected offspring from pairs of guppies with a known infection history: either the mother, the father, or neither parent had been experimentally infected with G. turnbulli and then cleared of infection. We recorded the parasite load of 40 offspring from 12 breeding pairs over a period of 15 days.

Results/Conclusions

Offspring from naïve fish appeared to carry significantly higher parasite loads than those from previously infected fish. Notably, there was also significantly more variance in parasite load for fish from naïve parents. These results did not depend on whether the mother or the father had been infected, suggesting that there is a more complex mechanism of passing along immune system information than exposure to the maternal environment. Our results provide more evidence for TGIP in a host-parasite system, which could be used to control parasite outbreaks in places such as aquaculture facilities or natural populations of conservation concern. Future work could investigate the connections between TGIP and other mediators of parasite transmission, such as behavioral variation and microbiome composition, to develop a more complete understanding of infectious disease dynamics.