Modeling and analysis of a temperature-driven outbreak of waterfowl disease in the Upper Mississippi River

- An annual model for waterfowl disease in the Upper Mississippi River is proposed.
- Transmission relies on stochastic water temperatures gleaned from empirical studies.
- As annual average temperatures rise, infected host populations initially increase.
- Infected host populations decay after temperatures exceed a certain threshold.
- Increasing temperatures in the region may have a negative effect on parasites.

Bithynia tentaculata is an invasive snail that was discovered in the Upper Mississippi River (UMR) in 2002. In addition to being a threat to native benthos, the snail also harbors parasite associated with annual outbreaks of waterfowl mortality in the UMR. Trophic transmission of parasites between snails and birds occurs during seasonal waterfowl migrations, which can depend intimately on temperature. We developed an annual model for waterfowl disease in the UMR where transmission depends on water temperatures gleaned from empirical studies. By running simulations from annual temperature profiles selected randomly from a normal distribution, we quantified the association between the number of infected hosts and annual average temperatures. Model output demonstrated that as annual average temperatures rise, infected host populations initially increase and then decay after temperatures exceed a certain threshold. Results from this work suggest that increasing temperatures in the region may have a negative effect on parasites, decreasing their transmission and reducing infected host populations.

We developed an annual model for waterfowl disease (parasite life-cyle shown in (a)) in the Upper Mississippi River where transmission depends on water temperatures (transmission windows shown in (b)) gleaned from empirical studies. 167