Small rodent in a gloved hand

Janine Mistrick

Research Q & A

How did you get started/what drew you to your area of study?

I love the spatial aspects of ecology – how variation in the environment through plant species, geography, climate creates heterogeneity across a landscape and how that affects the animals that live there. Adding in disease as an interaction between those animals and their environment is just another layer of complexity that makes everything that much more interesting! Broadly, I want to use my research to address questions such as: How are the patterns of disease we see in nature affected by the place where we’re studying them? For instance, what aspects of the environment can cause patterns of infection to be different in region A compared to that same host species and disease in region B?

Where are you working on research/field work?

My fieldwork takes place in southern Finland near a town called Lammi – our field sites are scattered about the surrounding region in forested areas with mature spruce stands. The Lammi region is about 2 hours north of Helsinki in the central part of the country. Our research team (a U.S.-based team) is collaborating with the University of Helsinki and so our in-country support is provided by researchers at the University of Helsinki and our ‘home base’ for our fieldwork is a biological field station in Lammi operated by the University of Helsinki.

What are you currently working on?

Our field study is investigating the effects of habitat quality and coinfection (a host infected with multiple parasites at once – e.g., both intestinal worms and a respiratory virus) on prevalence of a naturally circulating viral pathogen in a wild rodent species. Specifically, our study is investigating how food addition and removal of intestinal worm parasites affects the prevalence of a hantavirus in wild bank voles (a small rodent, much like a mouse). To investigate these effects, we’re studying bank voles in their natural habitat at several different forest sites. At some of our study sites, we’re throwing out extra food for the voles (sunflower seeds and mouse chow pellets) every two weeks, and at other sites we’re treating the voles with an oral de-wormer (a medication like you’d give a dog or cat) to remove any intestinal parasites they might have, and then a third group of sites are controls where we don’t do either treatment. We’re monitoring the populations and collecting samples at all the sites so we can compare how our treatments affect the populations and the prevalence of the viral pathogen. I spent the spring and summer of 2021 at our field sites in Finland live-trapping wild voles and recording the space-use of individual voles based on their capture locations in a grid of traps set up at each of our forest study sites. We also collected data on vole body size and reproductive status and took blood and fecal samples to test for viral infection.

How are you working toward that goal?

Back at the University of Minnesota, I’m using computer software (Program R and specific ‘packages’ designed for building and analyzing networks) to build networks representing how individual voles overlapped in their observed locations on our grids. I’ll be comparing these “spatial overlap” networks between our different study sites to determine how our experimental treatments (food addition and deworming treatment of captured animals to remove intestinal parasites) affect spatial overlap between individual voles. I’m hoping to find significant difference in network structure and how much voles overlapped on our treated sites (compared to the control sites) to suggest that our treatments influence how voles use their environment and could increase their opportunities for interacting and spreading diseases within their populations.

What will your next steps/research be?

Once I’ve established general patterns of spatial overlap related to the treatments (and once our lab team has had time to complete the viral testing on all of our 2021 samples to determine which animals were infected) – then I plan to combine the data on which animals were infected with how they were connected in the spatial overlap networks I developed to understand how the spatial overlap between animals might be influencing transmission of the virus within the vole populations (much like contact tracing with humans and COVID-19!).


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