The impact of within-host coinfection interactions on between-host parasite transmission dynamics varies with spatial scale

Within-host interactions among coinfecting parasites can have major consequences for individual infection risk and disease severity. However, the impact of these within-host interactions on between-host parasite transmission, and the spatial scales over which they occur, remain unknown. We developed and applied a novel spatially explicit analysis to parasite infection data from a wild wood mouse (Apodemus sylvaticus) population. We previously demonstrated a strong within-host negative interaction between two wood mouse gastrointestinal parasites, the nematode Heligmosomoides polygyrus, and the coccidian Eimeria hungaryensis, using drug-treatment experiments. Here, we show this negative within-host interaction can significantly alter the between-host transmission dynamics of E. hungaryensis, but only within spatially-restricted neighbourhoods around each host. However, for the closely related species E. apionodes, which experiments show does not interact strongly with H. polygyrus, we di..., , , # The impact of within-host coinfection interactions on between-host parasite transmission dynamics varies with spatial scale 🦠 🗺️

# **Overview 📄**

These data were collected in 2012 as part of a broader piece of work exploring the parasite communities of the wood mouse (*Apodemus sylvaticus*). This code base takes input data from trapping grids and calculates neighbourhood prevalence relative to each individual on the grid. It does this by iteratively identifying each individual in the population as the ‘focal’ individual, and each other as a potential neighbour, with a distance to the focal individual calculated. Then neighbourhood prevalence and mean infection burden of the potentially interacting parasite (the nematode *Heligmosomoides polygyrus*) are calculated for each user-defined neighbourhood size around the focal individual. These are then able to be used in statistical models as an explanatory factor for the specified infection state (*Eimeria* presence/absence or intensity)...