Although it is known that chronic wasting disease (CWD) can be transmitted by both direct animal-to-animal contact and contact with contaminated environments, the relative role of each mechanism in the spread of CWD in free-ranging populations has yet to be defined. We investigated patterns of interaction between mule deer (Odocoileus hemionus) in order to understand how factors such as season and landscape may influence patterns of disease spread in these populations. Using location data from male and female Global Positioning System (GPS)-collared mule deer in 5 study areas located in and around a CWD-endemic zone in southern Saskatchewan, Canada, we quantified close proximity events, or events involving both spatial and temporal overlap of individuals. We defined close proximity events as occurrences in which 2 deer were located <25 m apart at the same point in time. We looked at seasonal variation in the probability of close proximity events, as well as landscape factors associated with these events when compared to areas of shared space use, or spatial overlap alone. Overall probability of an individual GPS-collared deer being located in close proximity to another GPS-collared deer was 0.092 (n = 107). The early gestation (16 Dec– 31 Mar) and late gestation (1 Apr–15 May) seasons had the highest probability of close proximity events occurring, and same-sex pairs were more likely to be found in close proximity than between-sex pairs during all seasons aside from the rut (1 Nov–15 Dec). High probability of close proximity events during the gestation seasons agrees with the tendency of mule deer to aggregate into large groups during late winter and suggests that this may be an important time period for CWD transmission to occur. Close proximity events occurred more in cropland and wetland than expected based on availability, whereas close proximity events occurred less than expected in grassland. The opposite was true for spatial overlap between individuals, which occurred more than expected in areas of low elevation and rugged terrain and in grassland or shrub-wood habitats. These results suggest that cropland may be a higher risk habitat for direct and indirect CWD transmission between individuals and that, although coulees and other areas of rugged topography are less likely to be associated with close proximity events, those areas may be more likely to contain environmental contamination in CWD-affected areas due to common use by multiple deer.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.