By definition, contact denotes the junction of at least two objects. In the context of disease transmission, contact implies interaction with potential to spread disease. Mischaracterization of contacts may result in inaccurate estimates of transmission rates. To collect more-accurate contact data among white-tailed deer (Odocoileus virginianus), we built a deer-borne contact detection system (DCDS) consisting of a camera and a proximity logger installed on a GPS (Global Positioning System) collar. We outfitted 26 adult male deer with DCDSs to record GPS locations, proximity of equipped deer to other equipped deer, and video of deer interactions in southern Texas during autumn 2010. From 17 continuously functional DCDSs, we documented 33 contacts with cameras, 61 with proximity loggers, and 16 with GPS, resulting in estimated mean daily contact rates of 0.29, 0.66, and 0.12, respectively. Cameras and GPS underrepresented contacts among deer, whereas proximity loggers provided credible estimates for epidemiological modeling.
