PARENT SESSION
Wednesday, August 9, 1:30-5:00 pm
COS 69 - Disease ecology IV: transmission and land use
L-4, Lobby Level, Cook Convention Center
Presiders: J Brunner and A Radomski
Contact rates among white-tailed deer in southern Illinois: effects of group membership, time, and space.
Schauber, Eric*,1, Kjaer, Lene1, Storm, Daniel1, 2, Nielsen, Clayton1, 1 Cooperative Wildlife Research Laboratory, Carbondale, IL, USA2 Department of Wildlife Ecology, Madison, WI, USA
ABSTRACT- Infectious diseases can be spread through direct or indirect (e.g., by environmental contamination or vectors) contact. Some, like chronic wasting disease in deer and elk, are poorly understood in terms of their mode of transmission and factors affecting contact rate. We used global positioning system collars to assess direct and indirect contact rates among a total 29 white-tailed deer ranging from October 2002 to February 2006. Based on logistic regression analysis, the estimated odds of direct contact during fall were 22-fold (95% CI: 4 to 121-fold) higher for pairs of deer in the same social group than for between-group pairs, after accounting for joint space use. Group membership had smaller effects on indirect contacts (estimated odds ratio = 4.7 for 1-day time lag, 2.1 for 30-day time lag). Contact rates in summer were lower than in fall and showed no effect of group membership. Direct contact rates both within and between groups showed minor diel fluctuations, with between-group contacts lowest around sunrise and within-group contacts lowest in the afternoon. Between-group contacts tended to occur in bedding areas and around concentrated food sources, with some clusters associated bait piles for deer capture. Our results imply that directly transmitted diseases are likely to spread much more quickly within than between social groups of deer, but group membership has less of an effect on indirect contacts even with a short time lag. Also, contacts do not appear to be associated with particular times of day or behavioral states. However, direct and indirect contacts among deer may be increased in the vicinity of concentrated food sources.
Key words: disease transmission, disease ecology, GPS telemetry