[1] Univ Georgia, Inst Ecol, Athens, GA 30602 USA
[2] Commonwealth Sci Ind Res Org, Australian Anim Hlth Lab, Geelong, Vic, Australia
[3] James Cook Univ N Queensland, Sch Publ Hlth & Trop Med, Townsville, Qld 4811, Australia
[4] Zool Soc London, Inst Zool, London NW1 4RY, England
[5] US Geol Survey, Natl Wildlife Hlth Ctr, Madison, WI USA