1. Smithsonian National Zoo Conservation Biology Institute Global Health Program, , Washington DC 20008, USA
2. Mpala Research Centre , P.O Box 555-10400, Nanyuki, Kenya
3. Smithsonian National Zoo Conservation Biology Institute Center for Species Survival, , Front Royal, VA 22630, USA
4. Ol Jogi Wildlife Conservancy , P.O Box 259-10400, Nanyuki, Kenya