[1] Univ Edinburgh, Royal Dick Sch Vet Studies, Wildlife & Emerging Dis Sect, Roslin EH25 9RG, Midlothian, Scotland
[2] WHO, Dept Food Safety Zoonoses & Foodborne Dis, CH-1211 Geneva 27, Switzerland
[3] Ctr Dis Control & Prevent, Int Emerging Infect Program, Nairobi, Kenya