1. Arizona Department of Health Services, Office of Infectious Disease Services, Phoenix, Arizona.
2. Arizona Department of Health Services, Office of Border Health, Tucson, Arizona.
3. Pima County Health Department, Tucson, Arizona.
4. Santa Cruz County Health Department, Nogales, Arizona.
5. Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia.
6. Copper Queen Medical Associates, Douglas, Arizona.