• Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, is found in North America and South America. The main vectors are the ticks Dermacentor andersoni, Dermacentor variabilis, Rhiphicephalus sanguineus, Amblyomma americanum and Amblyomma cajennense. (B47)
• Rickettsias are apparently well-established parasites of arthropods, which appear also to be well-adapted to mammals, particularly rodents and other small mammals; these may provide a reservoir of infection. (B47)
• The organisms are probably maintained in a variety of mammalian hosts (field mice, rabbits, sheep, dogs etc.); the western form is known also to be transmitted from adult ticks to their progeny. (B47)

• This rickettsial disease of humans is transmitted by ticks, particularly Dermacentor andersoni, the Rocky Mountain wood tick. (B47)
• Infection in ticks is common; infection in humans is incidental. (B47)

In Humans

• Fever, rash or dark blotches (due to blood vessel lesions) and nervous signs. (B47)
• There appear to be three forms: 
  • The eastern form, transmitted by Dermacentor variabilis, the dog tick, is less often fatal;
  • The western form, seen in the Rocky Mountain area and transmitted by Dermacentor andersoni, the sheep tick, is more often fatal;
  • The Brazilian form, also known as Sao Paulo typhus, is transmitted by Amblyomma cajennense.

  (B47)

• The main hosts are wild mammals, particularly rodents, also dogs and birds. (B47)

In Bears

• Antibodies to Rocky Mountain Spotted Fever were detected by complement fixation test in 6/282 sera (2%) from 265 Ursus americanus - American black bear from northcentral Idaho, 1971-1975. (J1.16.w12)

• History & Documentation
• Physical Examination of Mammals
• Necropsy of Mammals
• Environmental Assessment
• Treatment and Care
• Environmental and Population Management
• Chapter 2 - B36 Field Manual of Wildlife Diseases - Specimen Collection and Preservation
• Chapter 3 - B36 Field Manual of Wildlife Diseases - Specimen shipment
• Appendix A - B36 Field Manual of Wildlife Diseases - Sample specimen history form

• Bears (Ursidae - Bears (Family))
• Ursus americanus - American black bear

(List does not contain all other species groups affected by this infectious agent)