This illustration depicts a dorsal view of a female “hard”, or Ixodidae “American dog tick”, Dermacentor variabilis.

The two major vectors of Rickettsia rickettsii, the bacteria responsible for Rocky Mountain spotted fever in the United States are the American dog tick, Dermacentor variabilis, pictured here, and the Rocky Mountain wood tick D. andersoni.

Content Providers(s): CDC/ Andrew J. Brooks

Picture & text from CDC/PHIL. For more information on source & for information on color coding used above for different types of ticks, see Tick Pictures from CDC