Rocky Mountain spotted fever is an acute febrile disease of the the Americas. In addition to humans, other mammalian hosts include dogs, rodents, and other small animals. The causal organism is Rickettsia rickettsii. The disease is transmitted by ticks that feed on infected animals. Mortality rate varies, averaging about 20%, but as high as 40% in cases where it is not identified and appropriately treated with antibiotics; it is low in children and high in adults.
In the USA in 1988, there was a 3 percent fatality rate of the 700 reported cases of Rocky Mountain spotted fever.