infections
Rocky Mountain Spotted Fever (RMSF)
Introduction
Rocky Mountain spotted fever is a potentially fatal Overview of Rickettsial Infections that is transmitted by dog ticks and wood ticks. It causes a rash, headache, and high fever. People become infected when a tick carrying the infection bites them. A severe headache, chills, extreme exhaustion, and muscle pains develop, usually followed a few days later by a rash. People are given antibiotics immediately if they have been bitten by a tick and have typical symptoms. Avoiding tick bites is the best way to prevent the infection. . Overview of Rickettsial Infections are a type of bacteria that can live only inside the cells of other organisms. Rocky Mountain spotted fever is probably the most common rickettsial infection in the United States. It was first recognized in the Rocky Mountain states but occurs throughout most of the continental United States. It is most common in the southeastern and south central United States (North Carolina, Oklahoma, Arkansas, Tennessee, and Missouri). It also occurs in Central and South America. Rocky Mountain spotted fever occurs mainly from March to September, when adult ticks are active and people are likely to be in tick-infested areas. In the southern states, the disease may occur throughout the year. The infection is more common among people who spend a lot of time in tick-infested areas and among children younger than 15. Ticks acquire these rickettsiae by feeding on infected mammals, typically rodents. Infected female ticks can also transmit rickettsiae to their offspring. Infection is spread to people through bites by wood ticks or dog ticks. Rickettsial infection is probably not transmitted directly from person to person. Rickettsiae live and multiply in the cells lining blood vessels. Blood vessels in and under the skin and in the brain, lungs, heart, kidneys, liver, and spleen are commonly infected. Small infected blood vessels may become blocked by blood clots. Many people with Rocky Mountain spotted fever symptoms do not remember having a tick bite. 