Rocky Mountain spotted fever is an extremely nasty infectious disease caused by the
bacterium Rickettsia rickettsii, and generally spread by
ticks.
Rickettsia is named after
Howard T. Ricketts, discoverer of the disease's bacterial origin, and its apparent nomenclatural similarity to the vitamin deficiency disease
rickets is entirely coincidental.
The disease was first recognized in Idaho in 1895. Originally known as "black measles,"
it received its current name from Ricketts' Rocky Mountain Laboratory in Montana. Before the widespread adoption of tetracycline antibiotics to treat it, Rocky Mountain spotted fever was a veritable plague, with mortality rates as high as 30 percent and many survivors crippled for life. Even with antibiotic treatment, it remains so virulent that about 5 percent of cases are still fatal.
It is in no way confined to the Rocky Mountains. Cases have been reported in every U.S. state except Alaska, Hawaii, Maine and Vermont, as well as southern Canada, Mexico, Central America and parts of South America. Fortunately, you can't catch it from another person, so there is no danger in contact with someone afflicted by this disease. You might, however, get it indirectly from a dog if an infected tick jumps off of it and bites you. If you notice and remove it immediately, you'll probably be all right, as the tick usually has to spend several hours draining your succulent flesh before transmission occurs. Be careful when grooming your pet, too - you can catch RMSF from the blood or feces (ewww!) of a dead tick. The best way to avoid contracting RMSF is just to stay away from tick-infested areas, and use a repellent if you must traverse them. Types of tick known to carry the disease in North America include the wood tick, the dog tick, and the Lone Star tick. (that last one would be an excellent name for a comic book character!)
Rocky Mountain spotted fever is most common in children under 15 years of age, and is more common in males than in females. It's unlikely there's a physiological basis for this trend; boys playing in the dirt simply have a greater opportunity to get bitten by ticks. Its incubation period can range from a few days to approximately two weeks after the bite. Initial symptoms are high fever, severe headache, sharp muscle pains, nausea and vomiting. These symptoms are common to many illnesses, however, which makes diagnosis of RMSF difficult at times. A few days after the onset of fever, the disease's characteristic rash appears, starting on the limbs and spreading rapidly. Those who wait until this later stage of the disease's development to begin treatment are far more likely to die from it.
To complicate matters, the rash doesn't always appear. The only certain way to diagnose Rocky Mountain spotted fever is through a blood test, which can take several days to produce results, particularly in the rural areas where the disease is most common. Therefore, the most prudent plan is to treat any suspected case as if it were RMSF, rather than take the further risk of delaying treatment while awaiting test results. When it occurs, death is usually caused by kidney failure.