What Are Rickettsial Diseases?

Rickettsial diseases are infections that you can get from some tick bites.

Ticks are tiny: Some are as small as a poppy seed. You may not even know you’ve been bitten by one, but the diseases they carry can make a big impact on your body.

Part of the same family as spiders and scorpions, ticks are arachnids, not insects. Your blood is their food. Instead of staying on the outside of your skin, they tunnel into it to eat and fill up on your blood.

Just because a tick bites you doesn’t mean you’ll get a disease. Depending on the kind of tick, they have to be attached to your body for a certain amount of time.

Of the 800 species of ticks in the world, less than 60 species transmit bacteria when they bite. One group of bacteria ticks carry is called rickettsiae. That’s why these tick-borne conditions are called rickettsial diseases.

But not all diseases that ticks carry are rickettsial. For instance, Lyme disease is caused by a different bacteria called Borrelia burgdorferi.

Rickettsiosis

The bite of a Gulf Coast tick causes this condition. It’s also called Rickettsia parkeri rickettsiosis. This is a form of spotted fever, which means it commonly causes a rash or “spots.” But rickettsiosis is less serious than Rocky Mountain spotted fever.

The two diseases share symptoms such as fever, headache, joint pain, and muscle aches. But with rickettsiosis, there’s usually a scab, or “eschar,” where the tick was attached. Doctors can treat it with the antibiotic doxycycline.

Anaplasmosis

If a black-legged tick, or western black-legged tick, bites a rodent infected with the rickettsial bacteria Anaplasma phagocytophilum, and then bites you, it can cause anaplasmosis.

The symptoms are usually mild. You may not feel anything at all, or you may have flu-like symptoms including fever and fatigue within a week or two of the tick bite.

Your doctor may do a blood test to be sure. Antibiotics are the usual treatment and help quickly.

Ehrlichiosis

Named for the white dot on her back, the female Lone Star tick can carry the bacteria that causes both ehrlichiosis (say “air-lick-e-o-sus”) and Ehrlichiosis ewingii infection. The only difference between these two is the strain of ehrlichia bacteria that’s involved.

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Despite its name, this tick doesn’t just live in Texas. It makes its home all around the Eastern and Southeastern U.S.

You might not have symptoms. But if you do, they’ll start a week to two after a Lone Star tick attaches to and feeds on you for 24 hours. You might have a headache, chills, nausea, joint pain, cough, or confusion.

If you feel any of these, see a doctor promptly for testing and antibiotic treatment. If untreated, this bacteria, which attacks white blood cells, can cause seizures; kidney, respiratory, or heart failure; and even coma.

If a Lone Star tick transmits disease to you, it can also cause you to become allergic to red meat. If you have a stuffy or runny nose, hives, sneezing, nausea, headaches, or trouble breathing after eating red meat, ask your doctor for a skin or blood test.

Rocky Mountain Spotted Fever

Unlike the other rickettsial diseases, Rocky Mountain spotted fever can do serious damage to your organs if it’s not treated quickly with antibiotics. It’s not contagious, but it can be fatal.

Three ticks -- the American dog tick, the brown dog tick, and the Rocky Mountain wood tick -- all carry and pass on the disease if they’re infected with it.

Common early symptoms include a bad headache, high fever, nausea, and pain in your muscles and joints. A few days later, you may see a rash around your wrists and ankles that spreads to your palms and soles. It’ll be red, but won’t itch. This is a telltale sign of Rocky Mountain Spotted Fever, but not everyone who has the disease gets it.

WebMD Medical Reference Reviewed by Carol DerSarkissian on June 19, 2018

Sources

SOURCES:

University of Michigan Biokids: “Arachnida.”

National Pest Management Association: “Tick Identification & Removal.”

British Columbia Centre for Disease Control: “Tick Bites & Disease.”

Mayo Clinic: “Slideshow: Guide to different tick special and the diseases they carry.”

Government of South Australia: Rickettsial infections – including symptoms, treatment and prevention.”

CDC: “Other Spotted Fever Group Rickettsioses.”

California Department of Public Health: “Human Granulocytic Anaplasmosis.”

CDC: “Anaplasmosis.”

California Department of Public Health: “Ehrlichiosis.”

CDC: “Tick-borne Diseases of the United States.”

Mayo Clinic: “Ehrlichiosis.”

American College of Allergy, Asthma & Immunology: “Red Meat Allergy.”

Mayo Clinic: “Rocky Mountain spotted fever.”

CDC: “Lyme Disease.”

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