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What is ehrlichiosis?

Ehrlichiosis (say err-lick-ee-o-sis) is a bacterial infection you can get from ticks. The ticks that spread ehrlichiosis are the Lone Star tick, the deer tick and the dog tick.

It has been known for many years that dogs, cattle and other animals can get ehrlichiosis. Now it’s known that ehrlichiosis can occur in humans as well. This infection was first found in humans in the mid-1980s.

Is ehrlichiosis found all over the United States?

Ehrlichiosis can occur in almost any area of the United States (especially in the southeastern and south central areas of the country), as well as in many foreign countries.


What are the symptoms of ehrlichiosis?

The symptoms of ehrlichiosis are like the symptoms of the flu. Symptoms usually begin 1 to 2 weeks after you’ve been bitten by an infected tick, but they may take up to 1 month to appear. You might have the following symptoms:

  • Fever
  • Chills
  • Fatigue
  • Malaise (a general feeling of not being well)
  • Headache
  • Joint and muscle aches
  • Nausea
  • Vomiting
  • Diarrhea
  • Confusion
  • Rash (this symptom is more common in children who have ehrlichiosis)

Most cases of ehrlichiosis are very mild. Some people who have ehrlichiosis do not develop symptoms and their bodies fight off the infection without treatment.

However, ehrlichiosis can become serious if the infection isn’t caught in the early stages. Symptoms of a more serious case of ehrlichiosis include:

  • Seizures
  • Difficulty breathing
  • Coma
  • Kidney failure

Because ehrlichiosis feels like the flu at first, it’s very important to see your doctor if you feel like you have the flu a few days to a few weeks after you’ve been bitten by a tick. Be sure to tell your doctor that you were bitten by a tick and when it happened. If you know what kind of tick bit you, be sure to give your doctor that information, also.

Causes & Risk Factors

Who gets ehlichiosis?

People who spend time in areas where ticks are common (either for work or recreation) are at higher risk of getting ehrlichiosis. Ticks usually wait near the top of grassy plants and low bushes for people or animals to brush up against their perch. Ticks will often crawl upward on people’s clothes or bodies for up to several hours or more before attaching to the skin.

Diagnosis & Tests

How can my doctor tell if I have ehrlichiosis?

Your family doctor will perform blood tests to diagnose ehrlichiosis.


How can I prevent tick-borne diseases?

The best way to prevent tick-borne diseases is to avoid being bitten by ticks. When you are outdoors, follow these guidelines:

  1. Use tick repellents according to their instructions to help prevent bites. Use an insect repellent containing 20% to 30% DEET. Tick repellents that contain DEET can be put directly on your skin or on your clothing before going into tick-infested areas. Apply DEET sparingly to skin according to directions on the label. Don’t apply it to the face and hands of children and don’t use it on infants younger than 2 months of age. Repellents containing permethrin should be put only on clothing. Make sure to talk to your doctor before you use any tick repellent on your child. Your doctor can give you more information on what type and strength of repellent is safe to use.
  2. Wear light-colored clothing that covers most of your skin when you go into the woods or an area overgrown with grass and bushes. This makes it easier to see and remove ticks from your clothing. Wear a long-sleeved shirt and wear pants instead of shorts. Tuck your pant legs into your socks or boots for added protection. Remember that ticks are usually found close to the ground, especially in moist, shaded areas. Check your entire body for ticks after you have been in tick-infested areas, and check your children and pets for ticks. Common tick bite locations include the back of the knees, groin area, underarms, ears, scalp and the back of the neck.
  3. Remove any attached ticks as soon as possible. To remove an attached tick, use fine tweezers to grab the tick firmly by the head (or as close to the head as possible) and pull. Do not use heat (such as a lit match), petroleum jelly or other methods to try to make the tick “back out” on its own. These are not effective ways to remove a tick.
  4. Wash the area where the tick was attached thoroughly with soap and water. Keep an eye on the area for a few weeks and note any changes. You should call your doctor if you develop a rash around the area where the tick was attached. Be sure to tell your doctor that you were bitten by a tick and when it happened. Only people who get sick and/or get a rash after being bitten by a tick need antibiotics. If you are bitten by a tick and don’t get sick or get a rash, you don’t need antibiotics.


How is ehrlichiosis treated?

Ehrlichiosis is treated with an antibiotic.


Questions to Ask Your Doctor

  • I’ve been bitten by a tick. Should I call my doctor right away?
  • I’ve been bitten by a tick. Do I need any treatment?
  • If I need treatment, which antibiotic is best for me?
  • What tests can you do to ensure that I won’t get sick?
  • What tick or insect repellent should I use for my child?
  • Which tick or insect repellent is best for me?
  • I have HIV. Should I avoid areas where ticks may live?