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Ehrlichiosis

What is ehrlichiosis?

Ehrlichiosis is a bacterial infection that infects animals, such as dogs, deer, coyotes, and mice. Sometimes the disease spreads to humans.

How does it occur?

People can become infected when they are bitten by a tick. If a tick bites an animal infected with ehrlichiosis and then bites you, you may become infected. The infection does not spread from person to person. In the US, the disease occurs mainly in the southeastern and south central regions of the country.

What are the symptoms?

The symptoms of ehrlichiosis vary. They may appear within several days to 3 weeks of a tick bite. In most cases the symptoms are mild flulike or coldlike symptoms, such as:

  • muscle aches
  • tiredness
  • headache
  • fever
  • chills.

Sometimes the symptoms include:

  • nausea
  • vomiting
  • cough
  • joint pain
  • confusion.

Unlike some other infections spread by ticks, the infection does not usually cause a rash.

How is it diagnosed?

Your healthcare provider will ask about your symptoms and your history of exposure to ticks. He or she will examine you. You may have some blood tests. If your blood tests show a low white blood cell count, low platelets, or abnormal liver tests, it is more likely that you have ehrlichiosis. There are 2 specialized tests available in some labs that can give additional evidence for ehrlichiosis infection. These blood tests look for the genes of the ehrlichiosis bacteria and for antibodies in your blood to the bacteria.


Because early treatment can prevent complications from the infection, treatment is often begun before you have the test results.

How is it treated?

Ehrlichiosis is treated with antibiotics, usually for 7 to 10 days. If your symptoms are severe, you may be treated in the hospital.

How long will the effects last?

Without treatment, the symptoms of ehrlichiosis may last for up to 2 months. Once you start taking antibiotics, you will usually start feeling better in a couple of days.


Rarely, especially without prompt treatment, the infection can become severe and life threatening, causing serious complications such as infection in the brain, seizures, or heart failure.

How can I take care of myself?

Take your medicines just as prescribed by your healthcare provider. Get plenty of rest.


Call your healthcare provider if:

  • Your symptoms are not getting better after at least 2 days of antibiotics.
  • Your symptoms are getting worse even though you have started taking antibiotics.
  • You have finished your antibiotics and keep having symptoms.
  • You start to have symptoms again after finishing your antibiotics.

How can I help prevent ehrlichiosis?

Because ehrlichiosis is spread by ticks, the best way to avoid getting it is to avoid getting bitten by ticks. If you are bitten, remove the tick as soon as possible.

  • Be aware of the areas where ticks live. Do not walk, camp, or hunt in the woods of tick-infested areas without precautions. In areas of thick underbrush, try to stay near the center of trails.
  • When you are outdoors, wear long-sleeved shirts tucked into your pants. Wear long pants tucked into your socks or boot tops if possible. A hat may help, too. Wearing light-colored clothing may make it easier to spot the small tick before it reaches your skin and bites.
  • Use approved tick repellents on exposed skin and clothing. Follow the directions on the package. Don't put repellent on open wounds or rashes. Wash the spray off your hands. Be careful when you use repellents on children because the repellents can make them sick.

    DEET is a very effective repellent, but adults should use preparations with no more than 35% DEET, and children should use repellents with no more than 10% DEET. DEET should be washed off your body when you go back indoors.


    Picaridin is another repellent recently made available in the US. It can be less irritating to the skin than DEET and appears to be just as effective.


    Some products containing permethrin are recommended for use on clothing, shoes, bed nets, and camping gear. Do not put permethrin on your skin.

  • Treat household pets for ticks and fleas. Check pets after they've been outdoors.
  • Brush off clothing and pets before entering the house.
  • After you have been outdoors, undress and check your body for ticks. They usually crawl around for several hours before biting. Check your clothes, too. Wash them right away to remove any ticks.
  • Shower and shampoo after your outing.
  • Inspect any gear you have carried outdoors.
  • Remove an attached tick with tweezers by gripping the tick as close to your skin as possible and gently pulling it straight away from you until it releases its hold. Don't twist the tick as you pull, and don't squeeze its body. Thoroughly wash your hands and the bite area and apply an antiseptic such as rubbing alcohol.
  • If you spend much time hiking, you may want to include a pair of tick tweezers in your first-aid kit. The tweezers are available at many sporting goods stores.

Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.


HIA File infd4546.htm Release 13/2010

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