Diseases & Conditions

Ehrlichiosis

Ehrlichiosis is a bacterial illness transmitted by ticks. Ehrlichiosis causes flu-like symptoms. Another tick-borne infection — anaplasmosis — is closely related to ehrlichiosis. But the two have distinct differences and are caused by different microorganisms.

The signs and symptoms of ehrlichiosis range from mild body aches to severe fever and usually appear within a week or two of a tick bite. If treated quickly with antibiotics, ehrlichiosis generally improves within a few days.

Ehrlichiosis is most common in spring and summer, when ticks are active and you're more likely to be outdoors.

The best way to prevent these infections is to avoid tick bites. Tick repellents, thorough body checks after being outside and proper removal of ticks give you the best chance of avoiding ehrlichiosis.

If a tick infected with ehrlichia or anaplasma bites you, the following flu-like signs and symptoms may appear within five to 14 days of the bite:

• Mild fever
• Headache
• Muscle aches
• Nausea
• Vomiting
• Diarrhea
• Cough
• Joint pain
• Confusion
• Rash — rare in adults, but more frequent in children

Some people infected with ehrlichiosis may have symptoms so mild that they never seek medical attention, and the body fights off the illness on its own. But untreated ehrlichiosis with persistent symptoms can result in an illness serious enough for hospitalization. If you experience any of the above symptoms soon after you've been in an area that you know has ticks, see your doctor.

Ehrlichiosis is caused by Ehrlichia chaffeensis bacteria and is transmitted primarily by the Lone Star tick.

Ticks feed on blood, latching onto a host and feeding until they're swollen to many times their normal size. During feeding, ticks that carry disease-producing bacteria can transmit the bacteria to a healthy host. Or they may pick up bacteria themselves if the host is infected.

To get ehrlichiosis, you must be bitten by an infected tick. The bacteria enter your skin through the bite and eventually make their way into your bloodstream. Before bacteria can be transmitted, a tick must be attached and feeding for at least 24 hours. An attached tick that has a swollen appearance may indicate that enough time has elapsed to transmit bacteria. Removing the tick as soon as possible may prevent infection.

It may take 14 days after a tick bite for you to begin showing signs and symptoms of ehrlichiosis. If you get symptoms within two weeks of a tick bite, see your doctor. Be sure to tell your doctor that you recently received a tick bite or visited an area with a high population of ticks.

Tick-borne infections are difficult to diagnose based solely on symptoms because the symptoms are similar to many other common causes of fever or body aches.

A pattern of abnormal blood tests may lead your doctor to a diagnosis. Your doctor may prescribe antibiotics after analyzing your symptoms and may have you undergo a specific diagnostic blood test. If the symptoms don't subside with your doctor's recommendations, see your doctor for a follow-up visit.

If it's suspected that you have ehrlichiosis, your doctor will likely give you a prescription for an antibiotic such as tetracycline or doxycycline. You'll generally take the antibiotics for seven to 10 days and should see the signs and symptoms subside. Your doctor may have you take antibiotics for a longer period if you're at risk of contracting Lyme disease as well.