Ehrlichiosis is a bacterial illness transmitted through tick bites, primarily caused by the bite of the lone star tick. It is more common in the southeastern and south-central United States but can also occur in other areas where ticks are prevalent. Caused by bacteria from the Ehrlichia species, the infection affects white blood cells and can lead to severe illness if not treated promptly.
Understanding the symptoms, causes, and available treatments is key to managing this condition and reducing health risks.
How Ehrlichiosis Spreads
Ehrlichiosis is spread to humans when they are bitten by an infected tick. The primary tick responsible is the lone star tick (Amblyomma americanum), though other species like the black-legged tick and the western black-legged tick can also be carriers.
Ticks often become infected after feeding on animals that harbor the Ehrlichia bacteria, such as deer or rodents. Humans are accidental hosts and cannot transmit the infection to others.
Signs and Symptoms of Ehrlichiosis
Symptoms typically appear within 5 to 14 days after a tick bite. In some cases, people do not remember being bitten. The illness can vary from mild to severe and usually begins with flu-like symptoms.
Common symptoms include:
- Fever and chills
- Severe headache
- Muscle aches
- Fatigue
- Nausea, vomiting, or diarrhea
- Confusion or mental fog
- Cough
- Joint pain
- Red eyes
- Rash (less common, especially in adults)
Symptoms may progress quickly, especially in older adults or individuals with weakened immune systems. Children may also show different symptom patterns.
Who Is at Risk for Ehrlichiosis
Anyone who spends time in tick-prone areas is at risk. This includes campers, hikers, hunters, and outdoor workers. Ticks are most active in warmer months, especially between April and October.
Certain factors increase risk:
- Living in or traveling to high-incidence areas
- Having frequent exposure to wooded or grassy environments
- Not using insect repellent or wearing protective clothing
- Failing to check for ticks after outdoor activities
Early detection and treatment are essential for avoiding complications.
How Ehrlichiosis Is Diagnosed
Diagnosis often begins with an evaluation of symptoms and recent tick exposure. Because early symptoms resemble other infections, Ehrlichiosis can be difficult to identify without laboratory testing.
Tests used include:
- Blood smear microscopy to detect infected white blood cells
- PCR (polymerase chain reaction) tests to detect Ehrlichia DNA
- Antibody tests (serologic tests) to confirm exposure, though these are more useful later in the illness
- Blood panel assessments that may show low white blood cell counts, low platelet levels, or elevated liver enzymes
Doctors may begin treatment before test results are confirmed if symptoms strongly suggest Ehrlichiosis.
Treatment Options for Ehrlichiosis
The first-line treatment is the antibiotic doxycycline, which is most effective when started early. Adults and children of all ages can take doxycycline for this condition. Most people respond to treatment within 24 to 48 hours.
Treatment typically lasts 7 to 14 days. Delayed treatment can result in more serious complications, including:
- Respiratory failure
- Nervous system disorders
- Kidney failure
- Seizures
- Coma
- Death in rare cases
Prompt antibiotic therapy significantly reduces the risk of severe outcomes.
Prevention Tips to Avoid Ehrlichiosis
Taking preventive steps is the best way to avoid Ehrlichiosis and other tick-borne illnesses. These measures help reduce contact with ticks:
- Wear long sleeves, long pants, and closed-toe shoes when in wooded or grassy areas
- Use EPA-approved insect repellents containing DEET, picaridin, or oil of lemon eucalyptus
- Treat clothing and gear with permethrin
- Stay on trails and avoid tall grass or brush
- Perform thorough tick checks after outdoor activities, especially in hidden areas like behind ears, underarms, and along the waistline
- Shower soon after coming indoors to help wash away unattached ticks
- Remove attached ticks promptly with fine-tipped tweezers
Pet owners should use veterinarian-recommended tick prevention methods to reduce risk of ticks in the home environment.
Tick Removal and Monitoring
If a tick is found attached, it should be removed carefully:
- Use tweezers to grasp the tick close to the skin’s surface
- Pull upward steadily without twisting
- Clean the area with rubbing alcohol or soap and water
- Monitor for symptoms for at least two weeks
Keeping the tick in a sealed container for identification can be helpful if symptoms develop.