Ehrlichiosis is a disease that primarily spreads through the bite of an infected tick.

Previously known as human monocytic ehrlichiosis, it can cause a wide range of symptoms, including aches, fever, chills, and gastrointestinal problems.

According to the Centers for Disease Control and Prevention (CDC), ehrlichiosis appears to be most prevalent in the Southeastern and South Central United States.

Prompt treatment reduces the risk of complications and severe illness. However, the best way to prevent ehrlichiosis is to avoid ticks and tick bites.

This article will discuss what ehrlichiosis is, including its symptoms, treatment options, and methods of prevention.

a lone star tick on persons skin where if it bites is could cause EhrlichiosisShare on Pinterest
Bites from infected lone star ticks are a common cause of ehrlichiosis.

According to the CDC, ehrlichiosis describes diseases that occur due to three types of bacteria. These bacteria are:

  • Ehrlichia chaffeensis
  • E. ewingii
  • E. muris eauclairensis

Most cases appear to be due to E. chaffeensis.

Ehrlichiosis seems to be most prevalent in the Southeastern and South Central U.S., particularly Arkansas, Missouri, New York, and Virginia. Most ehrlichiosis cases occur in the summer months.

In 2018, the CDC recorded 1,799 cases of E. chaffeensis infection. However, due to low reporting numbers, there are no data available on other types of ehrlichiosis infection.

The severity of the disease varies from one person to another. However, the CDC cite that the fatality rate is approximately 1% of all cases. Prompt treatment reduces the risk of severe disease.

Ehrlichiosis spreads through infected tick bites.

The lone star tick, or Amblyomma americanum, is the primary vector of E. chaffeensis and E. ewingii. The deer tick, otherwise known as Ixodes scapularis, is the main vector of E. muris eauclairensis.

Infected ticks spread ehrlichiosis when they latch onto a person’s skin and feed on their blood. The bacteria enter the person’s bloodstream through the bite.

Ticks can pick up the bacteria when they feed on an infected animal, such as a coyote.

Rarely, individuals may develop ehrlichiosis in other ways, such as:

  • through blood transfusions
  • through organ transplants
  • through mother-to-fetus transmission
  • through direct contact with a dead infected animal

Ehrlichiosis symptoms can resemble flu symptoms, and they usually appear 1–2 weeks after a person receives a bite from an infected tick.

Early signs and symptoms may include:

  • appetite loss
  • body aches and pains
  • chills
  • cough
  • diarrhea
  • fever
  • headache
  • malaise, or a general feeling of illness
  • nausea
  • rash, though this is more common in children
  • vomiting

The CDC state that the early stage symptoms, occurring within the first 5 days, are usually mild. If a rash is going to appear, it typically does so within this time.

The disease can progress in those who do not receive prompt medical treatment and in those who have a weakened immune system.

Later stages of the illness can cause more severe symptoms, such as:

  • meningoencephalitis, which is damage to the brain or nervous system resulting from inflammation
  • meningitis, which is inflammation of the membranes covering the brain and spinal cord
  • acute respiratory distress syndrome
  • symptoms of sepsis or shock
  • heart problems
  • coagulopathy, or uncontrolled bleeding

Late stage symptoms, such as meningitis and meningoencephalitis, can occur in up to 20% of people who get ehrlichiosis.

The antibiotic doxycycline (Doryx, Vibramycin) is the primary treatment for ehrlichiosis in adults and children.

Early treatment can reduce the risk of disease severity and death. According to one 2020 article, a person may need to take doxycycline for 5–7 days, depending on the severity of the condition.

People typically begin to improve within 48–72 hours of treatment.

People typically recover from ehrlichiosis. However, complications can occur in some cases, especially if a person does not receive prompt treatment.

Those who have a higher chance of experiencing severe illness include people who are very young or very old and people with a weakened immune system, such as those with HIV.

Potential complications include:

  • coma
  • excessive bleeding
  • heart failure
  • kidney failure
  • respiratory failure
  • seizures
  • septic shock

In a small number of people, complications can cause death.

The primary risk factor for ehrlichiosis is receiving a bite from an infected tick.

Factors that increase the risk of a tick bite include living in an area with a high tick population and spending time outdoors in the summer months, which is when tick populations peak.

According to the National Organization of Rare Diseases, a person may have a higher chance of receiving a tick bite during May, June, and July.

Older adults may also be at higher risk of ehrlichiosis. The CDC state that those aged 60–69 years “account for the highest number of cases.”

To prevent ehrlichiosis, people should try to avoid tick bites. To do this:

  • Wear long-sleeved shirts and long pants when outdoors. Tuck the shirt into the pants.
  • Do not wear open toed shoes. Wear socks and shoes, and tuck the pants into the socks.
  • Wear light colors to highlight ticks on the clothing before they attach to the skin.
  • Use a tick repellent containing DEET on the skin and clothing or one containing permethrin on the clothing only. Exercise caution when applying DEET to children, and always follow the instructions carefully.
  • Avoid grassy areas where possible, especially during peak tick seasons.
  • Check all backpacks and other outdoor equipment for the presence of ticks. Washing these items and placing them in the dryer on a high heat for 10 minutes can help kill ticks. Alternatively, treat fabrics with 0.5% permethrin.
  • Use appropriate tick treatments on pets regularly. Also, give them a daily tick inspection.

It is not possible for people to completely avoid exposure to ticks. Occasionally, a tick may attach itself to a person’s skin despite their best efforts to avoid them.

Finding and removing ticks

To find and remove ticks from the skin and clothing:

  • Visually inspect the clothes, skin, and hair for ticks after spending time outdoors. Ticks can be tiny, so it is important to be thorough.
  • Pay special attention to the legs, groin, belly button, underarms, back of the neck, and other areas of hidden skin.
  • Take a shower within 2 hours of coming indoors. Although taking a shower alone is unlikely to be enough to remove ticks, it can help when combined with a visual inspection.
  • Wear gloves and use flat-tipped tweezers to remove any ticks that are on the skin. Grab the tick by the area that is attached to the skin and slowly pull the tick up and out of the skin.
  • Place the tick in a container of rubbing alcohol to kill it. Never crush the tick, as this may release harmful bacteria. Alternatively, place it in a plastic bag in the freezer to save the tick for testing (should illness develop).

Following tick removal

Following the removal of any ticks, a person should:

  • Wash the bite site thoroughly with soap and water.
  • Clean the tweezers and any other equipment that the tick has been in contact with.
  • Dispose of the gloves and wash the hands.
  • Monitor the bite site for a rash and look for other symptoms of infection.

A person should see a doctor promptly if any symptoms develop. If possible, bring the frozen tick for testing.

Diagnosis of ehrlichiosis and other tick-borne diseases can be challenging because the symptoms resemble those of many other conditions.

To make a diagnosis, a doctor may ask about a person’s travel to any high risk regions and their general outdoor activities. They may also take blood tests to check for signs of infection, such as a low white blood cell count and abnormal liver function.

The results of the blood tests can take several weeks.

If a doctor suspects ehrlichiosis, they may prescribe antibiotics before the results come back. They may do this because prompt treatment improves outcomes.

The outlook for ehrlichiosis is typically good, providing a person receives prompt treatment. Most people respond well to antibiotic treatment and begin to feel better within 48–72 hours of treatment.

Untreated ehrlichiosis, however, can lead to complications. Some of these can be severe.

In 1% of cases, the disease can be fatal. However, some sources suggest that this may be an overestimation, as not everyone who gets ehrlichiosis will present for treatment.

A person should see a doctor if they develop any of the symptoms of ehrlichiosis, especially after receiving a tick bite or being in an area with a high tick population.

Ehrlichiosis is a tick-borne disease that causes flu-like symptoms.

Prompt treatment with antibiotics can quickly relieve the symptoms and prevent progression to a more severe illness.

If a person does not receive prompt treatment, ehrlichiosis can cause severe complications. In some cases, it can even be fatal.

The best way to prevent ehrlichiosis is to avoid exposure to ticks and tick bites.

If a tick does attach to the skin, remove it immediately. If any symptoms develop, see a doctor without delay.