February 8, 2017

Ehrlichiosis is a disease caused by the bacteria Ehrlichia chaffeensis which infects white blood cells (monocytes). Ehrlichia was previously known as human monocytic ehrlichiosis (HME). Signs and symptoms of ehrlichiosis include: fever, headache, nausea, and body aches. Encephalitis/ meningitis may occur. Ehrlichiosis is transmitted to a person through the bite of an infected lone star tick (Amblyomma americanum).

Ehrlichiosis occurs in parts of the United States, Europe and Africa. Around 600 cases of ehrlichiosis are reported in the United States annually. However, it is likely that the actual incidence is much higher as many cases are unreported, and many more may be symptom-free and therefore undiagnosed.

Ehrlichia are small, gram-negative bacteria, round or ellipsoidal in shape. They preferentially invade mononuclear phagocytes, such as monocytes and macrophages, and in some cases neutrophils. In all of these cell types they occupy cytoplasmic vacuoles, usually in bacterial microcolonies known as morulae. Ehrlichia cycle in nature between ticks and mammals, and can cause disease in many mammalian species.

Patients are most likely to be infected with Ehrlichia in spring and summer months, though cases occur into autumn as well. Unlike Lyme disease and Rocky Mountain spotted fever, ehrlichiosis strikes older people preferentially, probably due to immunological host factors. However, severe and even fatal cases have also been reported in children and young adults.


The bacteria are transmitted to humans by the bite of an infected tick. The lone star tick, the American dog tick (or wood tick) and the deer tick (or black-legged tick) have been associated with ehrlichiosis. Rickettsial bacteria cause a number of serious diseases worldwide, including Rocky Mountain spotted fever and typhus. All of these diseases are spread to humans by a tick, flea, or mite bite.

Scientists first described ehrlichiosis in 1990. There are two types of the disease in the United States –

  • Human monocytic ehrlichiosis (HME) is caused by the rickettsial bacteria Ehrlichia chaffeensis.
  • Human granulocytic ehrlichiosis (HGE) is also called human granulocytic anaplasmosis (HGA). It is caused by the rickettsial bacteria called Anaplasma phagocytophilum .

Ehrlichia bacteria can be carried by the –

  • American dog tick
  • Deer tick ( Ixodes scapularis ) — which can also cause Lyme disease
  • Lone Star tick

Risk Factors

  • Being outdoors in warm weather – Most cases of ehrlichiosis occur in the spring and summer months when populations of the Lone Star tick are at their peak, and people are outside more often.
  • Living in or visiting an area with a high tick population – People are at greater risk if they are in an area with a high Lone Star tick population. In the United States, Lone Star ticks are most common in southeastern, eastern and south-central states.
  • Being male – Ehrlichiosis infections are more common in males, possibly because of increased time outdoors for work and recreation.


The incubation period between the tick bite and when symptoms occur is about 7 – 14 days. Symptoms may seem like the flu (influenza), and may include –

  • Chills
  • Fever
  • Headache
  • Muscle aches
  • Nausea
  • Other possible symptoms:
  • Diarrhea
  • Fine pinhead-sized areas of bleeding in the skin (petechial rash)
  • Flat red rash (maculopapular rash) (uncommon)
  • General ill feeling (malaise)

A rash appears in fewer than one-third of cases. Sometimes, the disease may be mistaken for Rocky Mountain spotted fever. The symptoms are often general, but patients are sometimes sick enough to see a doctor.


People with weakened immune systems are at an even higher risk of more-serious and potentially life-threatening consequences. Serious complications of untreated infection include –

  • Kidney failure
  • Respiratory failure
  • Heart failure
  • Seizures
  • Coma


Antibiotics (tetracycline or doxycycline) are used to treat the disease. Children should not take tetracycline by mouth until after all their permanent teeth have grown in, because it can permanently change the color of growing teeth. Doxycycline that is used for 2 weeks or less usually does not discolor a child’s permanent teeth. Rifampin has also been used in patients who cannot tolerate doxycycline.

Alternative Treatment

Probiotic supplement containing Lactobacillus acidophilus – Probiotics, or “friendly” bacteria, help maintain intestinal health. If the patient takes antibiotics to treat Lyme disease, the antibiotics will kill the “good” bacteria along with the bad. That can cause diarrhea or yeast infections. Taking probiotics may reduce these side effects. People with weakened immune systems, or those who take drugs to suppress their immune systems, should ask their doctors before taking probiotics.

Beta-glucan – This is a kind of fiber, is sometimes used to help fight Lyme disease. Beta-glucan is thought to stimulate the immune system, so people with weakened immune systems, or those who take drugs to suppress their immune systems, should ask their doctors before taking it.

Garlic (Allium sativum) – This has antibacterial effects, and one study suggested it may help prevent tick bites. In that study, people who took garlic reported fewer bites than those who took a placebo. Garlic may increase the risk of bleeding, especially if the person also takes blood thinners such as warfarin (Coumadin), clopidogrel (Plavix), or aspirin. Garlic can potentially interfere with several medications, including drugs used to treat HIV/AIDS, and even some birth control medications. Speak to your doctor.

Essaic – Burdock root (Arctium lappa), sheep sorrel (Rumex acetosella), slippery elm (Ulmus fulva), rhubarb (Rheum palmate). It helps to treat Lyme disease. Essaic is a formula that contains several different herbs, and may interact with many medications and potentially cause some dangerous side effects.


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