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A Guide to Lesser Known Tick-Borne Illnesses

A Guide to Lesser Known Tick-Borne Illnesses

Getting bitten by a tick may be the start of complex medical conditions in patients. Ticks that transmit the bacteria that causes Lyme disease often carry other disease-causing microbes that can cause multiple tick-borne illnesses in humans.

Entomologist takes dangerous tick for researchThese tick-borne diseases complicate a person’s health, leading to more symptoms and longer recovery periods. As with Lyme disease, early detection of these other illnesses can lead to more effective treatment and reduce the chances of suffering more serious, long-term medical conditions.

Understanding co-infections

Tick-borne illnesses are animal diseases that can be transmitted to humans. Ticks get diseases from animals, like squirrels, mice, and deer; infections get passed to humans through the tick’s bite.Ticks that acquire more than one bacteria, virus, or protozoan at once can pass on multiple diseases or co-infections to humans with a single bite. Ixodes ticks that transmit Borrelia burgdorferi, the bacterium that causes Lyme disease, can also carry bacteria and viruses that may lead to co-infections, such as:
  • Anaplasmosis
  • Babesiosis
  • Ehrlichiosis
  • Rocky Mountain Spotted Fever
  • Tularemia

Numbers of patients with Lyme disease co-infections

Co-infections are common, especially in those diagnosed with chronic Lyme disease, as reported in a survey.The survey showed that more than half of the more than 3,000 patients diagnosed with chronic Lyme disease had co-infections. Of those with co-infections, about 30% had two or more co-infections. A Canadian study showed similar results.According to the survey, Babesiosis was the most common co-infection at 32%. The other rates of co-infection in surveyed patients were as follows:
  • Bartonellosis (28%)
  • Ehrlichiosis (15%)
  • Mycoplasma (15%)
  • Anaplasmosis (5%)
  • Rocky Mountain Spotted Fever (6%)
  • Tularemia (1%)
According to the CDC, ticks may carry some species of Bartonella bacteria, but there is “no causal evidence” that ticks can transmit the infection to humans through their bites.The survey also showed that patients with chronic Lyme disease had a much lower quality of life. Their bad physical and mental health days were more frequent, their diseases negatively impacted their ability to work, and they spent more money on related medical costs.

A deeper look at each co-infection


Babesia is a malaria-like parasite that causes the disease babesiosis, which is an infection of the red blood cells. Pregnant women who are bitten by infected ticks can pass this disease onto their children. Though it shares similar symptoms to Lyme disease, babesiosis more often starts with a high fever and chills. As the infection progresses, patients may develop
  • Headaches
  • Fatigue
  • Severe sweating
  • Muscle aches
  • Chest pain
  • Hip pain
  • Shortness of breath
While the symptoms can be so mild that they are overlooked, they can be life-threatening to those with compromised immune systems and the elderly. Delayed detection and treatment can lead to more severe medical complications, including:
  • Low blood pressure
  • Liver problems
  • Severe hemolytic anemia
  • Kidney failure
With babesiosis, early detection is critical. Blood tests can detect the disease, but they are most reliable within the first two weeks of infection. Often, babesiosis can be treated with a combination of antimalarial drugs and antibiotics. Some patients experience relapses, requiring additional retreatment.


Ehrlichiosis is a term used to describe several diseases caused by the bacteria Ehrlichia chaffeensis, E. ewingii, or E. muris eauclairensis. One in three patients infected develops a rash that can look like red splotches or pinpoints. The rash often comes about five days after having a fever. Others symptoms include headaches, muscle aches, and upset stomach. The disease is detected with blood tests and treated with antibiotics. Early detection can reduce the risk of more serious complications, including
  • Meningoencephalitis
  • Respiratory failure
  • Severe bleeding
  • Death
Those with weakened immune systems, the very young, and the elderly are at greater risk of severe illnesses. Like other tick-borne illnesses, ehrlichiosis can easily be missed by physicians.


Formerly known as Human Granulocytic Ehrlichiosis, anaplasmosis often is considered less severe than other tick-borne diseases. However, factors such as age, suppressed immunities, and delayed detection and treatment can lead to more serious conditions.Those with this disease may experience fever, severe headaches, chills, malaise, and gastrointestinal symptoms. Less than 10% of those with anaplasmosis get a rash. The disease is commonly treated with antibiotics.

Rocky Mountain spotted fever

Rocky Mountain spotted fever shares similar symptoms to other tick-borne illnesses, such as headache and fever. However, this disease progresses quickly, leading to a serious, life-threatening illness.A rash, which appears within four days of a tick bite, is the most common sign among patients. While not all patients will get a rash, Rocky Mountain spotted fever can be difficult to diagnose because the rash may not appear early in the illness.Once the disease is treated with antibiotics, patients do not suffer from chronic infections later. Those treated for severe Rocky Mountain spotted fever may still suffer from long-term conditions, including paralysis, hearing loss, and mental disabilities.


Caused by the bacterium, Francisella tularensis, tularemia causes headaches, sudden fever, dry cough, progressive weakness, and upset stomach. Tularemia can be fatal, so it needs to be treated as soon as possible with antibiotics.

Prevention of tick-borne diseases

As the number of cases of Lyme disease and co-infections continues to rise, patients should be informed of the best ways to prevent these illnesses. Some of the best ways to prevent these diseases are:
  • Use insect repellent
  • Remove ticks promptly
  • Reduce tick habitat in yards

Information about tick-borne illness testing

Since tick-borne illnesses share many of the same signs and symptoms, the right diagnostic tests can help doctors make the most accurate diagnoses. More information about laboratory testing is available here