Anaplasmosis is a tick-borne illness. This means that it’s spread by tick bites. It has numerous symptoms.

A black-legged tick infected with a bacterium called Anaplasma phagocytophilum can spread anaplasmosis to a person or animal. This causes symptoms like fever, chills, and aches.

Anaplasmosis can also be spread by a blood transfusion, but it’s less common.

Keep reading to learn more about anaplasmosis signs and complications, as well as when to get medical treatment.

Blacklegged ticks are common in the eastern United States. They usually bite in the spring, summer, and fall, although it’s possible to be bitten in the winter if the temperature is above freezing.

If you’ve been bitten by an infected tick, it takes around 1 to 3 weeks for symptoms to appear.

But tick bites aren’t always noticeable. Some people get bitten without even realizing it. In addition, not everyone experiences symptoms.

Early illness

In the early stages, anaplasmosis causes mild to moderate flu-like symptoms, including:

Late illness

If left untreated, anaplasmosis can cause life threatening symptoms, including:

  • anemia and other blood problems
  • confusion and disorientation
  • difficulty breathing
  • dizziness
  • organ failure

Most cases of anaplasmosis improve with treatment. Sometimes, anaplasmosis causes serious complications, and in very rare cases, anaplasmosis can lead to death.

According to a 2022 systematic review of 88 articles and 110 people with anaplasmosis, death occurred in approximately 5.7% of cases.

But the study’s authors specified that people with weakened immune systems were at a much greater risk of death (18.2%) compared to those with healthy immune systems (4.2%).

You might have a weakened immune system if you have a chronic illness, like kidney disease, diabetes, or untreated HIV. You might also have a weakened immune system if you’ve had an organ transplant.

Certain medical treatments, including chemotherapy, can also compromise your immune system.

According to the Centers for Disease Control and Prevention (CDC), delayed treatment and older age are also risk factors for severe anaplasmosis.

Anaplasmosis can affect your pets. If an infected tick has bitten your dog or cat, they might experience flu-like symptoms, including:

  • difficulty walking
  • fever
  • joint pain
  • lack of appetite
  • tiredness

In dogs and cats, less common symptoms include vomiting, diarrhea, and shortness of breath. Infections may last up to 1 week.

Anaplasmosis can affect livestock, including:

  • cattle
  • sheep
  • goats
  • bison
  • cervids (deer, elk, and moose)

Some signs and symptoms of anaplasmosis in livestock include:

  • loss of a fetus
  • anemia
  • blood in urine
  • constipation
  • depression
  • fever
  • jaundice
  • lack of appetite
  • respiratory problems
  • sudden decrease in milk production
  • weakness
  • sudden death

Anaplasmosis symptoms can resemble those of other viral illnesses. If you don’t remember being bitten by a tick, you might not know if you’re at risk.

But in many parts of the United States, tick-borne illnesses are on the rise. If you’re experiencing symptoms and have spent time outdoors or with family pets, speak with a healthcare professional.

Although there’s no rapid test to diagnose anaplasmosis, a blood test can help.

It can take up to several weeks for your blood test results to come back. In the meantime, your doctor might prescribe an antibiotic to lower your risk of complications.

Medical emergency

Some symptoms of anaplasmosis are signs of a life-threatening emergency. You should call emergency medical services right away if you experience:

  • confusion or disorientation
  • difficulty breathing or shortness of breath
  • severe abdominal pain
  • severe vomiting or vomiting that doesn’t stop
  • sudden dizziness or loss of consciousness

Most of the time, symptoms of anaplasmosis resolve within a few weeks.

According to the 2022 systematic review mentioned above, the duration of symptoms was reported in 53 cases.

On average, symptoms of anaplasmosis lasted for approximately 21 days in people who were hospitalized, many of whom were immunocompromised.

Symptoms of anaplasmosis usually diminish quickly after about 48 hours of starting treatment, according to a 2022 study of 25 anaplasmosis cases contracted in Quebec, Canada.

According to that same study, researchers found that nearly half of all people required hospitalization, but only one required intensive care.

Like Lyme disease, anaplasmosis is spread by tick bites. If an infected tick bites you, you could experience symptoms within a couple of weeks. But it’s not always possible to know you’ve been bitten by a tick.

The symptoms of anaplasmosis resemble the flu and include fever, muscle aches and pains, and gastrointestinal symptoms. If you suspect you have anaplasmosis, talk with a healthcare professional to find out more.