Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at June 26, 2016

Babesiosis is a tick-borne disease caused by the Babesia microti parasite, which infects mainly red blood cells. This parasite is carried by ticks of the Ixodes scapularis, or blacklegged, deer tick-type. They are more common in the Northeastern area, particularly in New York state, New Jersey, and New England. They are also common in the Midwestern areas, particularly in Wisconsin and Minnesota. The ticks are also more common during the hotter months. 


Definition & Facts

Babesiosis take its name from the parasite that causes the condition in humans. The Babesia parasite is similar to the protozoans that cause malaria. It can infect humans through bites of the scapularis ticks when the ticks are infected by the parasite. According to the Centers for Disease Control and Prevention, people who get bitten by the Ixodes scapularis tick never recall feeling or seeing anything due to the minute, poppy seed-size of the tick.

Large farm and cattle areas and hot temperatures are usually the environments and conditions in which scapularis ticks to multiply. Farmers and people who do outdoor activities must watch out for deer, white-footed mice, hares, and other small mammals that are more likely to carry those ticks. Transmission can also happen from a blood transfusion from an infected, asymptomatic individual.

If two separate types of infected ticks bite someone, there is the possibility that babesiosis and Lyme disease could infect the person at the same time. However, babesiosis is typically very simple to treat as well as preventable.

Symptoms & Complaints

Babesiosis has a clinical profile that includes a wide variety of symptoms based on severity and on the individual’s immune system. Many infected with babesiosis will not have any symptoms or their symptoms may mimic those of the common cold

In otherwise healthy patients, babesiosis presents itself with symptoms that mimic the flu and that could last weeks or months. These include fevers, nausea and vomiting, depression, chills, and strong body aches.

Patients with compromised immune systems could experience severe symptoms that could be life-threatening. The most dangerous symptom is respiratory failure or renal failure, which are complications that can occur among patients with weakened immune systems.


The ticks that are infected with the Babesia parasite are the ones that are dangerous to humans. The main cause of babesiosis is exposure to the Ixodes scapularis tick. This is a deer tick that is black-legged, and it is the size of a poppy seed. This tick affects many farm animals and cattle in general, but it can also jump on white-legged mice, rabbits, hare, squirrels, and other small mammals. Therefore, it is suggested that people who work outdoors, work on farms, or are veterinarians of cattle and other farm animals get medical tests that will rule out any contagion.

The way that the exposure occurs is when the tick bites someone and the parasite enters the bloodstream. Another much rarer route of infection is through blood transfusions from someone who is infected. A third and even rarer route of infection occurs congenitally, from mother to child. Advances in the medical field can prevent this type of transmission from occurring with blood tests and antibiotics.

Diagnosis & Tests

The first step a clinician will take upon hearing the patient's concerns is to ascertain the geographical area where the patient has been potentially infected. According to the CDC it is customary to do checks on all cattle and farm animals in areas where the infection is detected.

If the exposure to the tick is in the areas where Lyme disease and babesiosis are suspected, blood tests are ordered to either rule out or prove the presence of parasites. Anemia is usually the first sign of the illness that alerts doctors; anemia is the result of the parasite attacking the red blood cells. Doctors will also look for high levels of serum lactate dehydrogenase, bilirubin, and sedimentation of blood cells.

There are two tests using stains that look for the presence of the Babesia parasite. They are the Wright's stain and Giemsa stain. There is also a test that looks for DNA traces of the parasite as well as for antibodies the body has produced to fight Babesia. 

Treatment & Therapy

As with many parasitic infections, antibiotic therapy that combines more than one medicine is a common course of action. For a period of 7 to 10 days, doctors may prescribe atovaquone, also known as Mepron®, which is a strong antiparasitic drug. Quinine, which is historically known as a medicinal agent, along with clindamycin, are also added to the regimen.

Patients must take the medications daily and exactly as prescribed. A side effect common to many of these medications is that they can upset the stomach. Therefore, it is recommended that they are taken before bed, after breakfast, or in the middle of the day when the stomach has been coated enough by food.

If the condition worsens, it is recommended that the medicine is injected intravenously for longer periods of time and in higher doses. The doctors will continue to get blood samples to see the progress of the parasite in the bloodstream. 

Prevention & Prophylaxis

Prevention involves sticking to paths or cleared walkways when traveling in wooded areas or areas with dense grass. It is also wise to cover up and minimize the amount of skin exposed when in such areas. In addition, it is important to always wear insect repellents such as tick repellents when active outdoors in heavily wooded areas or areas known to have ticks.

Avoiding outdoor activities or exposure to specific types of animals during the months when ticks are most active could also be prudent. It is important to check one's body after outdoor activity. Pets should also be checked, and the exams should be thorough. If ticks are found, they should be removed immediately.

Prevention also involves farmers conducting routine checks in farm areas. During the months of the year that temperatures get warmer, farmers are encouraged to check their animals for signs of distemper, rabies, and other signs of diseases caused by pathogens.