What is Babesiosis?
Babesiosis is a disease caused by a parasite known as Babesia that’s commonly spread through tick bites and primarily targets animals. Humans can also get infected but they are not the usual hosts. This parasite is sometimes called piroplasms due to its pear shape seen within infected red blood cells.
While babesiosis is fairly uncommon in the USA, it is typically found in specific regions. A lot of people carrying this parasite might not show any signs of the disease, but it can cause serious health problems and, in some cases, death especially in people with weak immune systems, without spleens, or the elderly.
Diagnosing babesiosis can be challenging and requires a high level of awareness, particularly in areas where it’s commonly found. Treating the disease is strongly recommended even when patients show no symptoms, as this can prevent the health condition from getting worse and spreading to others.
What Causes Babesiosis?
Babesiosis is an infection caused by a parasite known as Babesia. Babesia comes in four different types or “clades”. The most common one is Babesia microti, typically spread by ticks that carry this parasite.
People can contract babesiosis when bitten by an infected tick. But it can also be transmitted through a blood transfusion, meaning you can get it even if you’ve never visited areas where ticks are common. There are even cases where babesiosis has been passed from a mother to her baby during pregnancy.
Once inside the body, Babesia parasites infect red blood cells, where they may appear as oval or pear shapes. Their location and shape inside red blood cells often lead to confusion with another parasite, plasmodium falciparum.
Unlike plasmodium, Babesia does not typically cause the destruction of red blood cells, but it does lead to them clumping together and becoming stiffer. This can cause problems like acute respiratory distress and fluid build-up in the lungs. It can also cause blockages in blood vessels in other organs due to fragmented red blood cells. The spleen which acts to filter and remove damaged blood cells, can become enlarged as a result. People without a spleen often experience a more severe course of the disease.
Interestingly, the Ixodes tick that spreads Babesia is the same one that also spreads a type of bacteria called B.Burgdorferi.
Risk Factors and Frequency for Babesiosis
Out of the numerous Babesia species capable of infecting vertebrates, only a few have been shown to infect humans. They are typically transmitted by Ixodes ticks, which use small vertebrates like rodents and birds as a primary food source. This relationship allows the ticks to complete their life cycle. Meanwhile, larger mammals, such as deer, supply the ticks with blood meals which help sustain their adult populations. However, they don’t act as hosts for the organism.
Humans who get infected by these ticks tend to be accidental hosts. In the United States, most cases of Babesiosis occur in the Northeast and upper Midwest regions, and are usually a result of the tick species Ixodes scapularis transmitting the Babesia microti parasite. There are frequent infections during late spring to fall, owing to increased interaction between humans, ticks and their hosts. As of recent, this infection rate has been noticed to increase.
- In the Pacific Northwest, Babesiosis occurs infrequently and is caused by the Babesia duncani species, transmitted by the Ixodes pacificus tick.
- In Europe, Babesiosis tends to be caused by Babesia divergens.
Signs and Symptoms of Babesiosis
Babesiosis is an illness that can cause a variety of health issues, from no symptoms at all to severe infection that impacts multiple organs in the body. How seriously babesiosis affects someone often depends on the health of their immune system. Some people, especially adults and children with a healthy immune system may not show any signs of infection. For those who do experience symptoms, these usually appear between one to six weeks after infection.
People with a strong immune system often encounter symptoms similar to having a flu, which may include fever, chills, tiredness, and headaches. Less common symptoms can include cough, joint pain, sore throat, stomach ache, nausea, changes in mood, and depression. During a physical exam, the doctor might find an enlarged liver or spleen, yellowing of the skin or eyes (jaundice), changes in the eyes, or a red throat. It’s worth mentioning that a skin rash is not common in babesiosis, and if present, it could suggest a co-infection with Lyme disease.
- Fever
- Chills
- Tiredness
- Headaches
- Cough (less common)
- Joint pain (less common)
- Sore throat (less common)
- Stomach ache (less common)
- Nausea (less common)
- Mood changes (less common)
- Depression (less common)
Severe babesiosis usually affects people at higher risk for health problems, especially in individuals without a spleen. These high-risk patients may have multiple organs affected, including the lungs, heart, kidneys, and liver, and complications could occur such as blood clotting disorder (disseminated intravascular coagulation, or DIC) or coma.
Testing for Babesiosis
In diagnosing babesiosis, a disease caused by microscopic parasites that infect red blood cells, doctors often look for the parasites in a blood sample stained with special dyes. Sometimes, the parasite levels might be low early on in the infection, so several blood samples may need to be checked.
The parasites often appear in a ring shape within the blood cells and sometimes can even form a pattern resembling a Maltese cross. Laboratory tests using the PCR method, which can detect the DNA of the parasite, can be even more accurate than looking at blood samples under the microscope. These tests are usually done at specialized labs.
Doctors can also perform a test called serology, which checks for antibodies against the parasite in your blood. However, this test doesn’t tell whether the infection is recent or old. But, if the antibodies increase four times or more between the initial and later stages of infection, this suggests a recent infection.
People with babesiosis often show other changes in their blood tests, which may include anemia (low red blood cell count), an increase in enzymes called LDH, reduced platelets, liver enzyme elevations, proteins in urine, and increased levels of BUN and creatinine which are signs of kidney problems.
In looking at the blood sample, doctors can distinguish babesiosis from similar diseases caused by the Plasmodium parasite because babesiosis does not cause the formation of brown pigment precipitates in blood cells, the development of parasite stages (like gametocytes and schizonts seen in Plasmodium infections) does not occur at the same time, and the parasites vary in size and shape, mostly seen along the edges of the blood cells.
Treatment Options for Babesiosis
Treatment for specific diseases is typically necessary in cases where symptoms are present or in patients who have positive results from certain tests for over three months. There are two main treatment plans commonly used in mild to moderate disease situations. The first and most commonly used treatment involves combining atovaquone with azithromycin. The other option combines quinine with clindamycin, but this option carries a higher chance of adverse drug reactions compared to the atovaquone/azithromycin combination – 72% versus 15% respectively. A 7 to 10-day course of either treatment plan is suggested.
For severe cases of the disease that require hospital stay or cause organ failure, the preferred treatment is usually a combination of clindamycin and quinine. This is typically the case for high-risk individuals or those infected with the B. divergens species. It should be noted that this therapy can affect the heart’s rhythm, so careful monitoring is needed.
The length of treatment usually lasts from 7 to 10 days, but this can vary based on clinical observation and lab results. For patients with conditions that compromise the immune system, the disease might persist or reoccur. In such cases, treatment should continue for at least six weeks or for a minimum of two weeks after parasites are no longer detected through blood tests. If standard therapy doesn’t work, other combinations of drugs including atovaquone, azithromycin, clindamycin, and doxycycline, can be utilized. However, no single combination of this anti-parasite medication has proven to be superior. If at all possible, it’s also recommended to minimize existing immunosuppression.
When patients present with high levels of parasites in their blood and low hemoglobin levels, partial or complete red blood cell exchange transfusions may be necessary. This is particularly true if the patient faces lung, kidney, or liver dysfunction due to the infection, regardless of the level of parasites present in the blood.
In cases of severe disease, it’s common for patients to experience breathing difficulties. These patients must be closely monitored in an intensive care unit. This respiratory distress is usually caused by the release of toxins following the breakdown of red cells induced by medication.
What else can Babesiosis be?
When trying to identify the cause of certain symptoms, doctors may need to rule out a number of conditions. These could include:
- Colorado Tick Fever
- Rocky Mountain Spotted Fever
- Malaria
- Ehrlichiosis
- Q Fever
- Anemia
- Typhoid Fever
All these conditions may show similar symptoms, so it’s essential for the doctor to carry out the right tests to accurately pinpoint what’s causing the illness.
What to expect with Babesiosis
The outcome of babesiosis, a tick-borne disease, largely depends on the symptoms experienced by the patient. Most people with this disease do not show any symptoms and generally have a good prognosis. Some may experience symptoms akin to the flu, but they too are expected to have a good outcome. However, individuals suffering from a severe form of the disease can face continuous health issues related to multiple organ dysfunction, and in worst-case scenarios, the disease can even lead to death. Such fatal outcomes are generally seen in people who do not have a spleen.
The symptoms of babesiosis can last for quite a while, typically between 6 to 8 weeks. People without symptoms may unknowingly carry the disease for years. If smear tests for the disease are still positive three months after the initial treatment, patients must undergo a second round of treatment, regardless of whether they have experienced seizures or not.
It’s important to note that about one in five people with babesiosis may also be infected with Lyme disease, a co-infection that tends to prolong the duration of the symptoms.
Possible Complications When Diagnosed with Babesiosis
Complications from intravascular hemolysis, which is the destruction of red blood cells in the bloodstream, can lead to various health problems. These include:
- Jaundice – a condition that causes yellowing of the skin and eyes
- Shock – a life-threatening condition that requires immediate medical intervention
- Hemoglobinuria – the presence of hemoglobin in the urine
- Splenic rupture – a tear in the spleen
- Death
- ARDS (Acute respiratory distress syndrome) – a severe lung condition where oxygen levels in the blood become dangerously low
- Renal dysfunction – problems with kidney function
- Noncardiogenic heart failure – a type of heart failure not caused by a problem with the heart itself
