Babesiosis
Babesiosis is an often-overlooked tick-borne infection. In some individuals, symptoms persist despite appropriate diagnosis and treatment of Lyme disease. Too often, people are told they have done “everything right” to treat Lyme disease, yet continue to struggle with fatigue, shortness of breath, palpitations, night sweats, or a lingering sense that something is still being missed. In others, babesiosis may be present even without Lyme disease. Individuals may undergo extensive evaluation for cardiac, pulmonary, or other medical conditions, with normal testing and imaging, but no clear explanation or path forward.
Early in my training in Lyme and tick-borne disease, I was mentored by Richard Horowitz, a pioneer in the field, for whose guidance I remain deeply grateful. One message he repeated often has stayed with me throughout my career: “Don’t forget about Babesia.” At the time, learning to recognize and treat Lyme disease alone felt overwhelming. But as I deepened my understanding of babesiosis, it became clear how many people were suffering from this parasitic infection without knowing it — sometimes even after Lyme disease had been diagnosed and treated.
That realization changed how I practice. By consistently considering babesiosis as part of a broader tick-borne disease evaluation, I have been able to help many individuals who were not improving find clarity and move toward recovery. This page is meant to bring awareness to babesiosis, explain why it is so often missed, and help ensure it is not overlooked in the evaluation of persistent or unexplained symptoms following tick exposure.
As a Lyme-literate physician with over 16 years of experience treating complex tick-borne illness, I provide comprehensive education, evaluation, and individualized care for people affected by Lyme disease and associated infections via telehealth.
Early in my training in Lyme and tick-borne disease, I was mentored by Richard Horowitz, a pioneer in the field, for whose guidance I remain deeply grateful. One message he repeated often has stayed with me throughout my career: “Don’t forget about Babesia.” At the time, learning to recognize and treat Lyme disease alone felt overwhelming. But as I deepened my understanding of babesiosis, it became clear how many people were suffering from this parasitic infection without knowing it — sometimes even after Lyme disease had been diagnosed and treated.
That realization changed how I practice. By consistently considering babesiosis as part of a broader tick-borne disease evaluation, I have been able to help many individuals who were not improving find clarity and move toward recovery. This page is meant to bring awareness to babesiosis, explain why it is so often missed, and help ensure it is not overlooked in the evaluation of persistent or unexplained symptoms following tick exposure.
As a Lyme-literate physician with over 16 years of experience treating complex tick-borne illness, I provide comprehensive education, evaluation, and individualized care for people affected by Lyme disease and associated infections via telehealth.
What Is Babesiosis?
Babesiosis is an emerging tick-borne disease caused by Babesia, an intraerythrocytic protozoan parasite that infects red blood cells. In the United States, the most common species known to cause human infection include Babesia microti, Babesia duncani, and Babesia odocoilei.
The organism was first identified in 1888 by Romanian bacteriologist Victor Babes, and more than 100 species of Babesia have since been described worldwide. Human infection in the United States was first recognized in the 1960s, with Babesia duncani identified in California in 1966 and Babesia microti identified in Massachusetts in 1967. In 2011, babesiosis was designated a nationally notifiable disease by the Centers for Disease Control and Prevention (CDC).
Babesia parasites invade red blood cells and replicate inside them, ultimately causing rupture of the cell. This process can lead to hemolytic anemia, reduced oxygen delivery to tissues, and a wide range of clinical symptoms. The severity of illness can vary significantly, ranging from asymptomatic infection to severe or life-threatening disease.
Babesiosis is one of several tick-borne infections that may affect individuals following tick exposure.
👉 Learn more about Lyme disease and other tick-borne diseases
The organism was first identified in 1888 by Romanian bacteriologist Victor Babes, and more than 100 species of Babesia have since been described worldwide. Human infection in the United States was first recognized in the 1960s, with Babesia duncani identified in California in 1966 and Babesia microti identified in Massachusetts in 1967. In 2011, babesiosis was designated a nationally notifiable disease by the Centers for Disease Control and Prevention (CDC).
Babesia parasites invade red blood cells and replicate inside them, ultimately causing rupture of the cell. This process can lead to hemolytic anemia, reduced oxygen delivery to tissues, and a wide range of clinical symptoms. The severity of illness can vary significantly, ranging from asymptomatic infection to severe or life-threatening disease.
Babesiosis is one of several tick-borne infections that may affect individuals following tick exposure.
👉 Learn more about Lyme disease and other tick-borne diseases
How Babesiosis Is Transmitted?
Babesiosis is most commonly transmitted to humans through the bite of an infected blacklegged tick (Ixodes scapularis in the eastern and midwestern United States and Ixodes pacificus in the western United States). Transmission from a tick bite can occur in less than 36 hours, which is shorter than is often assumed.
In addition to tick exposure, babesiosis may also be transmitted through blood transfusion, organ transplantation, and from mother to fetus during pregnancy.
Historically, babesiosis was considered geographically limited, but its range has expanded. The highest incidence of babesiosis continues to be reported in the Northeast and Midwest. Surveillance data show that approximately 98% of reported cases occur in residents of ten states: Connecticut, Maine, Massachusetts, Minnesota, New Hampshire, New Jersey, New York, Rhode Island, Vermont, and Wisconsin. In 2023, the CDC babesiosis surveillance summary formally recognized Vermont, New Hampshire, and Maine as states with endemic disease.
Because the same ticks that transmit Lyme disease can also transmit Babesia, co-infection is common, particularly in endemic regions.
In addition to tick exposure, babesiosis may also be transmitted through blood transfusion, organ transplantation, and from mother to fetus during pregnancy.
Historically, babesiosis was considered geographically limited, but its range has expanded. The highest incidence of babesiosis continues to be reported in the Northeast and Midwest. Surveillance data show that approximately 98% of reported cases occur in residents of ten states: Connecticut, Maine, Massachusetts, Minnesota, New Hampshire, New Jersey, New York, Rhode Island, Vermont, and Wisconsin. In 2023, the CDC babesiosis surveillance summary formally recognized Vermont, New Hampshire, and Maine as states with endemic disease.
Because the same ticks that transmit Lyme disease can also transmit Babesia, co-infection is common, particularly in endemic regions.
Signs and Symptoms of Babesiosis
The incubation period for babesiosis is typically one to six weeks following exposure, though symptoms may appear sooner or be delayed. Clinical presentation varies widely and may range from asymptomatic infection to severe or life-threatening illness.
Common signs and symptoms of babesiosis may include:
Since Babesia infects red blood cells, complications such as hemolytic anemia may occur. Symptoms may be prolonged, relapsing, or fluctuate over time, and chronic babesiosis has been documented.
Common signs and symptoms of babesiosis may include:
- Fever and chills
- Fatigue
- Headache or head pressure
- Joint and muscle pain
- Excessive sweating or night sweats
- Heart palpitations
- Chest pain
- Shortness of breath or a sensation often described as “air hunger”
- Unexplained cough
- Enlargement of the spleen (splenomegaly)
Since Babesia infects red blood cells, complications such as hemolytic anemia may occur. Symptoms may be prolonged, relapsing, or fluctuate over time, and chronic babesiosis has been documented.
Why Babesiosis Is Often Missed
Babesiosis is frequently under-recognized and misdiagnosed, particularly in areas where Lyme disease is more widely known. Several factors contribute to this, even among individuals who have already been diagnosed with a tick-borne illness.
Symptoms of babesiosis can be nonspecific and overlap with those of Lyme disease, viral infections, anemia, or other inflammatory conditions. Fatigue, headaches, muscle pain, shortness of breath, and night sweats may be attributed to stress, post-viral syndromes, menopause, or residual Lyme symptoms rather than a parasitic infection.
Babesiosis may also be overlooked because it requires different diagnostic approaches and treatment considerations than Lyme disease. Babesia is a protozoan parasite, not a bacterium, and therefore does not respond to antibiotics used for Lyme disease. If Babesiosis is not specifically considered, appropriate testing and treatment may not be pursued.
Additionally, babesiosis can present with fluctuating or relapsing symptoms, and some individuals may have mild or initially asymptomatic infection. This variability can make timing and interpretation of testing more challenging.
For these reasons, clinical awareness and experience with tick-borne co-infections are important when evaluating individuals with ongoing or unexplained symptoms following tick exposure.
Symptoms of babesiosis can be nonspecific and overlap with those of Lyme disease, viral infections, anemia, or other inflammatory conditions. Fatigue, headaches, muscle pain, shortness of breath, and night sweats may be attributed to stress, post-viral syndromes, menopause, or residual Lyme symptoms rather than a parasitic infection.
Babesiosis may also be overlooked because it requires different diagnostic approaches and treatment considerations than Lyme disease. Babesia is a protozoan parasite, not a bacterium, and therefore does not respond to antibiotics used for Lyme disease. If Babesiosis is not specifically considered, appropriate testing and treatment may not be pursued.
Additionally, babesiosis can present with fluctuating or relapsing symptoms, and some individuals may have mild or initially asymptomatic infection. This variability can make timing and interpretation of testing more challenging.
For these reasons, clinical awareness and experience with tick-borne co-infections are important when evaluating individuals with ongoing or unexplained symptoms following tick exposure.
Testing for Babesiosis
Within the medical community, there are two recognized standards of care regarding the diagnosis of Lyme disease and other tick-borne diseases including babesiosis. Conventional guidelines from the Infectious Diseases Society of America (IDSA) recommend confirmation using a Giemsa-stained peripheral blood smear or polymerase chain reaction (PCR) testing.
Blood smear examination can directly visualize the parasite but is often limited by low levels of infected red blood cells. PCR testing detects Babesia DNA and can be useful in acute infection, though sensitivity may be reduced in chronic or relapsing presentations.
Some clinicians, including many affiliated with the International Lyme and Associated Diseases Society (ILADS), incorporate additional diagnostic technologies such as fluorescence in situ hybridization (FISH). FISH is a direct test that detects Babesia ribosomal RNA (rRNA) and can identify multiple species within the genus. Because RNA degrades rapidly in nonviable organisms, FISH may be helpful in detecting persistent infection.
For these reasons, testing decisions and interpretation are best guided by symptoms, exposure history, timing, and clinical judgment, in addition to the thoughtful use of laboratory testing.
Blood smear examination can directly visualize the parasite but is often limited by low levels of infected red blood cells. PCR testing detects Babesia DNA and can be useful in acute infection, though sensitivity may be reduced in chronic or relapsing presentations.
Some clinicians, including many affiliated with the International Lyme and Associated Diseases Society (ILADS), incorporate additional diagnostic technologies such as fluorescence in situ hybridization (FISH). FISH is a direct test that detects Babesia ribosomal RNA (rRNA) and can identify multiple species within the genus. Because RNA degrades rapidly in nonviable organisms, FISH may be helpful in detecting persistent infection.
For these reasons, testing decisions and interpretation are best guided by symptoms, exposure history, timing, and clinical judgment, in addition to the thoughtful use of laboratory testing.
Treatment Considerations for Babesiosis
Treatment considerations for babesiosis differ from those for Lyme disease because Babesia is a protozoan parasite rather than a bacterium. As a result, management requires parasite-specific therapies.
Within the medical community, there are differing perspectives on diagnosis and treatment of tick-borne diseases. Conventional guidelines from the Infectious Diseases Society of America (IDSA) recommend combination antimicrobial therapy, most commonly azithromycin and atovaquone. Studies recognize that longer treatment durations or retreatment may be required in certain cases.
For this reason, some clinicians affiliated with the International Lyme and Associated Diseases Society (ILADS) incorporate extended or layered treatment strategies. Longer and more complex treatment approaches, including the use of additional or novel therapies such as dapsone—which has been the subject of multiple published studies by Richard Horowitz—have been emphasized particularly in patients with persistent symptoms or co-infections.
In my clinical approach, treatment often includes an initial pharmaceutical phase, followed by a transition to targeted botanical therapies. Botanical medicine offers additional mechanisms of action against Babesia, including antiprotozoal activity, immune modulation, anti-inflammatory effects, and protection of red blood cells and the vascular system. One such formula is Bab Plus, which combines several botanicals commonly used in integrative approaches to babesiosis care and supported by research. Incorporating anti-biofilm interventions throughout the treatment plan is also essential.
Treatment decisions for babesiosis are highly individualized and depend on factors such as symptom severity, duration of illness, immune status, co-infections, and response to prior therapies. Ongoing monitoring and clinical judgment are essential throughout the course of care.
For clinicians and readers interested in a more in-depth, evidence-informed discussion of babesiosis, including diagnostic challenges and integrative treatment strategies, I have published a detailed article in Naturopathic Doctor News & Review (NDNR).
👉 The Diagnosis and Treatment of Babesiosis: A Naturopathic Approach to an Emerging Tick-Borne Disease
Within the medical community, there are differing perspectives on diagnosis and treatment of tick-borne diseases. Conventional guidelines from the Infectious Diseases Society of America (IDSA) recommend combination antimicrobial therapy, most commonly azithromycin and atovaquone. Studies recognize that longer treatment durations or retreatment may be required in certain cases.
For this reason, some clinicians affiliated with the International Lyme and Associated Diseases Society (ILADS) incorporate extended or layered treatment strategies. Longer and more complex treatment approaches, including the use of additional or novel therapies such as dapsone—which has been the subject of multiple published studies by Richard Horowitz—have been emphasized particularly in patients with persistent symptoms or co-infections.
In my clinical approach, treatment often includes an initial pharmaceutical phase, followed by a transition to targeted botanical therapies. Botanical medicine offers additional mechanisms of action against Babesia, including antiprotozoal activity, immune modulation, anti-inflammatory effects, and protection of red blood cells and the vascular system. One such formula is Bab Plus, which combines several botanicals commonly used in integrative approaches to babesiosis care and supported by research. Incorporating anti-biofilm interventions throughout the treatment plan is also essential.
Treatment decisions for babesiosis are highly individualized and depend on factors such as symptom severity, duration of illness, immune status, co-infections, and response to prior therapies. Ongoing monitoring and clinical judgment are essential throughout the course of care.
For clinicians and readers interested in a more in-depth, evidence-informed discussion of babesiosis, including diagnostic challenges and integrative treatment strategies, I have published a detailed article in Naturopathic Doctor News & Review (NDNR).
👉 The Diagnosis and Treatment of Babesiosis: A Naturopathic Approach to an Emerging Tick-Borne Disease
Babesiosis and Co-Infections
Babesiosis frequently occurs alongside other tick-borne infections, particularly Lyme disease, because the same ticks can transmit multiple pathogens during a single bite. As a result, co-infection is common in endemic areas.
When babesiosis is present with Lyme disease, symptoms may be more persistent or atypical, and patients will not fully improve with Lyme-directed treatment alone. In these cases, unrecognized babesiosis can contribute to ongoing symptoms.
For this reason, consideration of co-infections is an important part of a comprehensive tick-borne disease evaluation, particularly when symptoms persist or relapse.
👉 Learn more about Lyme disease and other tick-borne diseases
When babesiosis is present with Lyme disease, symptoms may be more persistent or atypical, and patients will not fully improve with Lyme-directed treatment alone. In these cases, unrecognized babesiosis can contribute to ongoing symptoms.
For this reason, consideration of co-infections is an important part of a comprehensive tick-borne disease evaluation, particularly when symptoms persist or relapse.
👉 Learn more about Lyme disease and other tick-borne diseases
Who Is at Higher Risk of Severe Illness?
The severity of babesiosis can vary widely. While some individuals experience mild or asymptomatic infection, others are at higher risk for more severe or prolonged illness.
Risk factors associated with more severe babesiosis include age over 50, absence of a functioning spleen, immune compromise, and co-infection with other tick-borne diseases such as Lyme disease. Individuals with underlying medical conditions may also experience more complicated disease courses.
In babesiosis, red blood cell infection may increase the risk of complications such as hemolytic anemia and impaired oxygen delivery. Early recognition and individualized care are particularly important in these populations.
Mast cell activation may further complicate recovery in some individuals. Learn more about MCAS.
Risk factors associated with more severe babesiosis include age over 50, absence of a functioning spleen, immune compromise, and co-infection with other tick-borne diseases such as Lyme disease. Individuals with underlying medical conditions may also experience more complicated disease courses.
In babesiosis, red blood cell infection may increase the risk of complications such as hemolytic anemia and impaired oxygen delivery. Early recognition and individualized care are particularly important in these populations.
Mast cell activation may further complicate recovery in some individuals. Learn more about MCAS.
Prevention and What to Do After a Tick Bite
Preventing tick bites and responding promptly after exposure can help reduce the risk of babesiosis and other tick-borne infections. Babesia may be transmitted relatively quickly after a tick bite, making early awareness and informed action important.
Timely tick removal, documentation of exposure, and symptom monitoring over time are key steps following a bite, even if symptoms are initially absent.
For a detailed, step-by-step guide on next steps after a tick bite, visit:
👉 What to Do After a Tick Bite
Timely tick removal, documentation of exposure, and symptom monitoring over time are key steps following a bite, even if symptoms are initially absent.
For a detailed, step-by-step guide on next steps after a tick bite, visit:
👉 What to Do After a Tick Bite
Schedule a Consultation
If you are seeking individualized guidance related to babesiosis or other tick-borne illnesses, appointments are available to support education, evaluation, and next steps. Care is tailored to each individual’s circumstances and may include an in-depth discussion, review of symptoms and history, recommendations and coordination with other healthcare providers when appropriate.
Telehealth consultations are available and allow individuals to access support from home, which can be especially helpful for those experiencing fatigue, neurological symptoms, or limited access to specialized care. Specific services available through telehealth depend on location and licensure and are reviewed in detail during the intake and consent process to ensure clarity and transparency.
To learn more about scheduling options or to request an appointment, please visit:
👉 Schedule an Appointment
Taking the next step begins with understanding your options and determining what support may be most appropriate for you.
Telehealth consultations are available and allow individuals to access support from home, which can be especially helpful for those experiencing fatigue, neurological symptoms, or limited access to specialized care. Specific services available through telehealth depend on location and licensure and are reviewed in detail during the intake and consent process to ensure clarity and transparency.
To learn more about scheduling options or to request an appointment, please visit:
👉 Schedule an Appointment
Taking the next step begins with understanding your options and determining what support may be most appropriate for you.
All material provided on this website is provided for informational or educational purposes only,
and is not intended as a substitute for the advice provided by your physician or healthcare professional.