Archive for the ‘Babesia’ Category

Emerging Tick-Borne Diseases & Blood Safety: Summary of a Public Workshop

. 2020 Mar 24.

doi: 10.1111/trf.15752. Online ahead of print.

Emerging Tick-Borne Diseases and Blood Safety: Summary of a Public Workshop

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Tick-borne agents of disease continue to emerge and subsequently expand their geographic distribution. The threat to blood safety by tick-borne agents is ever increasing and requires constant surveillance concomitant with implementation of appropriate intervention methods. In April 2017, the Food and Drug Administration organized a public workshop on emerging tick-borne pathogens (excluding Babesia microti and Lyme disease) designed to provide updates on the current understanding of emerging tick-borne diseases, thereby allowing for extended discussions to determine if decisions regarding mitigation strategies need to be made proactively. Subject matter experts and other stakeholders participated in this workshop to discuss issues of biology, epidemiology, and clinical burden of tick-borne agents, risk of transfusion-transmission, surveillance, and considerations for decision making in implementing safety interventions. Herein, we summarize the scientific presentations, panel discussions, and considerations going forward.



I only had access to the abstract, but Dr. Cameron writes more fully on the workshop here:

Interestingly, according to the abstract, they excluded Babesia and Lyme, which are arguably two of the largest problems. It was pointed out that 200 cases of Babesia were transmitted through blood transfusions at the time of the workshop and that Anaplasma is next with increasing clinical cases.

Evidently there have been no reported cases of Lyme transmitted through the blood supply.


Other tick-borne pathogens have been transmitted through donated blood, but these occurrences are rare. (Or rarely reported)

  • 11 cases: A. phagocytophilum, responsible for Anaplasmosis (transmitted by the Ixodes ticks)
  • 2 cases: Tick-borne encephalitis virus complex (TBEV, Powassan virus, DTV), (transmitted by the Ixodes ticks)
  • 1 case: Colorado tick-fever virus (transmitted by Rocky Mountain wood ticks)
  • 1 case: Rickettsia rickettsii, the agent of Rocky Mountain Spotted Fever (transmitted by the Lone Star tick)
  • 1 case: Ehrlichia ewingii (transmitted by the Lone Star tick)

In addition, “two emerging [tick-borne agents] − B. miyamotoi and Powassan virus were discussed − for B. miyamotoi,cases have steadily increased since 2014.”

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Babesia Microti Imported Into Foreign Countries


Man with babesia microti infection travelling with suitcase

Over the past two decades, there have been reports of the tick-borne infection Babesia microti being imported into foreign countries from the United States. International travelers are unknowingly carrying the disease into countries, which may be unfamiliar with diagnosing tick-borne illnesses.

“Recently, sporadic cases of human babesiosis caused by several species of Babesia have been reported in other countries,” write the authors of “Imported Human Babesiosis, Singapore, 2018.” [1] These cases include:

  • Babesia microti (Germany, Australia, South Korea)
  • Babesia microti-like (Japan, Taiwan, China)
  • Babesia duncani (United States, Canada)
  • Babesia divergens (Europe)
  • Babesia venatorum (Europe, China)
  • Babesia crassa-like (China)
  • Babesia motasi-like (South Korea)

Additionally, in 2003, Nohýnková and colleagues reported what was believed to be the first case of symptomatic Babesia microti infection imported into the Czech Republic from the United States. [2] Meanwhile in 2013, investigators described the “first human case of Babesia microti infection imported to Denmark from the United States by a 64-year-old female traveler with fever of unknown origin.” [3]

READ MORE: Tourists visiting the United States contract Babesia, leaving one dead

According to the authors, “The case raises the possibility that Babesia infections may be under-diagnosed, [and] illustrates the importance of a thorough travel history…” [3]

The number of international travelers carrying tick-borne diseases into foreign countries is rising, making it increasingly important for clinicians to gather a thorough travel history on patients. CLICK TO TWEET 

Two recent case reports demonstrate the rise of tick-borne diseases being imported into other countries and highlights the challenges clinicians face in distinguishing these illnesses, specifically Babesia microti, from malaria.

Case 1: Singapore

A 37-year-old man traveled to multiple places in the year before his illness. His travel history included Vietnam, Thailand, Indonesia, Cambodia, Indonesia, and the United States.

On June 17, 2018, after visiting the Northeastern USA, he noted a right ankle papule that lasted 3 weeks. “He sought consultation at a travel clinic [in Singapore] because of high fever (104°F), rigors, and headaches, which had persisted and worsened over 18 days,” writes Lim and colleagues. [1]

Doctors had prescribed amoxicillin, but the symptoms persisted.

LISTEN TO PODCAST: Babesia treatment of two travelers

“Laboratory test results revealed moderate thrombocytopenia and anemia, and malaria blood films revealed trophozoites forming in erythrocytes, suggestive of Babesia,” writes Lin.

The doctors confirmed the diagnosis of Babesia microti with additional testing. He was treated successfully with quinine and clindamycin.

Case 2: Spain

“A 72-year-old man with a 15-day history of fever, generalized arthralgia, asthenia, and decreased appetite was admitted to Hospital Universitario San Cecilio, Granada, Spain,” writes Guirao-Arrabal and colleagues in “Imported babesiosis caused by Babesia microti − A case report.” [4]

The man had a history of sweating and his inflammatory markers were elevated. He also had a history of type 2 diabetes.

He reportedly traveled to a park in Westchester County, NY, an area that is considered endemic for babesiosis.

Malaria was considered based on intraerythrocytic forms in the red cells. The malaria antigen and PCR tests for malaria were negative.

Babesia microti was presumed with a low level of parasitemia (0.5 %). There was no evidence of another tick-borne illness. After treatment with atovaquone and azithromycin, his parasitemia resolved.

Editor’s note: It is encouraging to see that Babesia is now being considered by clinicians and treated appropriately.


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Babesia Infection 3 Weeks After Lyme Treatment


A Babesia infection 3 weeks after treatment for Lyme disease.

I will discuss a 67-year-old woman with a Babesia infection 3 weeks after treatment for Lyme disease. Could this delay explain why some patients remain ill or relapse?


Hoversten and her colleague first discussed this case in the British Medical Journal Case Reports  in 2018.

One would expect that tick-borne infections would all occur at the same time.

One would be wrong, as this case illustrates.

A 67-year-old woman from Wisconsin had extensive exposure as an avid gardener and spent a considerable amount of time outdoors.

She did not see a tick. She did see a rash consistent with an erythema migrans rash.

A delay in onset of Babesia may explain why some Lyme disease patients relapse after initially improving with doxycycline or amoxicillin. CLICK TO TWEET

She was prescribed amoxicillin for three-weeks as she was allergic to doxycycline.

Near the end of three-week of amoxicillin, she became ill. Her fever rose to 102.9 F0. She complained of myalgias, dizziness, and fatigue.

Her blood test showed mild anemia, a low platelet count and neutrophil count, and a very high C-reactive protein.

  • neutrophil is a type of white blood cell that helps resolve infections and heal damaged tissues. A low neutrophil count can be seen in tick-borne diseases.
  • A high C-reactive protein is a marker for inflammation but cannot be used to determine what type of inflammation.

She was admitted to the hospital. The doctors thought she might be suffering from sepsis or a tick-borne infection.

  • Sepsis is a life-threatening illness caused by your body’s response to an infection.
  • Her red blood count and platelets continued to drop.
  • She was transferred to a second hospital.
  • There was no evidence of sepsis. The blood cultures were negative after five days.


She was diagnosed with the parasite Babesia microti by PCR and by a thin smear of her red blood cells. Typically, Babesia microti is seen on a thick smear of blood. In her case, 0.4% of her red blood cells showed the parasite Babesia microti on a thin smear.

Babesia infections can be severe and, in rare cases, life-threatening. Babesia infections can also be mild or without symptoms. Babesia was more likely to be severe in this woman as she was over 50-years of age and had a history of colon cancer.

She was prescribed a 10-day course of azithromycin and atovaquone. By 5th day of treatment, her fever had resolved, and her platelet count had more than doubled from a low of 17,000 per dl to 42, 000 per dl.

The authors report that the woman remains fatigued after completing treatment.

The authors discussed the nearly three-week gap in time between the woman’s erythema migrans rash and her diagnosis of Babesia. This is not the first case where the onset of Babesia was delayed.

The authors cited two papers describing a 3 to 4-week delay in the onset of Babesia. I described a paper in an earlier podcast where two babies contracted Babesia from their mothers. They did not present with Babesia until after being discharged from the hospital. You can read more about these babies in the article by Saetre and colleagues or listen to my Inside Lyme podcast titled. “Two children who contacted Babesia from their mother.”

This delay may explain why some Lyme disease patients relapse after initially improving with doxycycline or amoxicillin. Treatment for Lyme disease with doxycycline or amoxicillin is not effective for the treatment of Babesia.

What can we learn from this cases?

  1. Babesia infections can occur weeks after the onset of Lyme disease.

What questions does these cases raise?

  1. Should the woman have been evaluated for Babesia infection at the time of the erythema migrans?
  2. Would a Babesia infection have been recognized if the woman had not been diagnosed with Lyme disease?
  3. Should Lyme disease patients be advised to return for follow-up?
  4. Would earlier treatment have avoided the need for hospitalization?
  5. What is the long-term outcome for this woman with a Babesia infection


In my practice, each individual requires a careful assessment. That is why I order a broad range of blood tests for other illnesses in addition to tick-borne infections. I also arrange consultations with specialists as needed.

Many patients are complex, as highlighted in this Inside Lyme Podcast series.

We need more doctors with skills recognizing Babesia in a patient with Lyme disease. We hope that professionals evaluating individuals with Lyme disease can use this case to remind them to look for Babesia with Lyme disease.

Inside Lyme Podcast Series

This Inside Lyme case series will be discussed on my Facebook and made available on podcast and YouTube.  As always, it is your likes, comments, and shares that help spread the word about this series and our work. If you can, please leave a review on iTunes or wherever else you get your podcasts.

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Babesia Infections Explode In Hudson Valley, NY


man sick with babesia infection

Babesia, a parasitic infection usually transmitted through a tick bite, was once thought to be a coastal tick-borne disease limited to Suffolk County on Long Island. Some doctors had been reluctant to acknowledge that Babesia could be found in other locations. But in 2001, Babesia infections were reported in lower Hudson Valley, New York, a region north of Manhattan and has since continued to spread with an increase in the number of cases far beyond the borders of Long Island.

In their article “Increasing incidence and changing epidemiology of babesiosis in the Hudson Valley region of New York State: 2009-2016,” ¹ Joseph and colleagues question how cases of Babesia infections are spreading given that the animal reservoirs mice, shrews, and voles typically do not travel large distances.
Cases of Babesia have been reported in two counties located east of the Hudson River: Dutchess County and Westchester County, the authors write. (Westchester County alone has a population of nearly 1 million residents.)

Read More: Babesia remains a clinical diagnosis for some patients.

But since 2009, there has been an explosion of Babesia infections in the Upper Hudson Valley, New York region. This area consists of Albany County, Columbia County, Greene County, and Rensselaer County.

Over an 8-year period (between 2009-2016), there was a 16.8-fold increase in the incidence of Babesia cases in the Upper Hudson Valley region.

The number of Babesia cases explodes in the upper Hudson Valley, NY region. CLICK TO TWEET

The number of cases also increased in the Lower Hudson Valley region, which consists of Dutchess County, Putnam County, Westchester County, Orange County, Rockland County, Sullivan County, and Ulster County.

The actual number of Babesia cases is likely higher:

  1. It was not until 2011, that the Centers for Disease Control and Prevention (CDC) made Babesia a reportable disease. Between 2011 and 2016, New York State had a reported 2,750 cases of Babesia, the highest number in any state in the U.S.
  2. Babesia can be difficult to identify since the parasites in the red blood cells can quickly clear.
  3. Lastly, Babesia cases may not be recorded if the physician does not report the case to the CDC.

“In conclusion, babesiosis is a rapidly emerging infection in the Hudson Valley region of New York State, the geographic region now accounting for more cases than any other single geographic area in the state,” the authors write.

Therefore, “clinicians caring for patients with symptoms compatible with babesiosis, who live in or have traveled to the Hudson Valley region of New York State, should consider the possibility of babesiosis.”

Editor’s Note: I have practiced medicine in the Hudson Valley, New York region for more than 33 years. I have treated patients with Babesia infections for the past three decades. Many of the first patients first described with Babesia were caught early when Babesia microti was seen in the red blood cells. I typically diagnose cases of Babesia with a positive antibody test or using clinical judgment.

In addition, the authors addressed Babesia microti in their paper. I have seen evidence that Babesia duncani appears to be a problem in the area. Babesia duncani was first identified on the West Coast. We need more research on this tick-borne disease.

Lastly, the presence of Babesia has important treatment considerations. Neither doxycycline nor amoxicillin are effective in treating Babesia. Patients with Lyme disease, co-infected with Babesia, would need a combination of antimicrobials to include an anti-parasitic medication (i.e., azithromycin combined with Atovaquone).

Frequency & Magnitude of Seroreactivity to Babesia Microti in 245 Patients Diagnosed by PCR in N.Y. State

2020 Jan 29:115008. doi: 10.1016/j.diagmicrobio.2020.115008. [Epub ahead of print]

Frequency and magnitude of seroreactivity to Babesia microti in 245 patients diagnosed by PCR in New York State.


Multiple methodologies have been used to detect antibodies to Babesia microti. Use of an indirect immunofluorescence assay (IFA) has been the most widely used approach, but IFAs have varied as to which antibody class or classes are being detected and in regard to cutoff titers. In this study, 245 different patients with polymerase chain reaction (PCR)-confirmed B. microti infection were tested by a polyvalent IFA using serum collected within 3 days of the date the blood sample for PCR testing was obtained. Of the 245 patients, 243 (99.2%) had a positive serologic test result (i.e., ≥1:64). Of the 243 patients who were seropositive, 242 (99.6%) had a titer of ≥1:256, 236 (97.1%) had a titer of ≥1:512, and 210 (86.4%) had a titer of ≥1:1024. In conclusion, high titer seropositivity based on a polyvalent IFA is to be expected at the time of PCR confirmation of active babesiosis in clinical practice.


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