Asymptomatic Babesia: Hidden Infections in Healthy Individuals
Asymptomatic Babesia infections may be far more common than realized. The number of individuals in the US who are unaware they are infected with Babesia could be significant.
At least 300,000 people are diagnosed with Lyme disease every year in the US. Up to 40% of those with Lyme disease in the Northeast may also be co-infected with Babesia.
In fact, Linden and colleagues from the Wadsworth Center, New York State Department of Health found that both community-acquired babesiosis and transfusion-transmitted babesiosis (TTB) increased significantly over a 12-year period. The geographic range of ticks and tick-borne infections also expanded.
Asymptomatic Babesia Cases Rising in New York
In 2004, there were 91 cases of community-acquired Babesia, compared to 576 cases in 2015.
Overall, 3,799 cases of babesiosis were reported in New York during the study period. Fifty-five individuals acquired Babesia through blood transfusions from donors who were unaware they were infected.
More than half of the transfusion recipients were 60 years of age or older.
The donors only discovered they were infected after recipients became ill. In some cases, repeat donations from the same donor led to multiple infections.
When Do Asymptomatic Donors Give Blood?
Approximately 50% of donations occurred between July and September, when Ixodes scapularis tick activity peaks.
However, at least one implicated donation occurred in every month of the year, highlighting the year-round risk.
Most donors lived in endemic regions, particularly New York, but cases were also linked to donors from New Jersey, Massachusetts, Rhode Island, Pennsylvania, and Connecticut.
The Urgent Need for Babesia Screening
The need for effective blood donor screening is critical. Two transfusion recipients died from Babesia infection.
Currently, no universally licensed screening test is available in all regions.
Additionally, testing for B. microti may not detect other Babesia species or co-infections such as Anaplasma phagocytophilum, which can cause similar symptoms.
These findings highlight a serious public health concern: asymptomatic carriers can unknowingly transmit infection through the blood supply.
Clinical Takeaway
Asymptomatic Babesia infections are common and often undetected. Clinicians should consider Babesia in at-risk patients and remain aware of transfusion-related transmission risks.
References
- Linden JV, Prusinski MA, Crowder LA, et al. Transfusion-transmitted and community-acquired babesiosis in New York, 2004 to 2015. Transfusion. 2018.
- Diuk-Wasser MA, Vannier E, Krause PJ. Coinfection by Ixodes Tick-Borne Pathogens. Trends Parasitol. 2015.
Related Reading
- Babesia and Lyme: What Patients Need to Know
- Babesia Blood Donation: When Screening Finds Infection
- Transfusion-Transmitted Babesiosis
Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.
Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention
I had a strange attack, after being fatigued for the first time in my life. I had no energy, my left leg and arm are numb and don’t work well, brain fog, headaches for the first time in my life, facial numbness, trouble speaking sometimes, deteriorating eyesite, formication horribly, ringing in my ears and severe muscle weakness and muscle wasting and atrophy. Though I’m an avid outdoorsman, my doctors all ignored this information and focused on MS, myositis and other disorders. I showed antibodies for lyme, but refused to treat me though I told them I believed I possibly contracted lyme around a year and a half earlier, which is about 4 yrs ago now. I finally tested positive last November and was given 3 weeks of doxy which did absolutely nothing. My myelin sheaths have been damaged, found in a lumbar puncture and doctors just seem to stop treating and/or testing me. I truly need someone that will run the tests needed and treat me accordingly. Where can I get this help? I’m in upstate new york. I’m honestly on my last leg on this.
Thanks for sharing your story. Many of my patients in my New York Practice face the same uncertainty. It would seem reasonable to look at a tick borne illness a second time for other approaches that a single 3 week course of doxycycline.
Is it possible to transmit Babesia in plasma products such as IVIG or sub-q IG products?