Babesia Blood Safety: What the FDA Workshop Revealed

Babesia blood safety is a growing concern in the United States. In their article, the authors summarized discussions from a public workshop organized by the Food and Drug Administration (FDA). The workshop, entitled “Emerging Tick-Borne Diseases and Blood Safety,” included experts on tick-borne diseases, representatives from blood centers, academia, government agencies, and manufacturers of diagnostic kits.

The workshop’s goal was to review emerging tick-borne diseases within the US and discuss whether new blood safety measures should be implemented.

Babesia Blood Safety: The Biggest Threat

As one attendee pointed out, Babesia microti infections have been the biggest problem for the blood supply to date. In fact, there were over 200 cases of Babesia microti infection transmitted through blood transfusion in the US at the time of the workshop.

Babesia microti can have moderate to high concentration levels in the blood, Dr. Peter J. Krause pointed out.

Aside from Babesia, “Anaplasma is the most frequent transfusion-transmitted [tick-borne agent] with rapidly increasing clinical cases,” according to one attendee.

Babesia microti is currently the highest-ranked pathogen transmitted by blood transfusions. The infection can go undetected as healthy individuals may be asymptomatic or symptoms are subtle. But for others, it can cause chronic, debilitating illness.

Lyme Disease and Blood Supply

In contrast, Borrelia burgdorferi, the bacteria that causes Lyme disease, has low concentrations in the blood.

And although B. burgdorferi can survive in fresh frozen plasma, RBCs, and platelets during blood storage, there have been no reported cases of Lyme disease transmitted through the blood supply.

Other Tick-Borne Agents in Blood

Other tick-borne pathogens have been transmitted through donated blood, but these occurrences are rare:

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

The threat to babesia blood safety by tick-borne agents is ever-increasing.

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

But we still have much to learn. “B. miyamotoi, [responsible for tick-borne relapsing fever] is present in higher-titers in blood compared to B. burgdorferi, yet there are no cases of B. miyamotoi transmitted by blood.”

Screening Donors for Babesia Blood Safety

By screening donors, America’s Blood Centers have been able to reduce some transfusion-transmitted infections, such as HIV, Hepatitis B virus, and Malaria.

Between 1963 and 2013, there were reportedly 99 cases of malaria transmitted through blood transfusions. The majority occurred before 2000. But since 2000, the rates fell to less than 1 case per year, the authors explain.

Unfortunately, the screening process doesn’t always work. Studies have found that “donor responses to a history of tick-bites and donor responses to a history of babesiosis and Chagas” had no correlation to infection with tick-borne agents.

This is why some patients only discover their infection through blood donation screening—and why improving babesia blood safety remains a priority.

Frequently Asked Questions

Can you get Babesia from a blood transfusion?

Yes. Over 200 cases of transfusion-transmitted Babesia have been reported in the US. It is currently the highest-ranked pathogen transmitted through blood transfusions.

Is Lyme disease transmitted through blood transfusions?

No. Although Borrelia burgdorferi can survive in stored blood products, there have been no reported cases of Lyme disease transmitted through the blood supply.

Does donor screening prevent Babesia transmission?

Not reliably. Studies show that asking donors about tick bites or history of babesiosis does not correlate with actual infection. More advanced testing is needed.

What other tick-borne diseases can be transmitted through blood?

Anaplasmosis (11 cases), tick-borne encephalitis viruses (2 cases), and rare cases of Rocky Mountain Spotted Fever and Ehrlichia have been reported.

Why is Babesia a bigger blood safety threat than Lyme disease?

Babesia microti has moderate to high concentrations in blood, while B. burgdorferi has low concentrations—making Babesia more likely to survive and be transmitted through transfusion.