HARRISBURG, Pa. (WHTM) – Babesia microti is a parasite that can be contracted from a tick bite. If you have Babesia and donate blood, you can pass it to someone else. The parasite can be deadly if not treated. So far, it has been linked to four deaths from blood transfusions.

An article entitled “Screening for Babesia microti in the U.S. Blood Supply” was published in the New England Journal of Medicine. The article is based on a study done by the American Red Cross.

Right now, Babesia microti is prevalent in the New England states, which is where the American Red Cross conducted its two-year study of blood donations. The study found 29 cases where Babesia was transmitted through infected donors

“It is scary,” said Rita Rhoads, a nurse practitioner at Integrative Health Consults.

Rhoads specializes in tick-borne illnesses and says Babesia cases from tick bites at her practice are on the rise, which is why she finds the study of Babesia microti in the blood supply concerning. Of the 89,153 blood donations that were screened by the American Red Cross, 335 were found positive for Babesia.

“I think 300 and some cases over two years is significant,” Rhoads said. “If I am the person who gets Babesia from that donated blood, I am going to be very upset.”

“I would take away from a report like this how incredibly safe the blood supply is,” said Dr. John D. Goldman, an infectious disease specialist at UPMC PinnacleHealth.

Goldman also treats patients who have contracted Babesia from a tick bite but says he has had only a handful of cases.

“So even though 335 cases sounds like a big number, when you think of all the units of blood that are transfused per units, that is extremely low. Probably it’s the equivalent of getting struck by lightning,” Goldman said.

According to the American Red Cross report, areas affected by Babesia microti are expanding. The Centers For Disease Control and Prevention publishes statistics for Babesia on its website. There are no statistics for Pennsylvania. The Pennsylvania Department of Health says while physicians report cases to the department, it is not a considered a reportable disease so it doesn’t keep statistics or pass the numbers onto the CDC.

“If Pennsylvania is not forwarding the reports that we forwarded to them, nobody can get a handle on it,” Rhoads said.

Right now, potential blood donors are asked if they have ever had Babesia. If they answer yes, they cannot donate. But some donors may not know they have the parasite. Currently, there is no FDA-approved test to screen the blood supply for Babesia.

“It is such a rare disease that you are really ending up testing for something that almost never occurs,” Goldman said. “[Testing would] probably be cost ineffective and you would probably get enough false positives, meaning the test is wrong.”

“I really would like to see them testing for all forms of Babesia and then see what the statistics are, but it really doesn’t matter. If it is only 1,000 cases in the blood supply, that’s too many,” Rhoads said.

The American Red Cross is currently conducting another study of Babesia microti in the blood supply that includes Pennsylvania. The study should be completed this year. The results will be shared with the FDA.

Symptoms of Babesia :

According to the CDC, many people who are infected with Babesia microti feel fine and do not have any symptoms. Some people develop flu-like symptoms, such as fever, chills, sweats, headache, body aches, loss of appetite, nausea, or fatigue. It can also causehemolytic anemia, because Babesia parasites infect red blood cells.

Babesiosis can be a severe, life-threatening disease, particularly in people who:

  • do not have a spleen;
  • have a weak immune system for other reasons (such as cancer, lymphoma, or AIDS);
  • have other serious health conditions (such as liver or kidney disease); or
  • are elderly.

Babesia Treatment:

For ill patients, babesiosis usually is treated for at least 7-10 days with a combination of two prescription medications – typically either:

  • atovaquone PLUS azithromycin; OR
  • clindamycin PLUS quinine (this combination is the standard of care for severely ill patients).

What you can do:

People who have a scheduled surgery can donate their own blood ahead of time which can eliminate the chance of infection from transfusion.



Pa. Lyme Resource Network 

Lyme Disease.org