Babesia and Lyme disease may occur as co-infections which can cause worse symptoms than either disease in isolation and can complicate diagnosis and treatment. Babesia is, however, a protozoan parasite rather than a bacterium like Borrelia burgdorferi, and this infection of the blood causes a haemolytic disease (Babesiosis) producing symptoms similar to malaria. Unfortunately, this difference in pathogen means that Lyme disease antibiotics do not treat Babesiosis, making accurate diagnosis of both infections extremely important.
There are over a hundred species of Babesia but only a few of these are thought to be implicated in the development of Babesiosis symptoms in humans. The most common of these strains to affect humans in the United States is Babesia microti; other species of Babesia affect cattle and livestock, along with domestic animals such as dogs and cats. The second most common is Babesia divergens and, although other strains have been found to infect humans, these two strains are the ones most commonly seen in practice.
Babesiosis was first documented in the late 1800s as a disease of cattle and sheep by the Romanian scientist Victor Babes, hence the name Babesia. Babes actually identified a different organism however but his suspicion that the infection was passed on by tick bite was confirmed by subsequent scientists. Human infection with Babesiosis was only documented in 1957 in a patient who had had their spleen removed. Cases after this initial incident also occurred exclusively in splenectomized patients for many years but the first case in a patient who had not undergone splenectomy occurred in 1969 and showed that Babesia could be pathogenic to all humans.
Unlike Lyme disease transmission, Babesia can be passed on through blood transfusions meaning that blood donations require testing using IFA. The Centers for Disease Control have acknowledged more than forty cases of Babesiosis resulting from packed red blood cell transfusions, as well as infections occurring after organ transplants.
Diagnosing Babesiosis, which may also be referred to as Piroplasmosis, Redwater Fever, Tick Fever, Nantucket Fever, and Texas Cattle Fever, requires a blood test to detect the presence of the parasite in a blood smear, along with an indirect fluorescent assay (IFA) which has a higher specificity for Babesia. The use of blood smears alone can cause confusion due to the similarities between the malarial parasite and Babesia. Up until recently, xenodiagnosis using hamsters was popular to detect the presence of the protozoa in a =”patient’s blood sample but faster testing methods have largely replaced this technique. Conversely, xenodiagnosis for Lyme disease has recently been proposed as an alternative testing method, especially for chronic Lyme disease cases.
Chronic Lyme Disease or Babesiosis Co-infection?
On the face of things it would be unusual for Babesia to be incorrectly diagnosed as Lyme disease as it is more likely to be mistaken for malaria, but there is some symptom overlap. The presence of Babesiosis can definitely complicate Lyme disease diagnosis and treatment especially if symptoms of Lyme disease persist after treatment. In such cases it is wise to test for Babesiosis and Lyme disease co-infections.