Babesia/Theileria species are closely related apicomplexan protozoa that infect red blood cells. The infection they cause is called babesiosis.
The group they belong to is called “apicomplexan” because of a special group of organelles (small parts of a bacteria) that make it easier for them to get inside of other cells. Once inside of red blood cells, they increase in number (replicate). Eventually they cause lysis, a process where the cell breaks open and spills the newly replicated protozoa into the bloodstream.
Babesia/Theileria are similar to another member of the apicomplexan family, the Plasmodia species, which are the pathogens that cause malaria. Malaria has been widely studied, and this research helps scientists understand babesiosis better.
Babesia microti is the primary cause of babesiosis in the United States. The CDC reports that most cases occur in the Northeastern and Midwestern regions, with the highest incidence occurring in states such as New Jersey, New York, and Wisconsin. Like Lyme disease, Babesia microti are being found in more and more regions. In fact, studies suggest that the presence of Lyme disease makes an ecosystem more susceptible to the establishment of Babesia microti.
Babesia duncani infection has also been documented in the United States, but primarily on the Pacific coast. In Canada, a recent study found that Babesia duncani was widespread, with most cases being along the Pacific coast of North America. Babesia divergens is another causative agent of babesiosis, but it has been primarily documented in Europe.
Transmission
Babesia/Theileria species are primarily transmitted to humans via bites from infected Ixodes ticks. Ticks become infected when they feed on mammals infected with the protozoa (mammalian reservoirs). The primary mammalian reservoir for Babesia microti is the white-footed mouse, but it has been found in shrews, chipmunks, and voles as well.
The primary tick vector for Babesia/Theileria species is Ixodes scapularis, which have also been shown to transmit co-infections like Borrelia (Lyme borreliosis) and Anaplasma species. People that have outdoor occupations or spend time outdoors in endemic areas are at a higher risk of babesiosis.
Research has also shown that Babesia/Theileria species can be transmitted through blood transfusions. In one study involving an infected Minnesota blood donor, evidence of new Babesia microti infection occurred in four patients who received donations of his red blood cells or platelets.
Symptoms
The non-specific and chronic symptoms associated with babesiosis often mimic other chronic infections and autoimmune diseases. The clinical presentations can range from mild to a malaria-like illness. Being aware of a recent tick attachment and whether Babesia is endemic to the region is helpful for diagnosis.
A list of common, but not all, symptoms of babesiosis can be seen below:
- High fever
- Headache
- Muscle aches
- Loss of appetite
- Nausea
- Fatigue
- Swelling of the liver/spleen
- Anemia
The clinical signs for patients who are immunocompromised or have co-infections may be more severe.
Galaxy Diagnostics Testing – Babesia/Theileria Species
Galaxy’s Babesia/Theileria species (spp.) PCR test is designed to detect active infection of pathogenic Babesia/Theileria species. Polymerase chain reaction (PCR) is a common method used by clinical labs and researchers to detect DNA fragments in a sample.
The broad-spectrum PCR primers (small pieces of DNA) that we designed can detect Babesia/Theileria at the genus level, rather than focusing on a single species. This is useful because babesiosis can be caused by multiple species that cause variable, non-specific symptoms.
If DNA is detected, positive results are confirmed with DNA sequencing. DNA sequencing is used to analyze the detected DNA and determine what species is present. This means there is a very low chance of a false positive. There is always a risk of false negatives because of the nature of these pathogens, so Galaxy does recommend re-testing if symptoms persist following a negative result.
Testing should always be discussed with a licensed physician and considered on a case-by-case basis.
Test Requirements:
This test requires 3 mL of whole blood in a lavender-top (EDTA) tube. No fasting required.
Antimicrobial treatments may increase or decrease test targets in patient samples. However, in the absence of scientific data, we are unable to provide guidance on how these treatments may affect PCR test methods. We leave this up to the discretion of the practitioner ordering the test who may consider if the clinical situation warrants any change in treatment before testing. Unless specifically directed by the practitioner ordering the test, do not change your treatment regimen before testing.
References
Lau, A. O. T. (2009). An overview of the Babesia, Plasmodium and Theileria genomes: A comparative perspective. Molecular and Biochemical Parasitology, 164(1), 1-8. doi:https://doi.org/10.1016/j.molbiopara.2008.11.013 https://www.sciencedirect.com/science/article/pii/S016668510800279X
Centers for Disease Control and Prevention. (2018). Parasites – Babesiosis general information. Retrieved from: https://www.cdc.gov/parasites/babesiosis/gen_info/index.html
Dunn, J. M. et al. (2014). Borrelia burgdorferi promotes the establishment of Babesia microti in the northeastern United States. PLoS One, 9(12), e115494. doi:10.1371/journal.pone.0115494 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4278703/
Scott, J. D., & Scott, C. M. (2018). Human Babesiosis caused by Babesia duncani has widespread distribution across Canada. Healthcare, 6(2), E49. doi:10.3390/healthcare6020049 https://www.ncbi.nlm.nih.gov/pubmed/29772759
Herwaldt, B. L. et al. (2002). Transmission of Babesia microti in Minnesota through four blood donations from the same donor over a 6-month period. Transfusion, 42(9), 1154-1158. https://www.ncbi.nlm.nih.gov/pubmed/12430672
