Alternative Names: 

Human Babesiosis, Babesiosis IgG & IgM

What is Babesiosis and how is it transmitted?

Babesiosis is an infection caused by the parasite Babesia microti. The infection is acquired by contact with Ixodes ticks carrying the parasite. The deer mouse is the animal reservoir and, overall, the epidemiology of this infection is much like that of Lyme disease. Infectious forms are injected during tick bites and the organism enters the vascular system where it infects red blood cells (RBCs). Reproduction occurs in RBCs, and daughter cells are formed which are liberated on rupture (hemolysis) of the RBC.

Where is the infection prevalent?

Babesiosis is most prevalent in the Northeast, Upper Midwest, and Pacific Coast of the United States.

Severity of Babesiosis:

Most cases of babesiosis are probably mild, but the infection can be severe and life threatening, especially in older or asplenic patients (=without a functional spleen).

What are some of the Symptoms?

• Fever
• Fatigue
• Malaise (=weakness, discomfort and a feeling like you have an illness)
• Headache,
• Flu-like symptoms

In the most severe cases, hemolysis (=rupturing of red blood cells), acute respiratory distress syndrome, and shock may develop. Patients may have hepatomegaly (condition of having an enlarged liver) and splenomegaly (enlargement of the spleen).

Normal reference ranges:

• Babesia microti, IgG <1:64
• Babesia microti, IgM <1:20

References:

https://www.cdc.gov/parasites/babesiosis/index.html
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC120565/