Table 1: Summary of results from four key studies investigating the impact of B. burgdorferi and B. microti coinfection.

ResearchersArthritis resultsCarditis/other resultsCytokine resultsBlood analysis results

Krause et al. (1996) [18]Increased severity and duration of arthralgia and joint swelling in coinfected individualsIncreased severity and duration of splenomegaly, conjunctivitis, neck stiffness, and erythema migrans in coinfected individualsN/AHigher detection of spirochete DNA in peripheral blood in coinfected individuals

Wang et al. (2000) [22]Equal severity of arthralgia and joint swelling in individuals with evidence of previous babesial infectionEqual severity of splenomegaly, conjunctivitis, neck stiffness, and erythema migrans in individuals with evidence of babesial infectionN/AHigher Babesia seropositivity in individuals with evidence of previous babesial infection, 22% versus 7% (control)

Moro et al. (2002) [54]Increased severity of arthritis in coinfected BALB/c mice 30 days after infection versus single infection; no change in C3H/HeJ miceEqual severity of carditis in BALB/c and C3H/HeJ coinfected and singly infected miceSignificant decrease in IL-10 and IL-13 in coinfected BALB/c mice 30 days after infection; no change in C3H/HeJ mice Significant decrease in IgG in coinfected BALB/c mice 15 days after infection which returned to baseline 30 days after infection; no change in C3H/HeJ mice

Coleman et al. (2005) [55]Equal severity of arthritis in coinfected versus singly infected C3H/HeN mice or BALB/c mice Equal spleen weights in C3H/HeN or BALB/c coinfected versus singly infected mice N/AEqual parasitemia in C3H/HeN or BALB/c coinfected versus singly infected mice; elevated LDH

Symptom severity assessed by patient self-report.
Symptom severity assessed by clinical exam using criteria set forth by the American College of Rheumatology Glossary Joint Exam.