Differentiating Lyme disease from STARI

NIAID Now | August 18, 2017

It’s easy for people to overlook the importance of fast, reliable diagnostic tests in scientific research. Most often, ill patients focus on what treatment is available for them to recover. But without a timely and accurate diagnosis, physicians won’t know the most optimal treatment to provide.

Lyme disease can be particularly difficult to diagnose, especially in its early infection phase. That’s why a new NIAID-funded study, published Aug. 16 in Science Translational Medicine, is of interest. Scientists differentiated between two tick-borne diseases that have similar early symptoms—their skin lesions are indistinguishable—and often are confused by patients and physicians: Lyme disease and southern tick-associated rash illness (STARI).

The researchers used 220 patient serum samples to compare how the immune system responds metabolically to each infection. They found differences that allowed them to distinguish between early Lyme disease and STARI with up to 98 percent accuracy. Groups from Colorado State University and the Centers for Disease Control and Prevention led the project.

Because tick species that spread Lyme disease and STARI are expanding into the same geographic regions, differentiation between the two illness is becoming of greater interest. STARI is associated with bites from lone star ticks (Amblyomma americanum). Lyme disease, caused by the bacterium Borrelia burgdorferi, is transmitted via the bite of blacklegged ticks on the East (Ixodes scapularis) and West (I. pacificus) coasts.

Lyme disease and STARI are treatable with antibiotics, even though the pathogen that causes STARI remains unknown.

The researchers plan to improve their findings in an expanded study of Lyme and STARI samples, and they hope to determine whether they can apply the metabolic comparison method to other similar rash-type conditions and co-infections.


C. Molins, et al. Metabolic differentiation of early Lyme disease from southern tick–associated rash illness (STARI). Science Translational Medicine. DOI: 10.1126/scitranslmed.aal2717 (2017).

Content last reviewed on August 18, 2017