As Lone Star Tick-Related Illnesses Spread, ARUP Consult Offers Testing Resources To Aid Diagnosis

Tick season now comes with a growing threat: the lone star tick, which can carry disease-causing pathogens or trigger a potentially life-threatening allergy to red meat.

The lone star tick has long been found within the Southeastern United States. However, Consumer Reports reviewed several recent studies and found that populations of this tick are “exploding” in the Midwest and Northeast. Additionally, the CDC has recorded annual increases in the number of people diagnosed with the red meat allergy associated with the lone star tick.

“The expansion of the lone star tick in the U.S. has been amazing. It's geographically expanding to areas where it was not previously found,” said Marc Couturier, PhD, ARUP medical director for Emerging Public Health Crises, Parasitology/Fecal Testing, and Infectious Disease Antigen Testing. “It's unclear whether that's due to permissive temperatures, habitat destruction, or just natural ecological change, but it's been pretty dramatic.”

Peak tick season runs from May through August, with several tick species becoming active throughout their endemic regions. The lone star tick is not the only tick that’s expanding its geographic footprint, said Couturier. The typical regional patterns of multiple tick species are beginning to grow and overlap.

“The tickborne disease challenge is not going away,” he said. “If anything, it's getting more complicated.”

Couturier, who is also the head of Clinical Operations for Clinical Microbiology and Immunology, described the lone star tick as “a very aggressive feeder, unlike the other ticks that we encounter in the United States.” The lone star tick moves from host to host quickly, whereas most tick species exhibit long digestive periods after feeding.

Diagnosing Tickborne Illnesses

When it comes to tickborne illnesses, laboratory testing is crucial for determining the appropriate treatment.

“For several tickborne diseases, there are very effective treatments that can provide a resolution of symptoms after the first or second dose,” Couturier said. “Having a clearly defined answer allows you to appropriately treat the target—if it's something appropriate to treat.”

However, several tickborne illnesses can cause similar symptoms, such as fever, headache, and fatigue. “A lot of these infections start with flu-like illness,” said Couturier. “If a patient brings the physician a lone star tick that they removed from their body and they've got symptoms, the physician is going to be challenged with figuring out what's unique about the symptoms and what to consider testing or treating for.”

Laboratory testing methods for tickborne diseases include serology and nucleic acid amplification testing (NAAT). Clinicians should be aware of the tickborne illnesses that are prevalent in their practice areas, as well as the risk factors and clinical presentations associated with those illnesses. ARUP Consult^®, a free source of expert guidance on laboratory testing, offers guidance and testing algorithms to help clinicians determine the right testing approach for tickborne illnesses.

Diseases Related to the Lone Star Tick

“The tricky thing with the lone star tick is that it's a very competent vector for a lot of different infections and clinical syndromes,” Couturier said.

Named for the white splotch on the back of females, the lone star tick does not cause Lyme disease—the most common tickborne illness—but it can transmit bacteria and viruses that cause diseases such as ehrlichiosis, tularemia, heartland virus infection, and Bourbon virus infection.

In addition to bacterial or viral infections, a lone star tick bite can also cause noninfectious syndromes such as Southern tick-associated rash illness (STARI) and alpha-gal syndrome.

STARI is characterized by a rash at the site of the tick bite, as well as fever, headache, fatigue, and muscle and joint pain. The etiology of STARI is unknown.

Alpha-gal syndrome, a serious allergy to meat from mammals, is named for galactose-α-1,3-galactose, a molecule that’s found in most mammals. Symptoms of alpha-gal syndrome manifest after people eat red meat or products made from mammals, including gelatin and dairy products.

“The alpha-gal sugar can be found in things that are not conventionally identified as red meat,” Couturier said. “Gelatin can be contaminated with alpha-gal, and you can eat something that you don’t expect to contain gelatin, but it’s there as a solidifying agent. So, you could have an anaphylactic response, even if you're cognizant of your red meat allergy, simply because an unexpected food contained alpha-gal.”

Alpha-gal syndrome can be difficult to recognize and diagnose because the allergic reaction can take two to six hours to appear after ingesting meat or meat-derived products. This delay makes it hard to link the appearance of the symptoms with their cause.

Another complication with diagnosing alpha-gal syndrome is that many clinicians are unfamiliar with the condition. “This is such a recently described illness that they wouldn’t have learned about it in medical school,” Couturier said.

A CDC survey of physicians found that 42% were unaware of alpha-gal syndrome. Among those who are aware, knowledge about how to diagnose the syndrome was low.

If alpha-gal syndrome is suspected, immunoassay testing can determine if alpha-gal antibodies are present in the patient’s blood.

Tickborne Illness Resources

ARUP offers multiple resources to help provide clinicians with the latest information. The Tickborne Infections page contains information on understanding tickborne disease and answers frequently asked questions. The ARUP Consult Tickborne Diseases topic provides detailed information about test selection and interpretation.

ARUP Consult is an online laboratory test selection tool that provides point-of-care diagnostic and interpretive information for clinicians. A free educational resource, it is funded entirely by ARUP Laboratories. ARUP medical directors, who are active faculty members at the Spencer Fox Eccles School of Medicine at the University of Utah and its Department of Pathology, review and contribute to the content on ARUP Consult.

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Heather Stewart, heather.stewart@aruplab.com