CONNECTICUT — The Centers for Disease Control and Prevention (CDC) declared 2024 a notable year for ticks after U.S. hospitals recorded the highest rates of tick bites leading to emergency department visits since 2017. Ninety percent of Lyme disease transmissions occur in the Northeast, mid-Atlantic, and upper Midwest regions of the U.S. Up to 500,000 people in the lower 48 states are projected to contract Lyme disease in 2026.

Lyme disease was identified following the appearance of mysterious symptoms in three small towns in Connecticut in 1975. The spirochetes responsible for causing Lyme disease, named Borrelia burgdorferi (Bb), were identified in a 1982 paper published in the journal Science. In the early 1980s, Lyme disease patients received treatment at Tufts-New England Medical Center in Boston. One associated symptom of the disease is erythema migrans, a skin rash.

Current countermeasures against Lyme disease involve repellents, tick checks, protective clothing, and post-exposure antibiotics. Treatments for Lyme disease include doxycycline, amoxicillin, and IV ceftriaxone. A 2017 evidence-based guideline recommended a maximum 6-week course of antibiotics for late-stage Lyme disease infections. The guideline triggered a five-year legal dispute. A judge in Texas dismissed a lawsuit against the Infectious Diseases Society of America (IDSA) regarding these guidelines. Plaintiffs alleged that a fraudulent conspiracy influenced the treatment guidelines.

Otto Yang, a physician at UCLA, reported evaluating a patient who spent $30,000 for customized testing and treatments at an out-of-state clinic. Southern California has almost no locally acquired cases of Lyme disease. "I've actually had patients cry out of happiness [after] being told they didn't have Lyme," Yang said. "That's how much fearmongering there is." He also stated, "I think I'd be happier wearing a tick-and-flea collar."

Linden Hu, a researcher based in Boston, supports clinical trials for new Lyme disease vaccines. When asked, "Do you believe in chronic Lyme disease?" Hu replied, "Yes." LYMErix, an FDA-approved Lyme disease vaccine with a 3-dose schedule, was voluntarily removed from the market in 2002 due to low uptake. Clinical trials are evaluating the safety and efficacy of oral tick-killing medications for humans containing lotilaner. A human monoclonal antibody for pre-exposure prophylaxis against Bb infection is under development, and a product involving this antibody has been licensed to a company for upcoming human studies. In May 2026, a researcher published an article in the New England Journal of Medicine advocating for oral vaccines delivered as bait to deer. Deer are the main source of blood meals for adult Ixodes ticks.

Tick-borne diseases such as anaplasmosis, babesiosis, ehrlichiosis, Rocky Mountain spotted fever, and Powassan virus are expanding in distribution. Another condition, Alpha-gal syndrome, is an allergic disorder caused by antibodies to alpha-galactose present in the saliva of Lone Star ticks. Alpha-gal syndrome can cause symptoms verging on anaphylaxis after consuming pork or beef. Lone Star ticks are present in at least 30 U.S. states.