Is Lyme disease present in Utah?

Lyme Disease in Utah

Lyme disease is extremely rare in Utah and is not considered endemic to the state. 1 While one isolated case was reported in Utah in 1982 2, the overwhelming evidence indicates that Utah is not an area where Lyme disease naturally occurs.

Geographic Distribution of Lyme Disease

Lyme disease in the United States has a very specific geographic distribution:

• Endemic regions: Approximately 90% of cases occur in about 140 counties located in:

  • Northeastern and mid-Atlantic seaboard (Connecticut, Delaware, Massachusetts, Maryland, New Jersey, New York, Pennsylvania, Rhode Island)
  • Upper north-central region (Minnesota and Wisconsin) 3, 1

• Vector distribution: The disease is transmitted by specific tick species:

  • Ixodes scapularis (black-legged or deer tick) in the Eastern United States
  • Ixodes pacificus (western black-legged tick) in the Western United States 1

• Infection rates in ticks:

  • I. scapularis ticks have infection rates of ≥20% in endemic areas
  • I. pacificus ticks have much lower infection rates (0%-14%) 3, 1

Why Lyme Disease is Rare in Utah

Several factors explain the rarity of Lyme disease in Utah:

1. Tick ecology: The primary vectors of Lyme disease are not commonly found in Utah 1

2. Bacterial prevalence: Even when western ticks (I. pacificus) are present, they have lower infection rates with Borrelia burgdorferi compared to their eastern counterparts 3, 1

3. Host factors: In western regions, many I. pacificus ticks feed on lizards, whose blood is bactericidal for B. burgdorferi, reducing transmission rates 3

4. Geographic isolation: Utah is geographically separated from the established endemic regions 1, 4

Clinical Implications

If you live in or visit Utah:

• Risk assessment: Your risk of acquiring Lyme disease locally in Utah is extremely low 1

• Travel history importance: If you develop symptoms consistent with Lyme disease in Utah, clinicians should investigate recent travel to endemic areas, as most cases diagnosed in low-incidence states occur after travel to high-incidence regions 5

• Differential diagnosis: A rash similar to the erythema migrans of Lyme disease can occur in the southern United States (Southern Tick-Associated Rash Illness or STARI), but this is associated with Amblyomma americanum ticks and is not caused by B. burgdorferi infection 3, 1

Prevention Recommendations

Even though the risk is low in Utah, general tick-bite prevention is still recommended when outdoors:

• Wear light-colored clothing to spot ticks more easily
• Use insect repellents containing DEET on exposed skin
• Apply permethrin to clothing
• Perform daily tick checks after outdoor activities
• Remove attached ticks promptly with fine-tipped tweezers 3, 1

Important Caveat

While historical data shows one isolated case reported from Utah in 1982 2, this appears to be an anomaly rather than evidence of endemic transmission. The Centers for Disease Control and Prevention and the Infectious Diseases Society of America do not list Utah among states where Lyme disease is endemic 1, 4.