Lyme disease, caused by the bacterium Borrelia burgdorferi, is a concern for outdoor enthusiasts across the United States, yet the risk is not uniform nationwide. This infection is transmitted through the bite of specific tick species, leading many to question the prevalence of this disease in the arid Southwest. While ticks are present throughout Arizona, they are not the same species responsible for the vast majority of Lyme disease cases in the country. Understanding the actual tick species and their associated diseases in the state is necessary for informed prevention.
Is Lyme Disease a Local Threat
Lyme disease is primarily transmitted by the Blacklegged Tick, Ixodes scapularis, in the eastern and central U.S., and the Western Blacklegged Tick, Ixodes pacificus, along the Pacific Coast. These species thrive in humid, wooded environments and are not established throughout the arid climate of Arizona. The low humidity and high temperatures across much of the state generally limit the survival of these ticks, significantly lowering the risk of local disease transmission.
The Western Blacklegged Tick has been documented in very small numbers within Arizona, primarily in the higher elevations of the Hualapai Mountains. Surveillance has not confirmed the presence of the Lyme-causing bacteria in the local tick population. The few Lyme disease cases reported in Arizona each year are overwhelmingly acquired while traveling in other states where the disease is endemic. State health officials confirm that, to date, there are no confirmed cases of Lyme disease acquired from a tick bite within Arizona’s borders.
Identifying Ticks Common to Arizona
Several tick species are common and widespread across Arizona’s diverse landscapes. The most frequently encountered species, especially in residential and urban areas, is the Brown Dog Tick, Rhipicephalus sanguineus. This tick is unique because it can complete its entire life cycle indoors, making it a persistent pest in homes and kennels, though it primarily feeds on dogs.
Another notable species is the Rocky Mountain Wood Tick, Dermacentor andersoni, found in the northern parts of the state at higher elevations and brushy areas. These ticks are relatively large and reddish-brown. Arizona is also home to various species of “soft ticks” from the Ornithodoros genus, typically dwelling in rustic cabins and rodent nests.
Tick-Borne Illnesses Prevalent in Arizona
The local health concern involves diseases transmitted by common Arizona ticks, primarily Rocky Mountain Spotted Fever (RMSF) and Tick-Borne Relapsing Fever (TBRF). RMSF is the most frequently reported tick-borne illness in the state and is transmitted by the Brown Dog Tick. Initial symptoms typically appear two to fourteen days after a bite and include a sudden onset of high fever, severe headache, and muscle aches.
A spotted rash often develops two to four days after the fever begins, though not everyone with RMSF will develop a rash. This illness can be severe if not diagnosed and treated promptly with antibiotics. Tick-Borne Relapsing Fever, caused by soft ticks that feed quickly, often at night, is associated with rodent-infested rustic cabins in mountainous areas. TBRF is characterized by recurring episodes of high fever, chills, drenching sweats, and joint pain, which can repeat over days or weeks if left untreated.
Practical Steps for Prevention and Removal
Preventing tick bites begins with taking simple precautions when spending time outdoors, especially in grassy, brushy, or wooded habitats. Wearing long pants and long-sleeved shirts helps block ticks from reaching the skin, and tucking pant cuffs into socks prevents them from crawling up legs. Applying an EPA-registered insect repellent containing ingredients like DEET or treating clothing with permethrin provides an added layer of protection.
After returning inside, a thorough tick check should be performed on clothing, gear, pets, and all parts of the body. Pay close attention to hidden areas like the groin, armpits, and hairline.
If a tick is found attached, remove it quickly using fine-tipped tweezers. Grasp the tick close to the skin’s surface and pull upward with steady, even pressure. Avoid twisting or jerking, which can cause the mouthparts to break off. After removal, clean the bite area and hands with soap and water or rubbing alcohol, and dispose of the tick in a sealed container or by flushing it.