Published by Utah State University Extension and Utah Plant Pest Diagnostic Laboratory
ENT-189-17
Revised July 2023
Ticks and Tick-Borne Diseases of Utah Kate Richardson, Arthropod Diagnostician • Ryan Davis, Arthropod Diagnostician • Ricardo Ramirez, Entomologist
Quick Facts • The primary tick attaching to humans and pets in Utah is the Rocky Mountain wood tick, which can transmit Colorado tick fever. • The only human-attaching tick capable of transmitting Lyme disease in Utah is the western blacklegged tick, and the likelihood of encountering one is very low. • Ticks are most frequently encountered from snowmelt through mid-July in Utah. • To protect yourself against tick-borne illnesses, always conduct a thorough tick check after being in tick habitat.
T
icks are arachnids (related to spiders and mites) that feed on the blood of animals. They are most known for their potential to transmit disease to humans and other animals. Both hard ticks (Ixodidae) and soft ticks (Aragasidae) may be encountered in Utah.
The Rocky Mountain wood tick (Dermacentor andersoni) (Fig. 1) is the most commonly encountered tick for humans and pets. The brown dog tick (Rhipicephalus sanguineus) may occasionally be brought into homes on infested dogs or animals. Less frequently encountered ticks include the winter fern tick (D. albipictus) and the western blacklegged tick (Ixodes pacificus).
Fig. 1. Rocky Mountain wood tick female adult
Fig. 2. Typical tick habitat in Utah
In Utah, ticks are usually found on grasses, low plants, and sagebrush, waiting to attach to a host (Fig. 2). Ticks do not jump or fly to find hosts. Many species of ticks occur in Utah, but most live in close association with their hosts and would never encounter humans. Ticks are of medical concern because pathogens (bacteria, viruses or protozoa) can be transmitted when infected ticks feed on humans.
LIFE CYCLE Hard ticks (Ixodidae) have four distinct life stages: egg, larva, nymph, and adult. Adult and nymphal ticks have eight legs, while newly hatched larvae have six legs and are very tiny. Visually, ticks appear to have one body segment, but two distinct segments exist, the gnathosome (mouthparts) and the idosome (body). Ticks range in size from 2 mm to 20 mm depending on the life stage and species. The number of hosts a tick will attach to depends on the tick species. Three-host ticks will attach to three different animal hosts during their life, while the one-host ticks attach to one host and remain on that host throughout their lives. Two-host ticks occur on one host as immatures and on another host in the adult stage. Ticks must take a blood meal between each life stage to molt and reproduce successfully.