Relapsing Fever Ticks Identification Guide
Ornithodoros turicata
Relapsing fever ticks are soft-bodied ticks that transmit tick-borne relapsing fever to humans. Unlike hard ticks, they feed rapidly at night and live in burrows, caves, and rodent nests in the southwestern United States.
Taxonomy
Relapsing Fever Ticks Coloration
Common color patterns to help identify relapsing fever ticks
Relapsing Fever Ticks
Seasonal Activity
When relapsing fever ticks are most active throughout the year
Where Relapsing Fever Ticks Are Found
Hover over states to see their names. Green regions indicate where relapsing fever ticks have been reported.
Relapsing Fever Tick Identification Guide
Physical Characteristics
Relapsing fever ticks belong to the soft tick family. They look very different from the hard ticks most people know. Their body has no hard shield like deer ticks and dog ticks have. Instead, they have a leathery, wrinkled surface with small bumps.
Adult relapsing fever ticks are 8 to 13 millimeters long. Females are a bit larger than males. Males are about 8 mm and females about 10 mm. Their body is oval and flat when they have not fed. The color is usually gray but can be tan or reddish-brown.
One key feature is where the mouthparts sit. On soft ticks, the mouthparts are on the underside of the body. You cannot see them from above. Hard ticks have mouthparts that stick out from the head and are easy to see from above. Soft ticks also lack the grooves along the back edge that many hard ticks have.
Soft Ticks vs. Hard Ticks
Knowing the difference between soft and hard ticks helps with identification. It also explains their very different habits.
Hard ticks: These include deer ticks, dog ticks, and lone star ticks. They have a hard plate on their back. They feed for days at a time and wait on plants for hosts to pass by.
Soft ticks: These include relapsing fever ticks. They have no hard plate. They feed fast, in minutes to an hour, and live in sheltered spots near their hosts.
Relapsing Fever Tick Behavior and Biology
Habitat Preferences
Relapsing fever ticks live in nests, burrows, and other sheltered spots close to their hosts. Common habitats include:
- Rodent burrows and ground squirrel colonies
- Caves and rock crevices
- Abandoned cabins and outbuildings
- Spaces under buildings and porches
- Bird nests in protected areas
This is why people usually run into these ticks when exploring caves, staying in old cabins, or disturbing rodent nests. The ticks hide in these sheltered spots. They do not climb onto plants like hard ticks do.
Feeding Behavior
Relapsing fever ticks feed at night. They come out when hosts are sleeping and finish their blood meal fast. Most feedings take 15 to 60 minutes. This is very different from hard ticks, which stay attached for several days.
This fast feeding has a big result. People bitten by these ticks often have no idea they were bitten. The tick attaches, feeds, and leaves before the person wakes up. This makes it hard to link later illness to a tick bite.
These ticks feed on many hosts including rodents, rabbits, birds, and reptiles. They will bite humans who enter their space. Each life stage needs blood meals. A single tick may feed many times over its long life.
Life Cycle
Relapsing fever ticks go through several life stages. These are egg, larva, nymph, and adult. Each stage after the egg needs at least one blood meal to move to the next stage.
These ticks can live a very long time. Adults can survive for many years without a meal. This lets them stay alive in caves, cabins, and burrows even when hosts are hard to find.
Females lay eggs in batches after each blood meal. The eggs hatch into larvae with six legs. The larvae must feed before they can grow into the next stage. Nymphs have eight legs like adults.
Geographic Distribution
United States Populations
In North America, Ornithodoros turicata lives in two separate areas. The western group lives across the dry Southwest. This includes California, Arizona, Nevada, Utah, Colorado, New Mexico, Kansas, Oklahoma, and Texas. A separate group exists in Florida.
There is a gap where the tick has not been found in Louisiana, Mississippi, and Alabama. Scientists do not know if the tick is truly absent from these states or just hard to find there.
The tick is most common in dry regions where burrowing rodents live. Cave systems in Texas and the Southwest have the most relapsing fever cases.
Not Present in the Mid-Atlantic
Relapsing fever ticks do not live in the Mid-Atlantic region. This includes Virginia, Maryland, and Washington D.C. The tick diseases common here come from hard ticks like the deer tick and lone star tick. If you live in the Mid-Atlantic, you will not see relapsing fever ticks unless you travel to the Southwest.
Health Risks and Tick-Borne Relapsing Fever
The Disease
Tick-borne relapsing fever comes from bacteria called Borrelia turicatae. The bacteria enter the blood when the tick feeds and spread quickly. The disease gets its name from the pattern of fevers that come and go.
Symptoms usually start within two weeks of a tick bite. The first bout includes high fever (often 103 to 105 degrees F), bad headache, muscle aches, joint pain, and nausea. After several days, the fever breaks and the person feels better. But the fever comes back a few days later. This cycle can repeat many times over several weeks if not treated.
Other symptoms may include vomiting, diarrhea, stomach pain, and low blood pressure. Some patients develop a rash. The disease rarely causes death but can make you very sick without treatment.
Risk Factors
Most cases of tick-borne relapsing fever in the United States occur in people who have:
- Slept in rustic cabins in endemic areas
- Explored caves in the Southwest
- Disturbed rodent nests during construction or cleaning
- Spent time in areas with ground squirrel colonies
The disease is often associated with vacation cabins in Texas and the Southwest where rodents have infested the structures. Overnight visitors may be bitten while sleeping without knowing it.
Medical Disclaimer: This information is for educational purposes only and is not medical advice. If you develop recurring fevers after visiting caves or cabins in the Southwest, see a doctor right away and mention possible tick exposure. Relapsing fever responds well to antibiotic treatment.
Treatment Methods for Relapsing Fever Ticks
Relapsing fever ticks live in sheltered spots rather than on plants. This means control methods differ from those used for hard ticks. The best approaches focus on removing tick habitats and keeping rodents out.
Rodent exclusion: These ticks live near rodents, so keeping rodents out is key. Seal gaps and cracks in foundations. Close openings around pipes. Remove food sources that attract rodents.
Habitat changes: Clear debris that could shelter rodents near buildings. Keep plants trimmed away from structures. Move woodpiles and rock piles away from living spaces.
Crack and crevice treatments: Pest control pros may treat the cracks and voids where ticks hide. Dust products work well in enclosed spaces like wall voids and under buildings.
Cabin cleanup: In areas where these ticks live, inspect and treat unused cabins before staying in them. Check sleeping areas, look for rodent signs, and seal entry points.
Prevention Tips
If you plan to visit caves or stay in rustic cabins in the Southwest, take these precautions:
- Inspect sleeping areas for signs of rodent activity before settling in
- Sleep on elevated surfaces rather than directly on floors
- Use insect repellents containing DEET on skin and permethrin on clothing
- Keep food secured to avoid attracting rodents
- Report any structures with signs of rodent infestation to management
When exploring caves in endemic areas:
- Wear long sleeves and pants tucked into boots
- Apply repellent before entering
- Shower and check for ticks after the visit
- Be aware that bites may occur without your knowledge
References and Further Reading
Other Ticks
Explore other species in the ticks family
Commonly Confused With
Relapsing Fever Ticks are often mistaken for these similar pests
Where Relapsing Fever Ticks Are Found
Hover over states to see their names. Green regions indicate where relapsing fever ticks have been reported.
Common Questions about Relapsing Fever Ticks
What is a relapsing fever tick?
+
A relapsing fever tick is a soft-bodied tick in the genus Ornithodoros that transmits tick-borne relapsing fever to humans. Unlike common hard ticks, these ticks live in burrows and caves, feed rapidly at night, and can survive for years without a blood meal.
Where are relapsing fever ticks found?
+
In the United States, relapsing fever ticks are found primarily in the Southwest, including Texas, Arizona, California, Colorado, New Mexico, Oklahoma, Kansas, Utah, and Nevada. A separate population exists in Florida. They are not found in the Mid-Atlantic or eastern states.
How do relapsing fever ticks differ from regular ticks?
+
Relapsing fever ticks are soft ticks without a hard dorsal shield. They have a leathery, wrinkled body and feed much faster than hard ticks, often completing a blood meal in under an hour. They also live in sheltered habitats rather than waiting on vegetation.
What diseases do relapsing fever ticks transmit?
+
These ticks transmit tick-borne relapsing fever caused by the spirochete bacteria Borrelia turicatae. Symptoms include recurring episodes of high fever, headache, muscle aches, and joint pain that come and go over several weeks.
How long do relapsing fever ticks feed?
+
Unlike hard ticks that feed for days, relapsing fever ticks complete their blood meal in 15 to 60 minutes. Immature ticks may feed in less than 30 minutes, though adults can sometimes attach for up to two days.
Can relapsing fever ticks survive without feeding?
+
Yes, adult relapsing fever ticks can survive for many years without a blood meal. This long survival ability, combined with their secretive habitat in burrows and caves, makes them difficult to detect and control.
What should I do if bitten by a relapsing fever tick?
+
If you experience recurring fevers after visiting caves, cabins, or areas with rodent activity in the Southwest, seek medical attention and mention possible tick exposure. Tick-borne relapsing fever responds well to antibiotic treatment when diagnosed early.
With five years of hands-on experience in the pest control industry, George Schulz is a registered technician with the Virginia Pest Management Association and a proud third-generation professional in a family business that's been protecting homes for over 57 years. He manages and trains a team of service pros while also leading internal research efforts—recently spearheading a deep-dive review of thousands of documents on pest control materials to hand-pick the most kid and pet friendly, most effective solutions tailored specifically for homes in the DC metro area.