/Relapsing Fever

Relapsing Fever

What is relapsing fever?

Relapsing fever is an infectious disease caused by spiral-shaped bacteria (spirochetes).

Who can contract relapsing fever?

Anyone can be infected with relapsing fever. Most people become infected in rural, wooded, mountainous areas, often at summer homes or cabins.

How is relapsing fever transmitted?

In the United States, people get relapsing fever when they are bitten by an infected Ornithodoros tick.

The ticks that can transmit relapsing fever may be found on:

  • Squirrels
  • Mice
  • Chipmunks
  • Other rodents

The rodents bring the ticks into their nests, inside homes, under flooring, and between walls.

Ornithodoros is a small, soft tick, that usually gets its blood meal from rodents, but may seek out other warm-blooded animals, including humans.

Soft ticks feed quickly, usually at night, within 10 to 45 minutes. Then they drop off their host, so people usually don’t know they have been bitten.

The disease is not communicable from person to person.

What are the symptoms of relapsing fever?

Relapsing fever is characterized by a high fever that lasts for 3 to 7 days.

Fever appears suddenly along with:

  • Chills
  • Headaches
  • Muscle aches

Other possible symptoms include:

  • Nausea
  • Vomiting
  • Abdominal pain
  • Rash

The symptoms may continue for several days and then disappears. The symptoms then return days later. These relapses may recur up to 10 times.

How is relapsing fever diagnosed?

Anyone with the above symptoms should consult their health care provider. Relapsing fever is diagnosed by clinical laboratory tests, and is treated with antibiotics.

What can be done to avoid getting relapsing fever?

The best protection against relapsing fever is knowing where and how people get it and avoiding that exposure. Watch out for potential risks when visiting or camping in mountainous or wooded areas.

If you stay in a cabin:

  • Check the sleeping areas for evidence of rodents, for example:
    • Holes in the floor or walls
    • Shredded material from mattresses
    • Rodent feces on counters or in cupboards
  • Avoid sleeping on the floor or on a bed that touches the wall.
  • If the dwelling has been unoccupied, change and wash all bedding before use.

Rodent control

Because rodents spread many diseases, household rodent control is an important health measure.

Follow these steps:

  • Thoroughly check the outside walls and foundation of the building for any openings through which rodents might enter.
    • Ensure that external doors and windows close with a tight seal.
  • Keep all food and garbage in tightly sealed containers.
    • Promptly clean up any leftover or spilled food and pet food.
  • Avoid feeding squirrels, chipmunks, and other rodents around dwellings.
  • Eliminate wood piles in, near, or under the house.
    • Store firewood outside, away from walls.
    • Stack wood on pallets or raise a few inches off the ground; this will discourage rodents from using these areas as nesting sites.

Tick control

Even if a building is rodent free, direct control of ticks in an infested building is necessary for comprehensive prevention of relapsing fever.

Hungry ticks still seek out other mammals upon which to feed if rodents are unavailable. Contact a licensed professional exterminator to discuss best tick control measures for your dwelling.

Where can I get more information?

Contact your physician or the Southern Nevada Health District, Office of Epidemiology at (702) 759-1300.

Contact Information

(702) 759-1000

Updated on: August 21, 2018

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