The ticks in this genus have a more globular body without the sutural line found in the various species of Argas.
The body is roughened or warty in appearance with tiny protuberances, called “mammillae.”
The hypostome has well-developed teeth.
Where Found: Several species are known in the United States, including Alaska and Hawaii, of which four are known vectors of relapsing fever in the United States.
Commonly Carry: Relapsing Fever (i.e. Rocky Mountain Spotted Fever)
The relapsing fever ticks, Ornithodoros species,
are seldom seen by the average person since they are primarily “nest ticks” which can survive starvation for months or even years. Human beings are occasionally bitten by these hungry ticks and contract cases of relapsing fever in mountain cabins, in caves, or near wild animal burrows.
Diseases Commonly Carried: Relasping Fever
Markings: See gcneral characteristics of the Ornithodoros species.
Where Found: At high elevations in the West, particularly Idaho, Oregon, Washington, California, Nevada, and Colorado
Common Hosts: small mammals such as the western chipmunk (Eutamias) or tree squirrels (Tamiasciurus). Occasionally, people sleeping in mountain cabins come in contact with infected ticks and contract relapsing fever.
Diseases Commonly Carried: It’s an efficient vector of Relapsing Fever can transmit Rocky Mountain Spotted Fever.
Where Found: in nine western states
Common Hosts: Ornithodoros parkeri is a large species which attacks man and rodents.
Diseases Commonly Carried: Even after long starvation, it is an efficient vector of relapsing fever. Both O. Turicata and O. parkeri transmit the spirochete of this disease to their offspring as far as the fourth generation.
Where Found: o. Turicata is a large species found in the Southern and Western United States in caves, holes made by burrowing animals and at campsites.
Common Hosts: Rodents, snakes, terrapins and various domestic animals, as well as man.
Commonly Carried Diseases:
Where Found: occurs in southern United States.
Common Hosts: Wild and domestic cats