''Ornithodoros hermsi'' is a species of soft

tick Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by ...

. It can be infected with ''

Borrelia hermsii ''Borrelia hermsii'' is a spirochete bacterium that has been implicated as a cause of tick-borne relapsing fever. It is spread by the soft-bodied tick '' Ornithodoros hermsi''. References hermsii {{spirochaetes-stub ...

''.

Description

''Ornithodoros hermsi'' is a soft-bodied

of the family Argasidae. It is one of the smallest ticks of the genus ''

Ornithodoros ''Ornithodoros'' is a genus in the soft-bodied tick family, Argasidae. Physiology The opening between the midgut and hindgut has been lost, making the ticks unable to pass digestive waste products out of their bodies. Taxonomy The Linnean name ...

''. Females are larger than the males. ''O. hermsi'' has a multihost lifecycle, and some females have been observed to live four years without any blood meals. They are parasites of rodents and other small mammals. The most favored host is the western chipmunk, ''

Eutamias ''Eutamias'' is a genus of chipmunks within the tribe Marmotini of the squirrel family. It includes a single living species, the Siberian chipmunk (''Eutamias sibiricus''). The genus is often treated as a subgenus of ''Tamias'', which is now res ...

'' spp.

Lifecycle

As do all other species of ticks, ''O. hermsi'' begin as eggs, then

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

e, then nymphs, to adult ticks. ''O. hermsi'' has two larval molts and three nymphal stages. The nymphal blood meals and the greater volume of blood intake will increase the development from nymphs to adults and decrease the number of nymphal stages.

Distribution

''O. hermsi'' is found in the northwestern region of the United States, including Washington, Oregon, California, Idaho, Colorado, and even northern Arizona and New Mexico. Additionally, the species is found in southwest

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

, Canada. The ticks are found in timbered regions and at high altitudes. Wood used for fuel and lumber are common locations, as are hollow pine logs, Douglas firs, and wooden cabins. ''O. hermsi'' has been found in the nests of birds and rodents.

Medical and veterinary importance

This species is a vector of ''

'', which can cause tick-borne relapsing fever in humans. which are spread from ''O. hermsi'' to animals to humans or directly to humans. Unlike hard-bodied ticks, Ixodidae, ''O. hermsi'' feeds on a host for a short period ranging from 15–20 minutes. They often feed at night. The bites are not painful nor noticeable, which is dangerous as victims of the bite will not know they are affected until symptoms of TBRF appear. The a higher transmission of ''B. hermsii'' in late-stage nymphs and adult ticks is because they have larger blood meals, so longer feeding times.

References

{{Authority control Arachnids of North America Ticks Argasidae Animals described in 1935