Ornithodoros hermsi.

is a small, multi-host soft tick that feeds rapidly on blood in all life stages, including larva, 2 to 5 nymphal instars (primarily 3), and male and female. As adults, they can feed repeatedly and reproduce for many years. is nidicolous and primarily inhabits nest cavities and burrows of small rodents and birds, with chipmunks and tree squirrels serving as its primary hosts.

Composition and transstadial retention of the salivary glands in Ornithodoros hermsi (Acari: Argasidae).

Following several days of blood feeding by larval and nymphal ixodid (hard) ticks, the salivary glands degenerate and are completely replaced in the next life stage. Yet, what happens during the molt of immature argasid (soft) ticks after their rapid and small bloodmeal has remained a mystery. Multiple studies of nymphal Ornithodoros hermsi Wheeler (Acari: Argasidae) ticks infected with the relapsing fever spirochete Borrelia hermsii suggested the salivary glands in these ticks may not disintegrate after feeding.

sp. nov.: Relapsing Fever Spirochetes Transmitted By the Tick Designated Previously as Genomic Group II.

The taxonomic status of the relapsing fever spirochete in western North America was established in 1942 and based solely on its specific association with the soft tick vector . Multilocus sequence typing (MLST) of the , , , , and intergenic spacer of isolates collected over many years from various geographic locations and biological sources identified two distinct clades designated previously as Genomic Group I (GGI) and Genomic Group II (GGII). To better assess the taxonomic relationship of these two genomic groups to each other and other species of , DNA sequences of the entire linear chromosome were determined.

Transovarial Transmission of by Its Tick Vector and Reservoir Host .

Transovarial passage of relapsing fever spirochetes ( species) by infected female argasid ticks to their progeny is a widespread phenomenon. Yet this form of vertical inheritance has been considered rare for the North American tick infected with . A laboratory colony of was established from a single infected female and two infected males that produced a population of ticks with a high prevalence of transovarial transmission based on infection assays of single and pooled ticks feeding on mice and immunofluorescence microscopy of eggs and larvae.

Vector Specificity of the Relapsing Fever Spirochete Borrelia hermsii (Spirochaetales: Borreliaceae) for the Tick Ornithodoros hermsi (Acari: Argasidae) Involves Persistent Infection of the Salivary Glands.

The relapsing fever spirochetes Borrelia hermsii and Borrelia turicatae are each maintained and transmitted in nature by their specific tick vectors, Ornithodoros hermsi Wheeler (Acari: Argasidae) and Ornithodoros turicata (Duges), respectively. The basis for this spirochete and vector specificity is not known, but persistent colonization of spirochetes in the tick's salivary glands is presumed to be essential for transmission by these long-lived ticks that feed in only minutes on their warm-blooded hosts. To examine this hypothesis further, cohorts of O.

Establishment of a Genetically Confirmed Breeding Colony of from Wild-Caught Founders from West Africa.

are a ubiquitous and often dominant rodent across sub-Saharan Africa. Importantly, they are a natural reservoir for microbial pathogens including Lassa virus (LASV), the etiological agent of Lassa fever in humans. Lassa-infected rodents have been documented across West Africa and coincide with regions where annual outbreaks occur.

Transgenic functional complementation with a transmission -associated protein restores spirochete infectivity by tick bite.

The relapsing fever spirochete Borrelia hermsii and the Lyme disease spirochete Borrelia burgdorferi sensu stricto each produces an abundant, orthologous, outer membrane protein, Vtp and OspC, respectively, when transmitted by tick bite. Gene inactivation studies have shown that both proteins are essential for spirochete infectivity when transmitted by their respective tick vectors. Therefore, we transformed a vtp-minus mutant of B.

Host Competency of the Multimammate Rat Demonstrated by Prolonged Spirochetemias with the African Relapsing Fever Spirochete .

African multimammate rats, , are widely distributed in sub-Saharan Africa and live in close association with humans. In West Africa, numerous field studies have shown these animals may be naturally infected with the relapsing fever spirochete , the primary cause of tick-borne relapsing fever in this region of the continent. However, naturally infected individual rats have never been examined over time; therefore, the true host competency of these rats for this spirochete is unknown.

Prevalence and Strains of Colorado Tick Fever Virus in Rocky Mountain Wood Ticks in the Bitterroot Valley, Montana.

The Rocky Mountain wood tick, , has long been known to transmit human pathogens. Within the Bitterroot Valley, Ravalli County, Montana, these agents include , , and Colorado tick fever virus (CTFV). Found in the western United States where wood ticks occur, CTFV causes a biphasic, febrile illness in humans and persists in enzootic cycles involving the ticks and small mammals.

Argasid and ixodid systematics: Implications for soft tick evolution and systematics, with a new argasid species list.

The systematics of the genera and subgenera within the soft tick family Argasidae is not adequately resolved. Different classification schemes, reflecting diverse schools of scientific thought that elevated or downgraded groups to genera or subgenera, have been proposed. In the most recent classification scheme, Argas and Ornithodoros are paraphyletic and the placement of various subgenera remains uncertain because molecular data are lacking.

Conspecific hyperparasitism: An alternative route for Borrelia hermsii transmission by the tick Ornithodoros hermsi.

Ixodid and argasid ticks may hyperparasitize other individuals of their own species to acquire a blood meal, however most accounts are based on single observations and the behavior has rarely been studied. While maintaining laboratory colonies of Ornithodoros species, we noticed that unfed ticks occasionally fed on other ticks that were feeding on mice, and unfed ticks parasitized engorged ticks when confined together in tubes. Therefore, we investigated hyperparasitism by Ornithodoros hermsi and the ability of these ticks to acquire and transmit the relapsing fever spirochete Borrelia hermsii when feeding on other ticks.

Colony formation in solid medium by the relapsing fever spirochetes Borrelia hermsii and Borrelia turicatae.

Relapsing fever (RF) in North America is caused primarily by the spirochete Borrelia hermsii and is associated with the bite of its tick vector Ornithodoros hermsi. Although this spirochete was known long before the discovery of the Lyme disease (LD) spirochete, Borrelia burgdorferi, basic methods to facilitate the study of B. hermsii have lagged behind.

Ecological niche modeling and distribution of Ornithodoros hermsi associated with tick-borne relapsing fever in western North America.

Tick-borne relapsing fever in western North America is a zoonosis caused by the spirochete bacterium, Borrelia hermsii, which is transmitted by the bite of infected Ornithodoros hermsi ticks. The pathogen is maintained in natural cycles involving small rodent hosts such as chipmunks and tree squirrels, as well as the tick vector. In order for these ticks to establish sustained and viable populations, a narrow set of environmental parameters must exist, primarily moderate temperatures and moderate to high amounts of precipitation.

Borrelia lanei sp. nov. extends the diversity of Borrelia species in California.

The diversity of Borrelia species discovered in California appears to be particularly high. A divergent group of Borrelia strains collected from Ixodes ticks in California was described by Postic and co-workers and designated 'genomospecies 2' (Postic D, Garnier M, Baranton G. Int J Med Microbiol 2007;297:263-271; Postic D, Ras NM, Lane RS, Hendson M, Baranton G.

Flavivirus Infection of (Black-Legged Tick) Organotypic Cultures and Applications for Disease Control.

ticks transmit many infectious agents that cause disease, including tick-borne flaviviruses (TBFVs). TBFV infections cause thousands of human encephalitis cases worldwide annually. In the United States, human TBFV infections with Powassan virus (POWV) are increasing and have a fatality rate of 10 to 30%.

Serosurvey of Crimean-Congo Hemorrhagic Fever Virus in Cattle, Mali, West Africa.

AbstractCrimean-Congo hemorrhagic fever is a tick-borne disease caused by the arbovirus Crimean-Congo hemorrhagic fever virus (CCHFV, family Bunyaviridae, genus ). CCHFV can cause a severe hemorrhagic fever with high-case fatality rates in humans. CCHFV has a wide geographic range and has been described in around 30 countries in the Middle East, Asia, Europe, and Africa including Mali and neighboring countries.

Host associations and genomic diversity of Borrelia hermsii in an endemic focus of tick-borne relapsing fever in western North America.

Background: An unrecognized focus of tick-borne relapsing fever caused by Borrelia hermsii was identified in 2002 when five people became infected on Wild Horse Island in Flathead Lake, Montana. The terrestrial small mammal community on the island is composed primarily of pine squirrels (Tamiasciurus hudsonicus) and deer mice (Peromyscus maniculatus), neither of which was known as a natural host for the spirochete. Thus a 3-year study was performed to identify small mammals as hosts for B.

Fleas and trypanosomes of peridomestic small mammals in sub-Saharan Mali.

Background: Fleas are obligate blood-feeding ectoparasites and vectors of several bacterial zoonotic pathogens as well as trypanosomes that parasitize rodents and other small mammals. During investigations of tick- and rodent-borne diseases in Mali, West Africa, we included fleas and rodent-borne trypanosomes, both of which are poorly known in this country, but are attracting greater public health interest.

Methods: Small mammals were captured in 20 Malian villages from December 2007 to October 2011.

Laboratory Response to 2014 Ebola Virus Outbreak in Mali.

Aware of the rapid spread of Ebola virus (EBOV) during the current West African epidemic, Mali took several proactive steps to rapidly identify cases within its borders. Under the Mali International Center for Excellence in Research program, a collaboration between the National Institute of Allergy and Infectious Diseases and the Malian Ministry of Higher Education and Scientific Research established a national EBOV diagnostic site at the University of Sciences, Techniques and Technologies of Bamako in the SEREFO Laboratory. Two separate introductions of EBOV occurred in Mali from neighboring Guinea, but both chains of transmission were quickly halted, and Mali was declared "Ebola free" on 18 January 2015 and has remained so since.

Transcriptional Profiling the 150 kb Linear Megaplasmid of Borrelia turicatae Suggests a Role in Vector Colonization and Initiating Mammalian Infection.

Adaptation is key for survival as vector-borne pathogens transmit between the arthropod and vertebrate, and temperature change is an environmental signal inducing alterations in gene expression of tick-borne spirochetes. While plasmids are often associated with adaptation, complex genomes of relapsing fever spirochetes have hindered progress in understanding the mechanisms of vector colonization and transmission. We utilized recent advances in genome sequencing to generate the most complete version of the Borrelia turicatae 150 kb linear megaplasmid (lp150).

Vaccination with the variable tick protein of the relapsing fever spirochete Borrelia hermsii protects mice from infection by tick-bite.

Background: Tick-borne relapsing fevers of humans are caused by spirochetes that must adapt to both warm-blooded vertebrates and cold-blooded ticks. In western North America, most human cases of relapsing fever are caused by Borrelia hermsii, which cycles in nature between its tick vector Ornithodoros hermsi and small mammals such as tree squirrels and chipmunks. These spirochetes alter their outer surface by switching off one of the bloodstream-associated variable major proteins (Vmps) they produce in mammals, and replacing it with the variable tick protein (Vtp) following their acquisition by ticks.

SUSPECTED LYME BORRELIOSIS IN A CAPTIVE ADULT CHIMPANZEE (PAN TROGLODYTES).

An 18-yr-old female captive-born chimpanzee (Pan troglodytes) presented with an intermittent history of inappetence, lethargy, and lower limb stiffness. No notable abnormalities were found on exam or complete blood cell count and serum biochemistry analysis. Serologic testing was strongly positive via indirect fluorescent antibody testing and Western blot for Borrelia burgdorferi.

Tickborne relapsing fever, Bitterroot Valley, Montana, USA.

In July 2013, a resident of the Bitterroot Valley in western Montana, USA, contracted tickborne relapsing fever caused by an infection with the spirochete Borrelia hermsii. The patient's travel history and activities before onset of illness indicated a possible exposure on his residential property on the eastern side of the valley. An onsite investigation of the potential exposure site found the vector, Ornithodoros hermsi ticks, and 1 chipmunk infected with spirochetes, which on the basis of multilocus sequence typing were identical to the spirochete isolated from the patient.

Detection of Borrelia theileri in Rhipicephalus geigyi from Mali.

Disease burden within cattle is a concern around the world. Bovine borreliosis, one such disease, is caused by the spirochete Borrelia theileri transmitted by the bite of an infected Rhipicephalus (Boophilus) species tick. A number of species within the genus are capable of transmitting the agent and are found on multiple continents.