scholarly journals Prevalence of Rickettsia Species in Canadian Populations of Dermacentor andersoni and D. variabilis

2009 ◽  
Vol 75 (6) ◽  
pp. 1786-1789 ◽  
Author(s):  
Shaun J. Dergousoff ◽  
Andrew J. A. Gajadhar ◽  
Neil B. Chilton
Keyword(s):  
Host Specificity ◽  
Tick Species ◽  
Dermacentor Variabilis ◽  
Dermacentor Andersoni ◽  
Rickettsia Species ◽  
Rickettsia Rickettsii

ABSTRACT We determined the prevalence of rickettsiae in Dermacentor adults at 15 localities in Canada. Rickettsia rickettsii was not detected in any tick, whereas Rickettsia peacockii was present in 76% of Dermacentor andersoni adults and Rickettsia montanensis in 8% of Dermacentor variabilis adults. This host specificity was maintained in localities where both tick species occurred in sympatry.

What Is Going on With the Genus Dermacentor? Hybridizations, Introgressions, Oh My!

2019 ◽  
Vol 57 (3) ◽  
pp. 653-656 ◽  
Author(s):  
Jerome Goddard ◽  
Michelle Allerdice ◽  
J Santos Portugal ◽  
Gail M Moraru ◽  
Christopher D Paddock ◽  
...  
Keyword(s):  
Genetic Material ◽  
Single Species ◽  
Dermacentor Variabilis ◽  
Species Concepts ◽  
Rickettsia Parkeri ◽  
Public Health Perspective ◽  
Dermacentor Andersoni ◽  
Rickettsia Rickettsii ◽  
Close Relationship ◽  
Specific Species

Abstract In the 1930s, R. A. Cooley noted that Dermacentor occidentalis (Acarina: Ixodidae) and Dermacentor andersoni were closely related and could hybridize. Decades later, James Oliver discovered that crosses of Dermacentor variabilis, D. andersoni, and D. occidentalis could, on occasion, produce hybrids. A recent molecular analysis (both mtDNA and nDNA) in our laboratory revealed that certain specimens of Dermacentor andersoni nested with Dermacentor parumapertus. Does this close relationship, along with the mito-nuclear discordance we have observed, mean D. andersoni and D. parumapertus are a single species? By contemporary taxonomic criteria, this seems improbable based on their distinctly different morphologies, host associations, and ecologies. This paper explores ideas related to mito-nuclear discordance, hybridization, and introgression (primarily) not only in these two species but also other members of the genus Dermacentor. Both D. andersoni and D. parumapertus can be found on the same hosts and have sympatric distributions, so introgression of genetic material by occasional cross-mating between these two species is possible. Further, the difficulty in applying specific species concepts in ticks has been recently pointed out and a unified agreement on an integrative species concepts could clearly be useful in this situation. With the discovery of D. parumapertus as a potential vector of Rickettsia parkeri and the historically recognized role of D. andersoni in transmission of Rickettsia rickettsii, understanding the specific status of each lineage of these species (and others in the genus) is extremely important from a public health perspective.

scholarly journals Molecular Detection of Spotted Fever Group Rickettsiae (Rickettsiales: Rickettsiaceae) in Dermacentor variabilis (Acari: Ixodidae) Collected Along the Platte River in South Central Nebraska

2019 ◽  
Vol 57 (2) ◽  
pp. 519-523
Author(s):  
Brandon E Luedtke ◽  
Julie J Shaffer ◽  
Estrella Monrroy ◽  
Corey W Willicott ◽  
Travis J Bourret
Keyword(s):  
Spotted Fever ◽  
Rocky Mountain ◽  
Dermacentor Variabilis ◽  
Amblyomma Americanum ◽  
Spotted Fever Group ◽  
Rocky Mountain Spotted Fever ◽  
Rickettsia Species ◽  
Platte River ◽  
Rickettsia Rickettsii ◽  
South Central

Abstract Dermacentor variabilis is the predominant tick species in Nebraska and is presumed to be the primary vector of Rickettsia rickettsii associated with cases of Rocky Mountain spotted fever (RMSF). Interestingly, RMSF cases in Nebraska have increased on a year-to-year basis, yet the prevalence of R. rickettsii in D. variabilis ticks has not been established for Nebraska. Here we sought to set a baseline for the prevalence of R. rickettsii and other spotted fever group (SFG) rickettsiae harbored by D. variabilis ticks. Over a 3-yr period, D. variabilis were collected along the Platte River in south central Nebraska. Individual tick DNA was analyzed using endpoint PCR to identify ticks carrying SFG rickettsiae. In total, 927 D. variabilis were analyzed by PCR and 38 (4.1%) ticks tested positive for SFG rickettsiae. Presumptive positives were sequenced to identify the Rickettsia species, of which 29 (76%) were R. montanensis, 5 (13%) were R. amblyommatis, 4 (11%) were R. bellii, and R. rickettsii was not detected. These data indicate that R. rickettsii is likely at a low prevalence in south central Nebraska and spillover of R. amblyommatis into D. variabilis is likely occurring due to the invasive lone star tick (Amblyomma americanum). In addition, our data suggest that R. montanensis and R. amblyommatis could be associated with the increase in SFG rickettsiae infections in Nebraska. This information will be of value to clinicians and the general public for evaluating diagnosis of disease- and risk-associated environmental exposure, respectively.

scholarly journals Association of Different Genetic Types of Francisella-Like Organisms with the Rocky Mountain Wood Tick (Dermacentor andersoni) and the American Dog Tick (Dermacentor variabilis) in Localities Near Their Northern Distributional Limits

2011 ◽  
Vol 78 (4) ◽  
pp. 965-971 ◽  
Author(s):  
Shaun J. Dergousoff ◽  
Neil B. Chilton
Keyword(s):  
Tick Species ◽  
Horizontal Transmission ◽  
Dermacentor Variabilis ◽  
Molecular Techniques ◽  
The Other ◽  
Rrna Gene ◽  
Sympatric Populations ◽  
Dermacentor Andersoni ◽  
Content Type ◽  
Distributional Limits

ABSTRACTDermacentor andersoniandDermacentor variabilisfrom allopatric and sympatric populations near their northern distributional limits were examined for the presence ofFrancisellaspecies using molecular techniques that targeted 373 bp of the 16S rRNA gene. Although there was no evidence for the presence ofFrancisella tularensisin any tick,Francisella-like endosymbionts (FLEs) were common inD. andersoniandD. variabilisadults and immatures. A significantly greater proportion of female ticks contained FLEs compared to male ticks. In addition, significantly moreD. variabilisadult individuals contained multiple FLE sequence types than didD. andersoniadults. Ten different types of FLEs were identified based on the sequence data, which has implications for diagnostic tests and epidemiological studies ofF. tularensisin tick populations in Canada. The three most prevalent types of FLEs have been detected previously inD. andersoniorD. variabilisfrom other parts of their distributional ranges, whereas the other seven FLE types have not been reported previously. A comparison of the FLEs from both allopatric and sympatric populations of these two tick species provided insight into the relative host-specificity and the modes of transmission of these tick-borne bacteria. In general, each FLE type was specific for one tick species, suggesting vertical transmission of each bacterium. However, there were a few instances of potential cross-transfer of two FLE types to the other tick species at locations whereD. andersoniandD. variabilisoccurred in sympatry, suggesting that there may be occasional horizontal transmission of some FLEs.

Experiments on Oral Secretion of the Rocky Mountain Wood Tick, Dermacentor andersoni Stiles (Acarina: Ixodidae)

1957 ◽  
Vol 89 (1) ◽  
pp. 1-5 ◽  
Author(s):  
J. D. Gregson
Keyword(s):  
British Columbia ◽  
Pacific Northwest ◽  
Rocky Mountain ◽  
Dermacentor Variabilis ◽  
Oral Secretion ◽  
Amblyomma Maculatum ◽  
Dermacentor Andersoni ◽  
The Pacific ◽  
Tick Paralysis ◽  
Rocky Mountain Wood Tick

Tick paralysis continues to be one of the most baffling and fascinating tickborne diseases in Canada. It was first reported in this country by Todd in 1912. Since then about 250 human cases, including 28 deaths, have been recorded from British Columbia. Outbreaks in cattle have affected up to 400 animals at a time, with losses in a herd as high as 65 head. Although the disease is most common in the Pacific northwest, where it is caused by the Rocky Mountain wood tick, Dermacentor andersoni Stiles, it has lately been reported as far south as Florida and has been produced by Dermacentor variabilis Say, Amblyomma maculatum Koch, and A. americanum (L.) (Gregson, 1953). The symptoms include a gradual ascending symmetrical flaccid paralysis. Apparently only man, sheep, cattle, dogs, and buffalo (one known instance) are susceptible, but even these may not necessarily be paralysed.

scholarly journals Tick Ecdysteroid Hormone, Global Microbiota/Rickettsia Signaling in the Ovary versus Carcass during Vitellogenesis in Part-Fed (Virgin) American Dog Ticks, Dermacentor variabilis

2021 ◽  
Vol 9 (6) ◽  
pp. 1242
Author(s):  
Loganathan Ponnusamy ◽  
Haley Sutton ◽  
Robert D. Mitchell ◽  
Daniel E. Sonenshine ◽  
Charles S. Apperson ◽  
...  
Keyword(s):  
Hormonal Regulation ◽  
Natural Populations ◽  
Blood Feeding ◽  
Dermacentor Variabilis ◽  
Transovarial Transmission ◽  
Rickettsia Species ◽  
Adult Females ◽  
Dog Tick ◽  
Total Bacteria

The transovarial transmission of tick-borne bacterial pathogens is an important mechanism for their maintenance in natural populations and transmission, causing disease in humans and animals. The mechanism for this transmission and the possible role of tick hormones facilitating this process have never been studied. Injections of physiological levels of the tick hormone, 20-hydroxyecdysone (20E), into part-fed (virgin) adult females of the American dog tick, Dermacentor variabilis, attached to the host caused a reduction in density of Rickettsia montanensis in the carcass and an increase in the ovaries compared to buffer-injected controls. This injection initiates yolk protein synthesis and uptake by the eggs but has no effect on blood feeding. Francisella sp. and R. montanensis were the predominant bacteria based on the proportionality in the carcass and ovary. The total bacteria load increased in the carcass and ovaries, and bacteria in the genus Pseudomonas increased in the carcass after the 20E injection. The mechanism of how the Rickettsia species respond to changes in tick hormonal regulation needs further investigation. Multiple possible mechanisms for the proliferation of R. montanensis in the ovaries are proposed.

Collaborating With Community Scientists Across Arkansas to Update Tick Distributions and Pathogen Prevalence of Spotted Fever Group Rickettsia and Ehrlichia

2021 ◽  
Author(s):  
Ashley P G Dowling ◽  
Sean G Young ◽  
Kelly Loftin
Keyword(s):  
Tick Species ◽  
Spotted Fever ◽  
Dermacentor Variabilis ◽  
Amblyomma Americanum ◽  
Spotted Fever Group ◽  
Primary Role ◽  
Prevalence Rates ◽  
Spotted Fever Group Rickettsia ◽  
Community Science ◽  
Tick Distributions

Abstract Tick-borne diseases (TBD) in humans have dramatically increased over recent years and although the bulk of cases are attributable to Lyme Disease in the Northeastern US, TBDs like spotted fever rickettsiosis and ehrlichiosis heavily impact other parts of the country, namely the mid-south. Understanding tick and pathogen distributions and prevalence traditionally requires active surveillance, which quickly becomes logistically and financially unrealistic as the geographic area of focus increases. We report on a community science effort to survey ticks across Arkansas to obtain updated data on tick distributions and prevalence of human tick-borne disease-causing pathogens in the most commonly encountered ticks. During a 20-mo period, Arkansans submitted 9,002 ticks from 71 of the 75 counties in the state. Amblyomma americanum was the most common tick species received, accounting for 76% of total tick submissions. Nearly 6,000 samples were screened for spotted fever group Rickettsia (SFGR) and Ehrlichia, resulting in general prevalence rates of 37.4 and 5.1%, respectively. In addition, 145 ticks (2.5%) were infected with both SFGR and Ehrlichia. Arkansas Department of Health reported 2,281 spotted fever and 380 ehrlichiosis cases during the same period as our tick collections. Since known SFGR vectors Dermacentor variabilis and Amblyomma maculatum were not the most common ticks submitted, nor did they have the highest prevalence rates of SFGR, it appears that other tick species play the primary role in infecting humans with SFGR. Our investigation demonstrated the utility of community science to efficiently and economically survey ticks and identify vector-borne disease risk in Arkansas.

Prevalence of Rickettsia species in Dermacentor variabilis ticks from Ontario, Canada

2016 ◽  
Vol 7 (5) ◽  
pp. 1044-1046 ◽  
Author(s):  
Heidi Wood ◽  
Liz Dillon ◽  
Samir N. Patel ◽  
Filip Ralevski
Keyword(s):  
Dermacentor Variabilis ◽  
Rickettsia Species
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