scholarly journals Minimal Duration of Tick Attachment Sufficient for Transmission of Infectious Rickettsia rickettsii (Rickettsiales: Rickettsiaceae) by Its Primary Vector Dermacentor variabilis (Acari: Ixodidae): Duration of Rickettsial Reactivation in the Vector Revisited

2019 ◽  
Author(s):  
Michael L Levin ◽  
Shelby L Ford ◽  
Kris Hartzer ◽  
Lnna Krapiunaya ◽  
Hannah Stanley ◽  
...  
Keyword(s):  
Salivary Glands ◽  
Guinea Pigs ◽  
Pathogenic Bacteria ◽  
Spotted Fever ◽  
Dermacentor Variabilis ◽  
Control Group ◽  
Spotted Fever Group ◽  
Susceptible Host ◽  
Rickettsia Rickettsii ◽  
Tick Attachment

Abstract It has been reported that starving ticks do not transmit spotted fever group Rickettsia immediately upon attachment because pathogenic bacteria exist in a dormant, uninfectious state and require time for ‘reactivation’ before transmission to a susceptible host. To clarify the length of reactivation period, we exposed guinea pigs to bites of Rickettsia rickettsii-infected Dermacentor variabilis (Say) and allowed ticks to remain attached for predetermined time periods from 0 to 48 h. Following removal of attached ticks, salivary glands were immediately tested by PCR, while guinea pigs were observed for 10–12 d post-exposure. Guinea pigs in a control group were subcutaneously inoculated with salivary glands from unfed D. variabilis from the same cohort. In a parallel experiment, skin at the location of tick bite was also excised at the time of tick removal to ascertain dissemination of pathogen from the inoculation site. Animals in every exposure group developed clinical and pathological signs of infection. The severity of rickettsial infection in animals increased with the length of tick attachment, but even attachments for less than 8 h resulted in clinically identifiable infection in some guinea pigs. Guinea pigs inoculated with salivary glands from unfed ticks also became severely ill. Results of our study indicate that R. rickettsii residing in salivary glands of unfed questing ticks does not necessarily require a period of reactivation to precede the salivary transmission and ticks can transmit infectious Rickettsia virtually as soon as they attach to the host.

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.

Spotted fever group rickettsiae in immature and adult ticks (Acari: Ixodidae) from a focus of Rocky Mountain spotted fever in Connecticut

1985 ◽  
Vol 31 (12) ◽  
pp. 1131-1135 ◽  
Author(s):  
Louis A. Magnarelli ◽  
John F. Anderson ◽  
Willy Burgdorfer ◽  
Robert N. Philip ◽  
W. Adrian Chappell
Keyword(s):  
Spotted Fever ◽  
Fluorescent Antibody ◽  
Rocky Mountain ◽  
Dermacentor Variabilis ◽  
Etiologic Agent ◽  
Ixodid Ticks ◽  
Spotted Fever Group ◽  
Rocky Mountain Spotted Fever ◽  
Serum Samples ◽  
Rickettsia Rickettsii

Immature and adult ixodid ticks were collected during 1983 and 1984 in Newtown, Connecticut, an area endemic for Rocky Mountain spotted fever (RMSF), to determine prevalence of infection by spotted fever group (SFG) rickettsiae. Direct fluorescent-antibody (FA) staining revealed SFG organisms in 6 (1.8%) of 332 Dermacentor variabilis larvae, 5 (7.8%) of 64 D. variabilis nymphs, and in 2 (40%) of 5 Ixodes cookei nymphs removed from small- and medium-sized mammals. Hemolymph tests detected rickettsia-like organisms in 15 (8.8%) of 170 D. variabilis adults; 8 specimens retested by direct FA were negative. In contrast, hemocytes from 5 (8.6%) of 58 Ixodes texanus females contained organisms that stained positively in both hemolymph and direct FA tests. An indirect microimmunofluorescence test identified specific antibodies to Rickettsia rickettsii, the etiologic agent of RMSF, in serum samples from a chipmunk, raccoons, and white-footed mice. Results indicate that immature or adult ticks of at least three species may be involved in the maintenance and transmission of SFG rickettsiae at Newtown.

scholarly journals Quantitative Analyses of Variations in the Injury of Endothelial Cells Elicited by 11 Isolates of Rickettsia rickettsii

2001 ◽  
Vol 8 (4) ◽  
pp. 788-796 ◽  
Author(s):  
Marina E. Eremeeva ◽  
Gregory A. Dasch ◽  
David J. Silverman
Keyword(s):  
North Carolina ◽  
Endothelial Cells ◽  
Reduced Glutathione ◽  
Spotted Fever ◽  
Ixodid Ticks ◽  
Spotted Fever Group ◽  
Cellular Injury ◽  
Rickettsia Rickettsii ◽  
Cytopathic Effects ◽  
Group I

ABSTRACT Eleven isolates of spotted fever group rickettsiae from the blood of patients or ixodid ticks from North and South America were characterized. All isolates were identified as Rickettsia rickettsii using restriction fragment length polymorphism analysis of a 532-bp rOmpA gene fragment obtained by PCR. The ability of the R. rickettsii isolates to elicit cytopathic effects and parameters of oxidative injury were examined in cultured human EA.hy 926 endothelial cells. Cytopathic effects were determined by direct observation of infected cultures, by measuring the release of cytoplasmic lactate dehydrogenase (LDH), and by determination of intracellular pools of peroxide and reduced glutathione. Four biotypes of R. rickettsii were defined. Group I included two highly cytopathic isolates from Montana, Bitterroot and Sheila Smith, and three isolates from Maryland, North Carolina, and Brazil. These isolates rapidly damaged cells, released large amounts of cytoplasmic LDH, caused accumulation of intracellular peroxide, and depleted intracellular pools of reduced glutathione. Group II contained three isolates, two from Montana, Hlp#2 and Lost Horse Canyon, and an isolate from Colombia, which were similar to group I but caused either lower responses in LDH release or smaller changes in intracellular peroxide levels. The group III isolates, Sawtooth from Montana and 84JG from North Carolina, caused lower cellular injury by all measures. Group IV isolate Price T from Montana was the least cytopathic and caused minimal alterations of all parameters measured. Understanding the molecular basis for the varied cellular injury caused by different isolates of R. rickettsii may contribute to improved treatment of Rocky Mountain spotted fever and to the rapid identification of those isolates which are more likely to cause fulminant disease.

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.

Confirming Rickettsia rickettsii as the etiological agent of lethal spotted fever group rickettsiosis in human patients from Espírito Santo state, Brazil

2018 ◽  
Vol 9 (3) ◽  
pp. 496-499 ◽  
Author(s):  
Álvaro A. Faccini-Martínez ◽  
Sebastián Muñoz-Leal ◽  
Igor C.L. Acosta ◽  
Stefan Vilges de Oliveira ◽  
Ana Íris de Lima Duré ◽  
...  
Keyword(s):  
Spotted Fever ◽  
Etiological Agent ◽  
Spotted Fever Group ◽  
Espírito Santo ◽  
Rickettsia Rickettsii ◽  
Espirito Santo

Detection of a Rickettsia sp. and an Ehrlichia chaffeensis-like organism in ticks parasitizing the endangered Florida Grasshopper Sparrow (Ammodramus savannarum floridanus)

2020 ◽  
Vol 25 (12) ◽  
pp. 2165-2171
Author(s):  
Erin L. Hewett Ragheb ◽  
Karl E. Miller ◽  
Katherine A. Sayler ◽  
Richard G. Robbins
Keyword(s):  
Causative Agent ◽  
Pathogenic Bacteria ◽  
Spotted Fever ◽  
The United States ◽  
Mediterranean Spotted Fever ◽  
Spotted Fever Group ◽  
Ehrlichia Chaffeensis ◽  
Grasshopper Sparrow ◽  
Ammodramus Savannarum ◽  
Human Monocytic Ehrlichiosis

Between 2013 and 2015, 163 resident endangered Florida Grasshopper Sparrows (Ammodramus savannarum floridanus) and four migratory Eastern Grasshopper Sparrows (A. savannarum pratensis) were examined for the presence of ticks in peninsular Florida. Thirteen Amblyomma maculatum and seven Haemaphysalis chordeilis ticks were removed from 13 Florida Grasshopper Sparrows. Two A. maculatum were discovered on two Eastern Grasshopper Sparrows. Polymerase chain reaction (PCR) and sequencing of resultant amplicons of some of the tick specimens were performed to determine if ticks were infected with pathogenic bacteria. Salivary gland and midgut contents of five of six (83%) of the H. chordeilis tested positive for a novel Rickettsia closely related to, but distinct from, Rickettsia aeschlimannii (causative agent of Mediterranean spotted fever-like illness), an infectious zoonotic bacterium that has not been previously reported in the United States. Four of 14 (29%) of the A. maculatum tested positive for an agent most closely related to an uncultured Ehrlichia previously isolated from Oriental house rats (Rattus tanezumi; 97.5% identity to GenBank KM817187), which is genetically similar to Ehrlichia chaffeensis (causative agent of human monocytic ehrlichiosis), another infectious zoonotic bacterium. Blood from 16 Florida Grasshopper Sparrows and one Eastern Grasshopper Sparrow tested negative for spotted fever group rickettsiae, Anaplasma spp. and Ehrlichia spp. We recommend that additional collections and screening of ticks and blood from Florida Grasshopper Sparrows be undertaken to determine the rates of infection with rickettsiae and ehrlichiae in these imperiled songbirds.

Rickettsial Diseases

2017 ◽  
Author(s):  
Lisa Sun ◽  
Michael V. Johnston
Keyword(s):  
Endothelial Cells ◽  
Q Fever ◽  
Spotted Fever ◽  
The United States ◽  
Dermacentor Variabilis ◽  
Farm Animals ◽  
Spotted Fever Group ◽  
Rocky Mountain Spotted Fever ◽  
The World ◽  
The Brain

Tick-borne rickettsioses are emerging as more important health problems throughout the world. The spotted fever group including Rickettsia rickettsia can cause encephalopathy, meningitis and brain damage by selectively targeting capillary endothelial cells in the brain, and stimulating inflammation, capillary leakage, hemorrhage, and intravascular coagulation. Rickettsia are are arthropod-borne gram-negative coccobacilli bacteria and are obligate intracellular organisms that do not survive in artificial medium. In North and South America, the most common rickettsial disorder is rocky mountain spotted fever (RMSF) transmitted by the dog tick Dermacentor variabilis or the wood tick Dermacentor andersoni. A characteristic “starry sky” pattern can be seen on MRI imaging of the brain in some patients with RMSF encephalopathy and is thought to reflect the organisms targeting of brain endothelial cells in capillaries the white matter. Early treatment with doxycycline is curative and reverses signs of encephalopathy if given within a few day of onset, but delayed treatment can be associated with permanent neurological disability. The typhus group of rickettsia bacteria include R. prowazekii, which causes epidemic typhus and R. typhi, which causes murine typhus (endemic) typhus in tropical and subtropical parts of the world. Flying squirrels and humans carry R prowazekii and rats are carry R. typhi. Q fever caused by the rickettsia organism Coxiella burnetti is transmitted from farm animals including sheep and is seen throughout the world including the United States.

scholarly journals Spotted Fever GroupRickettsiaInfection and Transmission Dynamics inAmblyomma maculatum

2019 ◽  
Vol 87 (4) ◽  
Author(s):  
Chanakan Suwanbongkot ◽  
Ingeborg M. Langohr ◽  
Emma K. Harris ◽  
Wellesley Dittmar ◽  
Rebecca C. Christofferson ◽  
...  
Keyword(s):  
Salivary Glands ◽  
Spotted Fever ◽  
Attachment Site ◽  
Spotted Fever Group ◽  
Tick Feeding ◽  
Tick Saliva ◽  
Content Type ◽  
Feeding Site ◽  
Vertebrate Hosts ◽  
Tick Salivary Glands

ABSTRACTTick vectors are capable of transmitting several rickettsial species to vertebrate hosts, resulting in various levels of disease. Studies have demonstrated the transmissibility of both rickettsial pathogens and novelRickettsiaspecies or strains with unknown pathogenicity to vertebrate hosts during tick blood meal acquisition; however, the quantitative nature of transmission remains unknown. We tested the hypothesis that if infection severity is a function of the rickettsial load delivered during tick transmission, then a more virulent spotted fever group (SFG)Rickettsiaspecies is transmitted at higher levels during tick feeding. UsingAmblyomma maculatumcohorts infected withRickettsia parkerior “CandidatusRickettsia andeanae,” a quantitative PCR (qPCR) assay was employed to quantify rickettsiae in tick salivary glands and saliva, as well as in the vertebrate hosts at the tick attachment site over the duration of tick feeding. Significantly greater numbers ofR. parkerithan of “Ca. Rickettsia andeanae” rickettsiae were present in tick saliva and salivary glands and in the vertebrate hosts at the feeding site during tick feeding. Microscopy demonstrated the presence of both rickettsial species in tick salivary glands, and immunohistochemical analysis of the attachment site identified localizedR. parkeri, but not “Ca. Rickettsia andeanae,” in the vertebrate host. Lesions were also distinct and more severe in vertebrate hosts exposed toR. parkerithan in those exposed to “Ca. Rickettsia andeanae.” The specific factors that contribute to the generation of a sustained rickettsial infection and subsequent disease have yet to be elucidated, but the results of this study suggest that the rickettsial load in ticks and during transmission may be an important element.

Comparison of an oligo-chip based assay with PCR method to measure the prevalence of tick-borne pathogenic bacteria in central Slovakia

Biologia ◽  
2008 ◽  
Vol 63 (1) ◽  
Author(s):  
Elena Kocianová ◽  
Dušan Blaškovič ◽  
Katarína Smetanová ◽  
Katarína Schwarzová ◽  
Vojtech Boldiš ◽  
...  
Keyword(s):  
Francisella Tularensis ◽  
Coxiella Burnetii ◽  
Pathogenic Bacteria ◽  
Spotted Fever ◽  
Close Correlation ◽  
Borrelia Burgdorferi Sensu Lato ◽  
Pcr Analysis ◽  
Spotted Fever Group ◽  
Specific Pcr ◽  
Wide Range

AbstractTicks are well-known vectors for a wide range of pathogenic microorganisms. We examined the presence of Rickettsia spp., Anaplasma spp., Borrelia spp., Coxiella burnetii and Francisella tularensis in Ixodes ricinus ticks collected in central Slovakia using oligo-chip based assay. Rickettsiae were detected in 5.6% of examined ticks. Borreliae and anaplasmae were identified in 2.1% and 2.8% ticks, respectively. All tested samples were negative for presence of Coxiella burnetii and Francisella tularensis. All these results were compared with those obtained by PCR analysis, and a close correlation between them was found. In addition, rickettsiae of spotted fever group (SFG), Anaplasma phagocytophilum and Borrelia burgdorferi sensu lato were found in ticks using genera or species-specific PCR methods. They are circulating in 10 out of 18 studied localities.

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