Spotted fever group, typhus group rickettsioses and sennetsu neorickettsiosis in rural Thailand

Abstract Lyme and other tick-borne diseases are increasing in the eastern United States and there is a lack of research on integrated strategies to control tick vectors. Here we present results of a study on tick-borne pathogens detected from tick vectors and rodent reservoirs from an ongoing 5-yr tick suppression study in the Lyme disease-endemic state of Maryland, where human-biting tick species, including Ixodes scapularis Say (Acari: Ixodidae) (the primary vector of Lyme disease spirochetes), are abundant. During the 2017 tick season, we collected 207 questing ticks and 602 ticks recovered from 327 mice (Peromyscus spp. (Rodentia: Cricetidae)), together with blood and ear tissue from the mice, at seven suburban parks in Howard County. Ticks were selectively tested for the presence of the causative agents of Lyme disease (Borrelia burgdorferi sensu lato [s.l.]), anaplasmosis (Anaplasma phagocytophilum), babesiosis (Babesia microti), ehrlichiosis (Ehrlichia ewingii, Ehrlichia chaffeensis, and ‘Panola Mountain’ Ehrlichia) and spotted fever group rickettsiosis (Rickettsia spp.). Peromyscus ear tissue and blood samples were tested for Bo. burgdorferi sensu stricto (s.s), A. phagocytophilum, Ba. microti, and Borrelia miyamotoi. We found 13.6% (15/110) of questing I. scapularis nymphs to be Bo. burgdorferi s.l. positive and 1.8% (2/110) were A. phagocytophilum positive among all sites. Borrelia burgdorferi s.s. was found in 71.1% (54/76) of I. scapularis nymphs removed from mice and 58.8% (194/330) of captured mice. Results from study on tick abundance and pathogen infection status in questing ticks, rodent reservoirs, and ticks feeding on Peromyscus spp. will aid efficacy evaluation of the integrated tick management measures being implemented.

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Isolation of spotted fever group rickettsiae from Ixodes persulcatus ticks in the central part of Hokkaido, Japan

Medical Entomology and Zoology ◽

10.7601/mez.51.55_1 ◽

2000 ◽

Vol 51 (1) ◽

pp. 55-58 ◽

Cited By ~ 2

Author(s):

Hiromi FUJITA ◽

Nobuhiro TAKADA ◽

Emiko ISOGAI ◽

Yuriko WATANABE ◽

Takuya ITO

Keyword(s):

Spotted Fever ◽

Ixodes Persulcatus ◽

Spotted Fever Group ◽

Spotted Fever Group Rickettsiae

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

Clinical and Diagnostic Laboratory Immunology ◽

10.1128/cdli.8.4.788-796.2001 ◽

2001 ◽

Vol 8 (4) ◽

pp. 788-796 ◽

Cited By ~ 41

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.

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Seroepidemiologic Study of Human Infections with Spotted Fever Group Rickettsiae in North Carolina

Journal of Clinical Microbiology ◽

10.1128/jcm.01733-14 ◽

2014 ◽

Vol 52 (11) ◽

pp. 3960-3966 ◽

Cited By ~ 25

Author(s):

M. F. Vaughn ◽

J. Delisle ◽

J. Johnson ◽

G. Daves ◽

C. Williams ◽

...

Keyword(s):

North Carolina ◽

Spotted Fever ◽

Spotted Fever Group ◽

Spotted Fever Group Rickettsiae ◽

Human Infections ◽

Seroepidemiologic Study

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Significant Growth by Rickettsia Species within Human Macrophage-Like Cells Is a Phenotype Correlated with the Ability to Cause Disease in Mammals

Pathogens ◽

10.3390/pathogens10020228 ◽

2021 ◽

Vol 10 (2) ◽

pp. 228

Author(s):

M. Nathan Kristof ◽

Paige E. Allen ◽

Lane D. Yutzy ◽

Brandon Thibodaux ◽

Christopher D. Paddock ◽

...

Keyword(s):

Endothelial Cells ◽

Spotted Fever ◽

Growth Characteristic ◽

Human Macrophage ◽

Rickettsia Conorii ◽

Spotted Fever Group ◽

Rocky Mountain Spotted Fever ◽

Phagocytic Cells ◽

Pathogenic Potential ◽

Rickettsia Species

Rickettsia are significant sources of tick-borne diseases in humans worldwide. In North America, two species in the spotted fever group of Rickettsia have been conclusively associated with disease of humans: Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, and Rickettsia parkeri, the cause of R. parkeri rickettsiosis. Previous work in our lab demonstrated non-endothelial parasitism by another pathogenic SFG Rickettsia species, Rickettsia conorii, within THP-1-derived macrophages, and we have hypothesized that this growth characteristic may be an underappreciated aspect of rickettsial pathogenesis in mammalian hosts. In this work, we demonstrated that multiple other recognized human pathogenic species of Rickettsia, including R. rickettsii, R. parkeri, Rickettsia africae, and Rickettsiaakari can grow within target endothelial cells as well as within PMA-differentiated THP-1 cells. In contrast, Rickettsia bellii, a Rickettsia species not associated with disease of humans, and R. rickettsii strain Iowa, an avirulent derivative of pathogenic R. rickettsii, could invade both cell types but proliferate only within endothelial cells. Further analysis revealed that similar to previous studies on R. conorii, other recognized pathogenic Rickettsia species could grow within the cytosol of THP-1-derived macrophages and avoided localization with two different markers of lysosomal compartments; LAMP-2 and cathepsin D. R. bellii, on the other hand, demonstrated significant co-localization with lysosomal compartments. Collectively, these findings suggest that the ability of pathogenic rickettsial species to establish a niche within macrophage-like cells could be an important factor in their ability to cause disease in mammals. These findings also suggest that analysis of growth within mammalian phagocytic cells may be useful to predict the pathogenic potential of newly isolated and identified Rickettsia species.

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