Tick-Borne Rickettsioses around the World: Emerging Diseases Challenging Old Concepts

Unité des Rickettsies, CNRS UMR 6020, IFR 48, Université de la Méditerranée, Faculté de Médecine, 13385 Marseille Cedex 5, France.
Clinical Microbiology Reviews (Impact Factor: 17.41). 11/2005; 18(4):719-56. DOI: 10.1128/CMR.18.4.719-756.2005
Source: PubMed


During most of the 20th century, the epidemiology of tick-borne rickettsioses could be summarized as the occurrence of a single pathogenic rickettsia on each continent. An element of this paradigm suggested that the many other characterized and noncharacterized rickettsiae isolated from ticks were not pathogenic to humans. In this context, it was considered that relatively few tick-borne rickettsiae caused human disease. This concept was modified extensively from 1984 through 2005 by the identification of at least 11 additional rickettsial species or subspecies that cause tick-borne rickettsioses around the world. Of these agents, seven were initially isolated from ticks, often years or decades before a definitive association with human disease was established. We present here the tick-borne rickettsioses described through 2005 and focus on the epidemiological circumstances that have played a role in the emergence of the newly recognized diseases.

16 Reads
  • Source
    • "The YhbH protein, a member of the sigma (54) modulation protein family, has been reported as the virulence factor of Bacillus cereus (Oosthuizen et al., 2002) and F. tularensis (Carlson et al., 2007). For more than 30 years, IFA techniques using whole-cell rickettsial antigens have been considered the reference standard for serologic diagnosis of spotted fever rickettsioses (Parola et al., 2005; Philip et al., 1977). These assays, despite a high level of sensitivity , are specific to SFG Rickettsia, but cannot be used to ascribe a species-specific etiology. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Rickettsia parkeri is an Amblyomma-associated, spotted fever group Rickettsia species that causes an eschar-associated, febrile illness in multiple countries throughout the Western Hemisphere. Many other rickettsial species of known or uncertain pathogenicity have been detected in Amblyomma spp. ticks in the Americas, including Rickettsia amblyommii, "Candidatus Rickettsia andeanae" and Rickettsia rickettsii. In this study, we utilized an immunoproteomic approach to compare antigenic profiles of low-passage isolates of R. parkeri and R. amblyommii with serum specimens from patients with PCR- and culture-confirmed infections with R. parkeri. Five immunoreactive proteins of R. amblyommii and nine immunoreactive proteins of R. parkeri were identified by matrix-assisted laser desorption ionization tandem time-of-flight mass spectrometry. Four of these, including the outer membrane protein (Omp) A, OmpB, translation initiation factor IF-2, and cell division protein FtsZ, were antigens common to both rickettsiae. Serum specimens from patients with R. parkeri rickettsiosis reacted specifically with cysteinyl-tRNA synthetase, DNA-directed RNA polymerase subunit alpha, putative sigma (54) modulation protein, chaperonin GroEL, and elongation factor Tu of R. parkeri which have been reported as virulence factors in other bacterial species. Unique antigens identified in this study may be useful for further development of the better serological assays for diagnosing infection caused by R. parkeri. Copyright © 2015 The Authors. Published by Elsevier GmbH.. All rights reserved.
    Ticks and Tick-borne Diseases 07/2015; DOI:10.1016/j.ttbdis.2015.07.012 · 2.72 Impact Factor
  • Source
    • "Furthermore, from current knowledge of the species, it is impossible to determine their ecoregions (Guglielmone et al. 2014). From the epidemiological point of view, R. sanguineus has a high competence as a vector of pathogens of diseases such as babesiosis and ehrlichiosis in dogs and spotted and boutonneuse fevers in man (Walker et al. 2000; Parola et al. 2005; Otranto et al. 2009; Labruna et al. 2011). Comparative studies between R. sanguineus populations from Brazil (Jaboticabal, State of São Paulo) and Argentina (Rafaela, Province of Santa Fé) showed marked biological, morphological and genetic differences between the strains. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Comparative studies between brown dog tick Rhipicephalus sanguineus populations from Brazil (Jaboticabal, São Paulo) and Argentina (Rafaela, Santa Fé) showed significant biological, morphological and genetic differences between them. This work aimed to study, in a comparative way, the acquisition of resistance in domestic dogs to R. sanguineus from Jaboticabal and Rafaela, after successive and controlled infestations. Ticks were kept in a BOD incubator under controlled conditions (27 °C, 80 % relative humidity, 12-h photoperiod). Ten dogs, Dachshund breed, males and females, 6 months old, short- or long-haired, without prior contact with ticks, were used as hosts. They were distributed into two experimental groups composed of five animals each: G1 infested with ten adult couples of R. sanguineus (Jaboticabal) per animal, and G2 infested with ten adult couples of R. sanguineus (Rafaela) per animal. Ticks' biological parameters and titration of antibodies from the dogs' sera by ELISA test were used for comparison between the strains. Results of the biological parameters showed that the dogs did not acquire immunity to either of the R. sanguineus strains after repeated infestations. The ELISA test showed low antibody titers in sera of dogs from G2, in successive infestations, and higher antibody responses post second and third infestations in G1. It also demonstrated cross-reactivity between sera of dogs infested with R. sanguineus (Jaboticabal) and antigens from R. sanguineus (Rafaela) and vice versa. We conclude that Dachshund dogs did not develop resistance against neither Jaboticabal nor Rafaela strains of R. sanguineus.
    Experimental and Applied Acarology 06/2015; 67(1). DOI:10.1007/s10493-015-9936-x · 1.62 Impact Factor
  • Source
    • "Recently, the combination of the increased incidence, decline in case fatality, occurrence of multiple spotted fevers, and an increase in winter cases has sparked several questions as to whether a diagnostic error is occurring (e.g., false positives and cross-reactive positives), or if the pathogen is becoming less virulent (Dantas-Torres 2007, Cunha 2008, Raoult and Parola 2008). Diagnostic tests for RMSF are often cross-reactive with other spotted fevers including Rickettsia massiliae Beati & Raoult (Mediterranean spotted fever), Rickettsia akari (Queensland tick typhus), and Rickettsia felis Bouyer et al. (flea-borne spotted fever; Parola et al. 2005, Eremeeva et al. 2006, Raoult and Parola 2008). Additionally, pathogenic Rickettsia parkeri Lackman et al., and the strain Candidatus Rickettsia amblyommii have raised further concerns about the true prevalence of RMSF infections in the United States (Paddock et al. 2004, Paddock 2005, Whitman et al. 2007, Apperson et al. 2008). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Rocky Mountain spotted fever (RMSF), caused by the etiological agent Rickettsia rickettsii, is the most severe and frequently reported rickettsial illness in the United States, and is commonly diagnosed throughout the southeast. With the discoveries of Rickettsia parkeri and other spotted fever group rickettsiae (SFGR) in ticks, it remains inconclusive if the cases reported as RMSF are truly caused by R. rickettsii or other SFGR. Arkansas reports one of the highest incidence rates of RMSF in the country; consequently, to identify the rickettsiae in Arkansas, 1,731 ticks, 250 white-tailed deer, and 189 canines were screened by polymerase chain reaction (PCR) for the rickettsial genes gltA, rompB, and ompA. None of the white-tailed deer were positive, while two of the canines (1.1%) and 502 (29.0%) of the ticks were PCR positive. Five different tick species were PCR positive: 244 (37%) Amblyomma americanum L., 130 (38%) Ixodes scapularis Say, 65 (39%) Amblyomma maculatum (Koch), 30 (9%) Rhipicephalus sanguineus Latreille, 7 (4%) Dermacentor variabilis Say, and 26 (44%) unidentified Amblyomma ticks. None of the sequenced products were homologous to R. rickettsii. The most common Rickettsia via rompB amplification was Rickettsia montanensis and nonpathogenic Candidatus Rickettsia amblyommii, whereas with ompA amplification the most common Rickettsia was Ca. R. amblyommii. Many tick specimens collected in northwest Arkansas were PCR positive and these were commonly A. americanum harboring Ca. R. amblyommii, a currently nonpathogenic Rickettsia. Data reported here indicate that pathogenic R. rickettsii was absent from these ticks and suggest by extension that other SFGR are likely the causative agents for Arkansas diagnosed RMSF cases. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email:
    Journal of Medical Entomology 03/2015; 52(3):500-508. DOI:10.1093/jme/tjv027 · 1.95 Impact Factor
Show more

Preview (2 Sources)

16 Reads
Available from