<i>Rickettsia parkeri</i>in Brazil

Silveira, Iara; Pacheco, Richard C.; Szabó, Matias Pablo Juán; Ramos, Hernani G. C.; Labruna, Marcelo Bahia

doi:10.3201/eid1307.061397

Cited by 136 publications

(101 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Technically, these diagnostic procedures have not allowed a precise identification of the rickettsial agent; at best, defining SFG rickettsiosis, since the three employed techniques could be efficient for any spotted fever group Rickettsia species. During the last six years, four SFG species other than R. rickettsii were reported in Brazil, two of them recognized as agents of spotted fever rickettsiosis in humans (R. parkeri and R. felis) (Raoult et al 2001, b, Horta et al 2005, Labruna et al 2007c, Silveira et al 2007). Thus, it is possible that some of the BSF cases diagnosed in the state of São Paulo could be caused by other SFG rickettsia, such as R. parkeri or R. felis.…”

Section: Discussionmentioning

confidence: 99%

“…Fleas were identified according to Linardi and Guimarães (2000) IFA was used to detect human and animal serum antibodies reactive to Rickettsia spp. Glass slides were prepared according to Horta et al (2004a), employing four Rickettsia species that are routinely maintained in our laboratory: R. rickettsii strain Taiaçu (Pinter & Labruna 2006), R. parkeri strain São Paulo (Silveira et al 2007), R. felis strain Pedreira (Horta et al 2006), and R. bellii strain Mogi (Pinter & Labruna 2006). Each Rickettsia strain was cultivated in Vero cells (or C6/36 cells in case of R. felis), and harvested when nearly 100% of the cells were infected.…”

Section: Methodsmentioning

confidence: 99%

“…R. parkeri is also the most probably rickettsial agent of the Uruguayan spotted fever, a disease that has been reported in this country since early 1990s (ContiDiaz 2003, Pacheco et al 2006. While human infection by R. parkeri is yet to be documented in Brazil, two isolates of R. parkeri have been reported infecting Amblyomma ticks in the state of São Paulo , Silveira et al 2007). In addition, serological evidence of canine infection due to R. parkeri has been reported in São Paulo and in northern Brazil (Horta et al 2004a, Labruna et al 2007a.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Rickettsia infection in five areas of the state of São Paulo, Brazil

Horta

Labruna

Pintér

et al. 2007

Mem. Inst. Oswaldo Cruz

171

121

View full text Add to dashboard Cite

This study investigated rickettsial infection in animals, humans, ticks, and fleas collected in five areas of the state of São Paulo. Eight flea species (Adoratopsylla antiquorum antiquorum, Ctenocephalides felis felis, Polygenis atopus, Polygenis rimatus, Polygenis roberti roberti, Polygenis tripus, Rhopalopsyllus lugubris, and Rhopalopsyllus lutzi lutzi), and five tick species (Amblyomma aureolatum, Amblyomma cajennense, Amblyomma dubitatum, Ixodes loricatus, and Rhipicephalus sanguineus) were collected from dogs, cats, and opossums. Rickettsia felis was the only rickettsia found infecting fleas, whereas Rickettsia bellii was the only agent infecting ticks, but no animal or human blood was shown to contain rickettsial DNA. Testing animal and human sera by indirect immunofluorescence assay against four rickettsia antigens (R. rickettsii, R. parkeri, R. felis, and R. bellii), some opossum, dog, horse, and human sera reacted to R. rickettsii with titers at least four-fold higher than to the other three rickettsial antigens. These sera were considered to have a predominant antibody response to R. rickettsii. Using the same criteria, opossum, dog, and horse sera showed predominant antibody response to R. parkeri or a very closely related genotype. Our serological results suggest that both R. rickettsii and R. parkeri infected animals and/or humans in the studied areas.Key words: Rickettsia -spotted fever -fleas -ticks -opossum -domestic animals Rickettsiae are obligate intracellular bacteria that have been classically divided into two groups: the typhus group (TG), composed of Rickettsia prowazekii and Rickettsia typhi, which are associated with lice and fleas, respectively; and the spotted fever group (SFG), which includes more than 20 valid species, mostly associated with ticks (e.g., Rickettsia rickettsii, Rickettsia parkeri), and at least one species associated with fleas (Rickettsia felis). Other species, such as Rickettsia bellii and Rickettsia canadensis, both associated with ticks, have been considered a distinct group sharing antigenic, genetic and ecological characters with both TG and SFG rickettsiae (Parola et al. 2005b). Since all SFG Rickettsia share common outer membrane antigens, conventional serological assays employing a single Rickettsia antigen (e.g., R. rickettsii) allow detecting a SFG infection, but they do not identify the Rickettsia species responsible for the infection, even in the presence of high titers (La Scola & Raoult 1997). For a more specific serological diagnosis, it is recommended techniques such as testing serum against all known Rickettsia species present in a given area, or serum cross-absorption tests (La Scola & Raoult 1997, Parola et al. 2005b).For many years, SFG rickettsiosis in the Americas was thought to be caused only by R. rickettsii, transmitted by ticks (Weiss & Moulder 1984). This rickettsia has been reported in several countries from North, Central, and South America causing an acute, highly lethal febrile disease receiving different names according to the country...

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Rickettsia infection in five areas of the state of São Paulo, Brazil

Horta

Labruna

Pintér

et al. 2007

Mem. Inst. Oswaldo Cruz

171

121

View full text Add to dashboard Cite

show abstract

“…Spotted fever caused by R. parkeri seems to have milder clinical manifestations than the classical BSF, with no fatal cases yet reported (5,6). In Brazil, human cases due to R. parkeri have not been reported; however the infection by R. parkeri and a closerelated genotype (strain COOPERI) have been reported in the ticks A. triste and Amblyomma dubitatum (=Amblyomma cooperi), respectively, in the state of São Paulo (7,8). In addition, serological evidence of R. parkeri infection has been reported in dogs, horses, and opossums in the state of São Paulo (9, Horta MC, Labruna MB, Pinter A, Linardi PM, Schumaker TT.…”

mentioning

confidence: 99%

Infección por rickettsia en capibaras (Hydrochoerus hydrochaeris) de São Paulo, Brasil: evidencia serológica de infección por Rickettsia bellii y Rickettsia parkeri

et al. 2007

Self Cite

View full text Add to dashboard Cite

Introduction. In Brazil, capybaras (Hydrochoerus hydrochaeris) are important hosts for Amblyomma ticks, which in turn can transmit rickettsiae to humans and animals. Therefore, capybaras are potential sentinels for rickettsial infection.Objective. The present study evaluated rickettsial infection in capybaras in different areas of the state of São Paulo, where rickettsiosis has never been reported. Materials and methods. Blood sera from 73 capybaras from six localities in São Paulo were tested by indirect immunofluorescence assay using Rickettsia rickettsii, Rickettsia parkeri, and Rickettsia bellii antigens. Capybara spleens were tested by PCR, targeting a fragment of the rickettsial gltA gene. Ticks were collected from each capybara sample and taxonomically identified to species. Results. A total of 94 positively reacting capybara samples, 19 (26.0%), 25 (34.2%), and 50 (68.5%) capybara sera reacted to R. rickettsii, R. parkeri, and R. bellii, respectively. Twenty-five capybara sera showed titers to R. bellii at least four-fold higher than to any of the other two antigens. These sera were considered homologous to R. bellii. Using the same criteria, 3 capybara sera were considered homologous to R. parkeri. No sera were be considered homologous to R. rickettsii. No rickettsial DNA was detected in capybara spleen samples. Ticks collected on capybaras were Amblyomma dubitatum and Amblyomma cajennense. Conclusions. The first evidence is reported of R. bellii natural infection in vertebrate hosts, and the first evidence of R. parkeri infection in capybaras. While R. parkeri is known to infect and cause disease in humans, no similar evidence for human infection has been indicated by R. bellii.

show abstract

“…In addition, it is likely that a significant number of previously reported cases of Rocky Mountain spotted fever, presumably caused by Rickettsia rickettsii, were in fact caused by R. parkeri 13,14 . Besides the United States, R. parkeri has been reported in Amblyomma triste ticks from Argentina, Brazil, and Uruguay 9,15,16 . In this last country, a number of cases of rickettsiosis, often referred as cutaneous-ganglionar rickettsiosis, have been reported since 1990, characterized by a small papulo-nodular lesion at the tick attachment site, an influenza-like illness (fever, headache, malaise), and regional lymphadenopathy in all observed cases; some cases also presented generalized rash.…”

Section: Introductionmentioning

confidence: 99%

Serological evidence of Rickettsia parkeri as the etiological agent of rickettsiosis in Uruguay

Conti‐Díaz¹,

Moraes‐Filho

Pacheco

et al. 2009

Rev. Inst. Med. trop. S. Paulo

Self Cite

View full text Add to dashboard Cite

SUMMARYWe report three new rickettsiosis human cases in Uruguay. The three clinical cases presented clinical manifestations similar to previous reported cases of Rickettsia parkeri in the United States; that is mild fever (< 40 o C), malaise, headache, rash, inoculation eschar at the tick bite site, regional lymphadenopathy, and no lethality. Serological antibody-absorption tests with purified antigens of R. parkeri and Rickettsia rickettsii, associated with immunofluorescence assay indicated that the patients in two cases were infected by R. parkeri. Epidemiological and clinical evidences, coupled with our serological analysis, suggest that R. parkeri is the etiological agent of human cases of spotted fever in Uruguay, a disease that has been recognized in that country as cutaneous-ganglionar rickettsiosis.

show abstract

Rickettsia parkeriin Brazil

Cited by 136 publications

References 13 publications

Rickettsia infection in five areas of the state of São Paulo, Brazil

Rickettsia infection in five areas of the state of São Paulo, Brazil

Infección por rickettsia en capibaras (Hydrochoerus hydrochaeris) de São Paulo, Brasil: evidencia serológica de infección por Rickettsia bellii y Rickettsia parkeri

Serological evidence of Rickettsia parkeri as the etiological agent of rickettsiosis in Uruguay

Contact Info

Product

Resources

About