Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link
Volume 20, Number 3—March 2014
Letter

Rickettsia and Vector Biodiversity of Spotted Fever Focus, Atlantic Rain Forest Biome, Brazil

Cite This Article

To the Editor: Rickettsia rickettsii, R. felis, and R. parkeri, strain Atlantic rainforest, have been characterized after being found in areas to which Brazilian spotted fever (BSF) is endemic (1,2), which indicates the complexity of their epidemic and enzootic cycles. The Atlantic rain forest is one of the largest and richest biomes of Brazil, and antropic action has intensely influenced its transformation. Most BSF cases and all BSF-related deaths are recorded in this biome area.

Many BSF cases were recorded in Paraíba do Sul river basin, one of the most urbanized and industrialized areas of Brazil. To better understand arthropod and Rickettsia diversity in this area,, we analyzed 2,076 arthropods from Rio de Janeiro state, Atlantic rain forest biome.

During October 2008–November 2009, we collected ticks and fleas from hosts and environments in 7 cities where high numbers of BSF cases were recorded (Rio de Janeiro State Health Secretary, unpub. data) and where fisiogeographic characteristics differed. After morphologic classification (3), the arthropods were individually separated or grouped by sex, developmental stage, and host for total DNA extraction (4).

We used 2 Rickettsia-specific primer sets (CS2–78/CS2–323 and CS4–239/CS4–1069) to amplify 401 bp and 834 bp, respectively, of the citrate synthase gene (gltA) (5,6). Presumptive Rickettsia-positive samples were tested for spotted fever group (SFG)–specific primer set Rr190.70p/Rr190.602n for 532 bp from the ompA gene (7). R. rickettsii DNA and bi-distilled water were used as positive and negative controls, respectively. PCR products were purified (NucleoSpin Extract II kit; Macherey-Nagel, Düren, Germany), cloned (pTZ57R/T; Fermentas-Thermo Fisher Scientific, Waltham, MA, USA), and sequenced by using specific vector primer sets (BigDye Reaction kit, Applied Biosystems, Foster City, CA, USA). Sequences were edited by using SeqMan program (Lasergene 10.1; DNASTAR Inc., Madison, WI, USA), and similarities were obtained by BLAST analysis (http://blast.ncbi.nlm.nih.gov). The phylogenies were assessed by applying neighbor-joining and maximum-parsimony methods, with the Kimura 2-parameter correction model. We used ClustalW 2.1 (www.clustal.org) to align sequences and produced phylogenetic trees by using 1,000 replicates bootstrap in MEGA 5.0 software (www.megasoftware.net).

We collected and analyzed ticks of the following species: Amblyomma cajennense (1,723 ticks), Rhipicephalus sanguineus (109), Anocentor nitens (63), Boophilus microplus (33), Amblyomma aureolatum (2), and Amblyomma dubitatum (2). We collected and analyzed Ctenocephalides felis (143 fleas) and C. canis (1) fleas.

Figure

Thumbnail of Phylogenetic inferences by neighbor-joining method from 1,000 replicated trees based on partial sequence of the gltA gene (CS2 401 bp).Evolutionary distances were estimated by the Kimura 2-parameter model. Bootstrap values >60% are shown (neighbor-joining/maximum-parsimony). Sequences obtained are in boldface, and GenBank accession numbers are in parentheses, followed by the similarity percentage (BLAST, http://blast.ncbi.nlm.nih.gov), the locality acronym (PO, Porciúncula; RP, S

Figure. . . Phylogenetic inferences by neighbor-joining method from 1,000 replicated trees based on partial sequence of the Rickettsia gltA gene (CS2 401 bp). Evolutionary distances were estimated by the Kimura 2-parameter...

PCR analysis showed Rickettsia DNA in 11 individual or pooled samples. This finding indicated minimal infection rates of 0.2% (4/1,723) for A. cajennense ticks, 50% (2/4) for A. dubitatum ticks, 3.0% (1/33) for B. microplus ticks, 100% (1/1) for C. canis fleas, and 2.8% (4/143) for C. felis fleas. Expected amplicon size, determined by using the gltA 401-bp primer set, was observed for all positive samples. Two were also positive by PCR for gltA 834 bp and 4 for ompA primer set (Technical Appendix). The sequences were deposited in GenBank; BLASTn analysis (http://blast.ncbi.nlm.nih.gov/blast.cgi) indicates that these sequences belong to AG (ancestral) or SFG rickettsiae (Figure).

In phylogenetic inferences, 8 samples were grouped with SFG R. rickettsii, supported by bootstrap value >62%. In addition, 3 samples were closely related to SFG R. felis, strongly supported by bootstrap values >99%; Rickettsia sp. LIC2937Ac was closely related to AG R. bellii under a bootstrap support >99% (Figure).

Epidemic manifestations of rickettsial diseases vary by ecotope characteristics, human activity, and vector bioecology in natural foci. BSF is a clinically distinct rickettsial infection in foci to which it is endemic. BSF-related illness and death vary by the Rickettsia species that can coexist in a given area and that can share or not share epidemiologic elements.

Molecular identification of R. rickettsii in A. cajennense ticks was recorded only in the Paraíba do Sul River basin of southeastern Brazil (8), as confirmed in our study. This eco-epidemiologic aspect, its great anthropophily, and its presence in all municipalities surveyed, with absolute frequency greater than other species, demonstrates the possible effect of this tick on epidemic cycle development for the analyzed region, which does not seem to occur in other regions.

R. rickettsii infection of A. dubitatum ticks in the 1 focus analyzed might indicate its relevance in specific epidemiologic scenarios. We detected highly similar sequences of different species of Rickettsia (LIC2937A) in the same A. dubitatum tick specimen (Figure). Other studies have recorded multiple Rickettsia infections in 1 tick specimen (9,10).

Our finding of C. felis fleas in 6 of the 7 outbreaks investigated highlights the possible role of this flea in maintaining Rickettsia in Rio de Janeiro state. C. felis and C. canis fleas infected with R. rickettsii seem to confirm this potential. Nevertheless, the real epidemiologic value of this report in the BSF cycle deserves to be further investigated.

Our results indicate that dogs and horses are the primary vertebrates in the Rickettsia enzootic cycle in the investigated focus, and, considering their common presence in human environments, they must be important in maintaining possible rickettsial vectors to humans. These results contribute to the mapping of BSF-endemic areas and to the understanding of the circulation and epidemiology of Rickettsia sp. in an area with one of the highest fatal concentrations of BSF.

Top

Acknowledgments

We thank the Secretaria de Saúde do Estado do Rio de Janeiro for its help in the focus area and for notifying us about the BSF cases.

This study was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (grant nos. 2010/03554-9 and 2010/52485-0) and Conselho Nacional de Desenvolvimento Cientifico e Tecnológico, Brazil (grant no. 131700/2010-3).

Top

Nicole O. Moura-MartinianoComments to Author , Erik Machado-Ferreira, Karen M. Cardoso, Flávia S. Gehrke, Marinete Amorim, Andréa C. Fogaça, Carlos A.G. Soares, Gilberto S. Gazêta1, and Teresinha T.S. Schumaker1
Author affiliations: Universidade de São Paulo, São Paulo, Brazil (N.O. Moura-Martiniano, K.M. Cardoso, F.S. Gehrke, A.C. Fogaça, T.T.S. Schumaker); Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil (E. Machado-Ferreira, C.A.G. Soares); Fundação Oswaldo Cruz, Rio de Janeiro (M. Amorim, G.S. Gazêta)

Top

References

  1. Horta  MC, Labruna  MB, Pinter  A, Linardi  PM, Schumaker  TTS. Rickettsia infection in five areas of the state of São Paulo, Brazil. Mem Inst Oswaldo Cruz. 2007;102:793801 . DOIPubMedGoogle Scholar
  2. Silveira  I, Pacheco  RC, Szabó  MPJ, Ramos  HGC, Labruna  MB. Rickettsia parkeri in Brazil. Emerg Infect Dis. 2007;13:11113 . DOIPubMedGoogle Scholar
  3. Aragão  H, da Fonseca  F. Ixodological notes. VIII. List and key to the representatives of the Brazilian ixodological fauna [in Portuguese]. Mem Inst Oswaldo Cruz. 1961;59:11529 .PubMedGoogle Scholar
  4. Aljanabi  SM, Martinez  I. Universal and rapid salt-extraction of high quality genomic DNA for PCR- based techniques. Nucleic Acids Res. 1997;25:46923 . DOIPubMedGoogle Scholar
  5. Labruna  MB, Whitworth  T, Horta  MC, Bouyer  DH, Mcbride  JW, Camargo  LM, Rickettsia bellii and Rickettsia amblyommii in Amblyomma ticks from the State of Rondônia, Western Amazon, Brazil. J Med Entomol. 2004;41:107381. DOIPubMedGoogle Scholar
  6. Labruna  MB, Mcbride  JW, Bouyer  DH, Camargo  LMA, Camargo  EP, Walker  DH. Molecular evidence for a spotted fever group Rickettsia species in the tick Amblyomma longirostre in Brazil. J Med Entomol. 2004;41:5337. DOIPubMedGoogle Scholar
  7. Regnery  RL, Spruill  CL, Plikaytis  BD. Genotypic identification of rickettsiae and estimation of intraspecies sequence divergence for portions of two rickettsial genes. J Bacteriol. 1991;173:157689 .PubMedGoogle Scholar
  8. Guedes  E, Leite  RC, Prata  MCA, Pacheco  RC, Walker  DH, Labruna  MB. Detection of Rickettsia rickettsii in the tick Amblyomma cajennense in a new Brazilian spotted fever–endemic area in the state of Minas Gerais. Mem Inst Oswaldo Cruz. 2005;100:8415 . DOIPubMedGoogle Scholar
  9. Ferrari  FAG, Goddard  J, Paddock  CD, Varela-Stokes  A. Rickettsia parkeri and Candidatus Rickettsia andeanae in Gulf Coast ticks, Mississippi, USA. Emerg Infect Dis. 2012;18:17057. DOIPubMedGoogle Scholar
  10. Varela-Stokes  AS, Paddock  CD, Engber  B, Toliver  M. Rickettsia parkeri in Amblyomma maculatum ticks, North Carolina, USA, 2009–2010. Emerg Infect Dis. 2011;17:23503 . DOIPubMedGoogle Scholar

Top

Figure

Top

Cite This Article

DOI: 10.3201/eid2003.131013

1These authors contributed equally to this article.

Related Links

Top

Table of Contents – Volume 20, Number 3—March 2014

EID Search Options
presentation_01 Advanced Article Search – Search articles by author and/or keyword.
presentation_01 Articles by Country Search – Search articles by the topic country.
presentation_01 Article Type Search – Search articles by article type and issue.

Top

Comments

Please use the form below to submit correspondence to the authors or contact them at the following address:

Nicole O. Moura-Martiniano. Lab. de Referência Nacional em Vetores das Riquetsioses, Instituto Oswaldo Cruz–Fiocruz, Av. Brasil 4365, Pav. Lauro Travassos, anexo posterior/sala 08, Manguinhos, Rio de Janeiro, Rio de Janeiro, CEP: 21.045-900, BrasilNicole O. Moura-Martiniano. Lab. de Referência Nacional em Vetores das Riquetsioses, Instituto Oswaldo Cruz–Fiocruz, Av. Brasil 4365, Pav. Lauro Travassos, anexo posterior/sala 08, Manguinhos, Rio de Janeiro, Rio de Janeiro, CEP: 21.045-900, Brasil

Send To

10000 character(s) remaining.

Top

Page created: February 20, 2014
Page updated: February 20, 2014
Page reviewed: February 20, 2014
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.
file_external