Brazilian spotted fever serological investigation among equids at the Guarapiranga Dam area in the city of São Paulo, Brazil


  • Jonas Moraes Filho Universidade Santo Amaro, São Paulo – SP, Brazil
  • Amanda Oliveira de Sousa Universidade de São Paulo, Faculdade de Medicina Veterinária e Zootecnia, São Paulo – SP, Brazil
  • Tania Regina Vieira de Carvalho Universidade Santo Amaro, São Paulo – SP, Brazil
  • Marcelo Bahia Labruna Universidade de São Paulo, Faculdade de Medicina Veterinária e Zootecnia, São Paulo – SP, Brazil



Rickettsia rickettsii, Rickettsia bellii, Immunofluorescence assay, Horse, Tick


The Guarapiranga Dam region, in the metropolitan area of São Paulo, has been an endemic area for Brazilian spotted fever (BSF), a tick-borne disease caused by the bacterium Rickettsia rickettsii. In this particular area, R. rickettsii is known to be transmitted to humans by Amblyomma aureolatum, a typical dog tick that is not associated with horses. In other BSF-endemic areas, R. rickettsii transmission is associated with Amblyomma sculptum, a tick species that typically infest capybaras and horses. The Guarapiranga Dam bears abundant populations of capybaras and horses; however, since nothing is known about a possible cycle of transmission of R. rickettsii by A. sculptum in this area, this study evaluated such transmission by performing a serosurvey of horses living in the Guarapiranga Dam region. A total of 206 equids living in the margins of the Guarapiranga Dam were serologically tested for antibodies reactive to five Rickettsia species, four of the spotted fever group (R. rickettsii, R. parkeri, R. amblyommatis, R. rhipicephali) and one basal group species, R. bellii. Overall, 171 (83%) equids reacted positively to at least one Rickettsia species. A total of 160 (78%), 123 (60%), 80 (39%), 72 (35%), and 71 (34%), equid sera reacted to R. bellii, R. rickettsii, R. parkeri, R. rhipicephali, and R. amblyommatis, respectively, with endpoint titers ranging from 64 to 1024 for R. bellii, and 64 to 512 for the remaining four Rickettsia species. Endpoint titers to R. bellii (median: 256) was significantly higher (P<0.05) than the endpoint titers to the other four Rickettsia species, for which the median values varied from 64 to 128. A total of 65 (32%) equid sera showed endpoint titers to R. bellii at least 4-fold higher than those to any of the other four antigens, indicating that they have been exposed to R. bellii or a very closely related species. Our results provide serological evidence that the sampled equids were not frequently exposed to R. rickettsii-infected ticks. Since horses are a highly suitable sentinel for R. rickettsii transmission by A. sculptum, we conclude that this tick species has no epidemiological role in the transmission of R. rickettsii in the BSF-endemic area of the Guarapiranga Dam in the metropolitan area of São Paulo Municipality.


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Arzua M, Silva MAN, Famadas KM, Beati L, Barros-Battesti DM. Amblyomma Aureolatum and Ixodes Auritulus (Acari: Ixodidae) on Birds in Southern Brazil, with Notes on Their Ecology. Exp Appl Acarol. 2003;31(3-4):283-96. PMid:14974693.

Chen LF, Sexton DJ. What’s new in rocky mountain spotted fever? Infect Dis Clin North Am. 2008;22(3):415-32, vii-viii. PMid:18755382.

Companhia de Saneamento Básico do Estado de São Paulo – SABESP. Dossiê – Sistema Guarapiranga. São Paulo: SABESP; 2008. Coordenadoria de Controle de Doenças – CCD. Boletim Epidemiológico Paulista – BEPA. 2014;11(129):1-37.

Fonseca F. Validade da especie e cyclo evolutivo de Amblyomma striatum KOCH, 1844 (Acarina, Ixodidae). Mem Inst Oswaldo Cruz. 1935;9:43-58.

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(8):841-5. S0074-02762005000800004. PMid:16444414.

Guglielmone AA, Estrada-Peña A, Mangold AJ, BarrosBattesti DM, Labruna MB, Martins JR, Venzal JM, Arzua M, Keirans JE. Amblyomma aureolatum (Pallas, 1772) and Amblyomma ovale Koch, 1844 (Acari: Ixodidae): hosts, distribution and 16S rDNA sequences. Vet Parasitol. 2003;113(3-4):273-88.

Horta MC, Labruna MB, Pinter A, Linardi PM, Schumaker TTS. Rickettsia Infection in Five Areas of the State of Sao Paulo, Brazil. Mem Inst Oswaldo Cruz. 2007;102(7):793- 801. PMid:18094887.

Horta MC, Labruna MB, Sangioni LA, Vianna MCB, Gennari SM, Galvão MAM, Mafra CL, Vidotto O, Schumaker TTS, Walker DH. Prevalence of antibodies to spotted fever group Rickettsiae in humans and domestic animals in a Brazilian spotted fever-endemic area in the state of São Paulo, Brazil: serologic evidence for infection by Rickettsia rickettsii and another spotted. Am J Trop Med Hyg. 2004;71(1):93-7. ajtmh.2004.71.93. PMid:15238696.

Krawczak FS, Labruna MB, Hecht JA, Paddock CD, Karpathy SE. Genotypic characterization of Rickettsia bellii reveals distinct lineages in the United States and South America. BioMed Res Int. 2018;2018:1-8. http:// PMid:29850579.

Labruna MB, Kasai N, Ferreira F, Faccini JLH, Gennari SM. Seasonal dynamics of ticks (Acari: Ixodidae) on horses in the state of São Paulo, Brazil. Vet Parasitol. 2002;105(1):65-77. 4017(01)00649-5. PMid:11879967.

Labruna MB, Ogrzewalska M, Soares JF, Martins TF, Soares HS, Moraes-Filho J, Nieri-Bastos FA, Almeida AP, Pinter A. Experimental Infection of Amblyomma aureolatum Ticks with rickettsia rickettsii. Emerg Infect Dis. 2011;17(5):829-34. eid1705.101524. PMid:21529391.

Labruna MB. Ecology of rickettsia in South America. Ann N Y Acad Sci. 2009;1166(1):156-66. http://dx.doi. org/10.1111/j.1749-6632.2009.04516.x. PMid:19538276.

McDade JE, Newhouse VF. Natural history of Rickettsia rickettsii. Ann Rev Microbiol. 1986;40:287-309. Murray GGR, Weinert LA, Rhule EL, Welch JJ. The Phylogeny of Rickettsia using different evolutionary signatures: how tree-like is bacterial evolution? Syst Biol. 2016;65(2):265-79. sysbio/syv084. PMid:26559010.

Ogrzewalska M, Saraiva DG, Moraes-Filho J, Martins TF, Costa FB, Pinter A, Labruna MB. Epidemiology of Brazilian spotted fever in the Atlantic Forest, State of São Paulo, Brazil. Parasitology. 2012;139(10):1283- 300. PMid:22716923.

Parola P, Paddock CD, Socolovschi C, Labruna MB, Mediannikov O, Kernif T, Abdad MY, Stenos J, Bitam I, Fournier PE, Raoult D. Update on tick-borne rickettsioses around the world: a geographic approach. Clin Microbiol Rev. 2013;26(4):657-702. CMR.00032-13. PMid:24092850.

Pinter A, França AC, Souza CE, Sabbo C, Nascimento EMM, Santos FCP, Katz G, Labruna BM, Holcman MM, Alves MJCP, Horta MC, Mascheretti M, Mayo RC, Angerami RN, Brasil RA, Leite RM, Aparecida SS, Souza L, Colombo S, Oliveira VLM. Febre maculosa brasileira. Suplemento Bepa. 2011;8(1):32-51.

Pinter A, Labruna MB. Isolation of Rickettsia rickettsii and Rickettsia bellii in cell culture from the tick Amblyomma aureolatum in Brazil. Ann N Y Acad Sci. 2006;1078(1):523-9. annals.1374.103. PMid:17114770.

Sangioni LA, Horta MC, Vianna MC, Gennari SM, Soares RM, Galvão MA, Schumaker TT, Ferreira F, Vidotto O, Labruna MB. Rickettsial infection in animals and Brasilian spotted fever endemicity. Emerg Infect Dis. 2005;11(2):265-70. eid1102.040656. PMid:15752445.

Soares JF, Soares HS, Barbieri AM, Labruna MB. Experimental infection of the tick Amblyomma cajennense, Cayenne tick, with Rickettsia rickettsii, the agent of Rocky Mountain spotted fever. Med Vet Entomol. 2012;26(2):139-51. 2915.2011.00982.x. PMid:22007869.

Souza CE, Pinter A, Donalisio MR. Risk factors associated with the transmissionof Brazilian spotted fever in the Piracicaba river basin, State of São Paulo, Brazil. Rev Soc Bras Med Trop. 2015;48(1):11-17.

Ueno TEH, Costa FB, Moraes-Filho J, Agostinho WC, Fernandes WR, Labruna MB. Experimental infection of horses with Rickettsia Rickettsii. Parasit Vectors. 2016;9(1):499. 1784-y. PMid:27624315.

Vianna MC, Horta MC, Sangioni LA, Cortez A, Soares RM, Mafra CL, Galvão MA, Labruna MB, Gennari SM. Rickettsial spotted fever in Capoeirão village, Itabira, Minas Gerais, Brazil. Rev Inst Med Trop São Paulo. 2008;50(5):297-301. 46652008000500009. PMid:18949349.

Vieira A, Souza C, Labruna M, Mayo R, Souza S, Camargo-Neves V. Manual de vigilância acarológica. São Paulo: Secretaria de Estado da Saúde; 2004. p. 1-63.

Weinert LA, Werren JH, Aebi A, Stone GN, Jiggins FM. Evolution and diversity of Rickettsia bacteria. BMC Biol. 2009;7(1):1-15. 7007-7-6. PMid:19187530.




How to Cite

Moraes Filho J, Sousa AO de, Carvalho TRV de, Labruna MB. Brazilian spotted fever serological investigation among equids at the Guarapiranga Dam area in the city of São Paulo, Brazil. Braz. J. Vet. Res. Anim. Sci. [Internet]. 2019 Dec. 13 [cited 2024 Apr. 14];56(4):e158601. Available from: