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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Experimental Infection of the Opossum Didelphis aurita by Rickettsia felis, Rickettsia bellii, and Rickettsia parkeri and Evaluation of the Transmission of the Infection to Ticks Amblyomma cajennense and Amblyomma dubitatum

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Author(s):
Horta, Mauricio C. [1] ; Sabatini, Guilherme S. [2] ; Moraes-Filho, Jonas [2] ; Ogrzewalska, Maria [2] ; Canal, Raoni B. [3] ; Pacheco, Richard C. [2] ; Martins, Thiago F. [2] ; Matushima, Eliana R. [3] ; Labruna, Marcelo B. [2]
Total Authors: 9
Affiliation:
[1] Univ Fed Vale Sao Francisco, Colegiado Med Vet, Projeto Irrigacao Senador Nilo Coelho, BR-56300990 Petrolina, PE - Brazil
[2] Univ Sao Paulo, Dept Med Vet Prevent & Saude Anim, BR-05508 Sao Paulo - Brazil
[3] Univ Sao Paulo, Dept Patol, Fac Med Vet & Zootecnia, BR-05508 Sao Paulo - Brazil
Total Affiliations: 3
Document type: Journal article
Source: VECTOR-BORNE AND ZOONOTIC DISEASES; v. 10, n. 10, p. 959-967, DEC 2010.
Web of Science Citations: 28
Abstract

This work evaluated the infection of opossums (Didelphis aurita) by Rickettsia felis, Rickettsia bellii, and Rickettsia parkeri and their role as amplifier hosts for horizontal transmission to Amblyomma cajennense and/or Amblyomma dubitatum ticks. Infection in D. aurita was induced by intraperitoneal inoculation with R. felis (n = 4 opossums), R. bellii (n = 4), and R. parkeri (n = 2). Another group of six opossums were inoculated intraperitoneally with Leibovitz-15 sterile culture medium, representing the uninfected groups (n = 2 opossums simultaneously to each infected group). Opossum blood samples collected during the study were used for DNA extraction, followed by real-time polymerase chain reaction targeting the rickettsial gene gltA, hematology, and detection of Rickettsia spp.-reactive antibodies by indirect immunofluorescence assay. Opossums were infested with uninfected A. cajennense and/or A. dubitatum for 30 days postinoculation (DPI). Flat ticks molted from ticks fed on opossums were allowed to feed on uninfected rabbits, which were tested for seroconversion by immunofluorescence assay. Samples of flat ticks were also tested by real-time polymerase chain reaction. Inoculated opossums showed no clinical abnormalities. Antibodies to Rickettsia spp. were first detected at the second to fourth DPI, with detectable titers until the 150th DPI. Rickettsemia was detected only in one opossum inoculated with R. parkeri, at the eighth DPI. Only one A. cajennense tick (2.0%) previously fed on a R. parkeri-inoculated opossum became infected. None of the rabbits infested with opossum-derived ticks seroconverted. The study demonstrated that R. felis, R. bellii, and R. parkeri were capable to produce antibody response in opossums, however, with undetectable rickettsemia for R. felis and R. bellii, and very low rickettsemia for R. parkeri. Further studies must be done with different strains of these rickettsiae, most importantly the strains that have never gone through in vitro passages. (AU)