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Volume 20, Number 9—September 2014
Research

Feeding Period Required by Amblyomma aureolatum Ticks for Transmission of Rickettsia rickettsii to Vertebrate Hosts

Danilo G. Saraiva, Herbert S. Soares, João Fábio Soares, and Marcelo B. LabrunaComments to Author 
Author affiliations: University of São Paulo, São Paulo, Brazil (D.G. Saraiva, H.S. Soares, J.F. Soares, M.B. Labruna); Bicho do Mato Research Institute, Belo Horizonte, Brazil (D.G. Saraiva)

Main Article

Table 1

Fever, seroconversion to Rickettsia rickettsii antigens, and ear and/or scrotal lesions in guinea pigs exposed to R. rickettsii-infected Amblyomma aureolatum unfed nymphs through different feeding periods, Brazil

Guinea pig no. Tick feeding period, h* Fever† R. rickettsii antibody titers‡ Ear and/or scrotal lesions§
1 2 No <1:64 No
2 2 No <1:64 No
3 4 No <1:64 No
4 4 No <1:64 No
5 6 No <1:64 No
6 6 No <1:64 No
7 8 No <1:64 No
8 8 No <1:64 No
9 8 No <1:64 No
10 8 No <1:64 No
11 10 No <1:64 No
12 10 No <1:64 No
13 12 Yes Yes
14 12 No <1:64 No
15 12 No <1:64 No
16 12 No <1:64 No
17 14 Yes 2,048 Yes
18 14 No 256 No
19 16 Yes 512 No
20 16 Yes 512 No
21 18 Yes 8,192 Yes
22 18 Yes 256 No
23 24 Yes 4,096 Yes
24 24 Yes 8,192 Yes
25 24 Yes 4,096 Yes
26 24 Yes 512 No
27 36 Yes 16,384 Yes
28 36 Yes 8,192 Yes
29 48 Yes 4,096 Yes
30 48 Yes 8,192 Yes
31 >96h Yes 16,384 Yes
32 >96h Yes 16,384 Yes

*Number of hours that infected nymphs were allowed to feed on each guinea pig before ticks were manually removed from host.
Rrectal temperature >39.5°C during 21 d after tick infestation.
‡Anti-R. rickettsii IgG endpoint titers determined 21 d after tick infestation.
§Ear or scrotal lesions (edema, necrosis) during the febrile period within 21 d after tick infestation.
¶Guinea pig died during the febrile period, before the 21st d after tick infestation; its lung was PCR-positive for Rickettsia spp.

Main Article

Page created: August 13, 2014
Page updated: August 13, 2014
Page reviewed: August 13, 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.
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