Table 1

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. Labruna

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

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

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