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Distribution of Rickettsia rickettsii in ovary cells of Rhipicephalus sanguineus (Latreille1806) (Acari: Ixodidae)

Luís Flávio da Silva Costa1, Pablo Henrique Nunes1, João Fábio Soares2, Marcelo Bahia Labruna2 and Maria Izabel Camargo-Mathias1*

  • * Corresponding author: Maria I Camargo-Mathias

  • † Equal contributors

Author Affiliations

1 Departamento de Biologia, Instituto de Biociências UNESP - Rio Claro/SP, Brasil

2 Laboratório de Doenças Parasitárias do Departamento de Medicina Veterinária Preventiva e Saúde Animal - VPS, USP - São Paulo, Brasil

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Parasites & Vectors 2011, 4:222  doi:10.1186/1756-3305-4-222

Published: 25 November 2011



Considering the fact that the dog tick, Rhipicephalus sanguineus, has a great potential to become the vector of Brazilian Spotted Fever (BSF) for humans, the present study aimed to describe the distribution of the bacterium Rickettsia rickettsii, the etiological agent of BSF, in different regions of the ovaries of R. sanguineus using histological techniques. The ovaries were obtained from positive females confirmed by the hemolymph test and fed in the nymph stage on guinea pigs inoculated with R. rickettsii.


The results showed a general distribution of R. rickettsii in the ovary cells, being found in oocytes in all stages of development (I, II, III, IV and V) most commonly in the periphery of the oocyte and also in the cytoplasm of pedicel cells.


The histological analysis of the ovaries of R. sanguineus infected females confirmed the presence of the bacterium, indicating that the infection can interfere negatively in the process of reproduction of the ticks, once alterations were detected both in the shape and cell structure of the oocytes which contained bacteria.

Rickettsia rickettsii; Rhipicephalus sanguineus; Brazilian Spotted Fever; ovary; histology