The role of Rhipicephalus sanguineus sensu lato saliva in the dissemination of Rickettsia conorii in C3H/HeJ mice

N. Milhano, Tais Saito, J. Bechelli, Rong Fang, M. Vilhena, R. De Sousa, David Walker

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Animal models have been developed for the study of rickettsial pathogenesis. However, to understand what occurs during the natural route of rickettsial transmission via the tick bite, the role of tick saliva should be considered in these models. To address this, we analysed the role of tick saliva in the transmission of Rickettsia conorii (Rickettsiales: Rickettsiaceae) in a murine host by intradermally (i.d.) inoculating two groups of susceptible C3H/HeJ mice with this Rickettsia, and infesting one group with nymphal Rhipicephalus sanguineus sensu lato (Ixodida: Ixodidae) ticks. Quantification of bacterial loads and mRNA levels of interleukin-1β (IL-1β), IL-10 and NF-κB was performed in C3H/HeJ lung samples by real-time quantitative polymerase chain reaction (PCR) and real-time reverse transcriptase PCR, respectively. Lung histology was examined to evaluate the pathological manifestations of infection. No statistically significant difference in bacterial load in the lungs of mice was observed between these two groups; however, a statistically significant difference was observed in levels of IL-1β and NF-κB, both of which were higher in the group inoculated with rickettsiae but not infected with ticks. Lung histology in both groups of animals revealed infiltration of inflammatory cells. Overall, this study showed that i.d. inoculation of R.conorii caused infection in the lungs of C3H/HeJ mice and tick saliva inhibited proinflammatory effects.

Original languageEnglish (US)
JournalMedical and Veterinary Entomology
DOIs
StateAccepted/In press - 2015

Fingerprint

Rickettsia conorii
Rhipicephalus sanguineus
saliva
Inbred C3H Mouse
tick
Ticks
Saliva
ticks
lungs
mice
Lung
interleukin-1
Rickettsia
Bacterial Load
histology
Interleukin-1
quantitative polymerase chain reaction
Rickettsiaceae
polymerase chain reaction
Ixodida

Keywords

  • Rickettsia conorii
  • Intradermal inoculation
  • Real-time PCR
  • Rhipicephalus sanguineus sensu lato
  • Tick saliva

ASJC Scopus subject areas

  • Insect Science
  • veterinary(all)
  • Ecology, Evolution, Behavior and Systematics
  • Parasitology

Cite this

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title = "The role of Rhipicephalus sanguineus sensu lato saliva in the dissemination of Rickettsia conorii in C3H/HeJ mice",
abstract = "Animal models have been developed for the study of rickettsial pathogenesis. However, to understand what occurs during the natural route of rickettsial transmission via the tick bite, the role of tick saliva should be considered in these models. To address this, we analysed the role of tick saliva in the transmission of Rickettsia conorii (Rickettsiales: Rickettsiaceae) in a murine host by intradermally (i.d.) inoculating two groups of susceptible C3H/HeJ mice with this Rickettsia, and infesting one group with nymphal Rhipicephalus sanguineus sensu lato (Ixodida: Ixodidae) ticks. Quantification of bacterial loads and mRNA levels of interleukin-1β (IL-1β), IL-10 and NF-κB was performed in C3H/HeJ lung samples by real-time quantitative polymerase chain reaction (PCR) and real-time reverse transcriptase PCR, respectively. Lung histology was examined to evaluate the pathological manifestations of infection. No statistically significant difference in bacterial load in the lungs of mice was observed between these two groups; however, a statistically significant difference was observed in levels of IL-1β and NF-κB, both of which were higher in the group inoculated with rickettsiae but not infected with ticks. Lung histology in both groups of animals revealed infiltration of inflammatory cells. Overall, this study showed that i.d. inoculation of R.conorii caused infection in the lungs of C3H/HeJ mice and tick saliva inhibited proinflammatory effects.",
keywords = "Rickettsia conorii, Intradermal inoculation, Real-time PCR, Rhipicephalus sanguineus sensu lato, Tick saliva",
author = "N. Milhano and Tais Saito and J. Bechelli and Rong Fang and M. Vilhena and {De Sousa}, R. and David Walker",
year = "2015",
doi = "10.1111/mve.12118",
language = "English (US)",
journal = "Medical and Veterinary Entomology",
issn = "0269-283X",
publisher = "Wiley-Blackwell",

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T1 - The role of Rhipicephalus sanguineus sensu lato saliva in the dissemination of Rickettsia conorii in C3H/HeJ mice

AU - Milhano, N.

AU - Saito, Tais

AU - Bechelli, J.

AU - Fang, Rong

AU - Vilhena, M.

AU - De Sousa, R.

AU - Walker, David

PY - 2015

Y1 - 2015

N2 - Animal models have been developed for the study of rickettsial pathogenesis. However, to understand what occurs during the natural route of rickettsial transmission via the tick bite, the role of tick saliva should be considered in these models. To address this, we analysed the role of tick saliva in the transmission of Rickettsia conorii (Rickettsiales: Rickettsiaceae) in a murine host by intradermally (i.d.) inoculating two groups of susceptible C3H/HeJ mice with this Rickettsia, and infesting one group with nymphal Rhipicephalus sanguineus sensu lato (Ixodida: Ixodidae) ticks. Quantification of bacterial loads and mRNA levels of interleukin-1β (IL-1β), IL-10 and NF-κB was performed in C3H/HeJ lung samples by real-time quantitative polymerase chain reaction (PCR) and real-time reverse transcriptase PCR, respectively. Lung histology was examined to evaluate the pathological manifestations of infection. No statistically significant difference in bacterial load in the lungs of mice was observed between these two groups; however, a statistically significant difference was observed in levels of IL-1β and NF-κB, both of which were higher in the group inoculated with rickettsiae but not infected with ticks. Lung histology in both groups of animals revealed infiltration of inflammatory cells. Overall, this study showed that i.d. inoculation of R.conorii caused infection in the lungs of C3H/HeJ mice and tick saliva inhibited proinflammatory effects.

AB - Animal models have been developed for the study of rickettsial pathogenesis. However, to understand what occurs during the natural route of rickettsial transmission via the tick bite, the role of tick saliva should be considered in these models. To address this, we analysed the role of tick saliva in the transmission of Rickettsia conorii (Rickettsiales: Rickettsiaceae) in a murine host by intradermally (i.d.) inoculating two groups of susceptible C3H/HeJ mice with this Rickettsia, and infesting one group with nymphal Rhipicephalus sanguineus sensu lato (Ixodida: Ixodidae) ticks. Quantification of bacterial loads and mRNA levels of interleukin-1β (IL-1β), IL-10 and NF-κB was performed in C3H/HeJ lung samples by real-time quantitative polymerase chain reaction (PCR) and real-time reverse transcriptase PCR, respectively. Lung histology was examined to evaluate the pathological manifestations of infection. No statistically significant difference in bacterial load in the lungs of mice was observed between these two groups; however, a statistically significant difference was observed in levels of IL-1β and NF-κB, both of which were higher in the group inoculated with rickettsiae but not infected with ticks. Lung histology in both groups of animals revealed infiltration of inflammatory cells. Overall, this study showed that i.d. inoculation of R.conorii caused infection in the lungs of C3H/HeJ mice and tick saliva inhibited proinflammatory effects.

KW - Rickettsia conorii

KW - Intradermal inoculation

KW - Real-time PCR

KW - Rhipicephalus sanguineus sensu lato

KW - Tick saliva

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U2 - 10.1111/mve.12118

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