Feeding Period Required by Amblyomma aureolatum Ticks for Transmission of Rickettsia rickettsii to Vertebrate Hosts |
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| Authors: | Danilo G. Saraiva Herbert S. Soares Jo?o Fábio Soares Marcelo B. Labruna |
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| Affiliation: | 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) |
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| Abstract: | Rocky Mountain spotted fever is endemic to the São Paulo metropolitan area, Brazil, where the etiologic agent, Rickettsia rickettsii, is transmitted to humans by adult Amblyomma aureolatum ticks. We determined the minimal feeding period required by A. aureolatum nymphs and adults to transmit R. rickettsii to guinea pigs. Unfed nymphs and unfed adult ticks had to be attached to the host for >10 hours to transmit R. rickettsii. In contrast, fed ticks needed a minimum of 10 minutes of attachment to transmit R. rickettsii to hosts. Most confirmed infections of Rocky Mountain spotted fever in humans in the São Paulo metropolitan area have been associated with contact with domestic dogs, the main host of A. aureolatum adult ticks. The typical expectation that transmission of tickborne bacteria to humans as well as to dogs requires ≥2 hours of tick attachment may discourage persons from immediately removing them and result in transmission of this lethal bacterium. |
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| Keywords: | Rickettsia rickettsii Amblyomma aureolatum Rocky Mountain spotted fever vectorborne ticks tickborne parasite bacteria Brazil |
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