Effect of extrinsic incubation temperature on borrelial infection in various organs of Ornithodoros (O.) savignyi

Abstract

Effect of extrinsic incubation temperature on borrelial infection in various organs of Ornithodoros (O.

Effect of extrinsic incubation temperature on transstadial and transovarial transmission of Borrelia sp. in Ornithodoros (O.) savignyi and infectivity to vertebrate host.

“…The dispersal of borrelial infection in various organs of O. savignyi (Helmy et al, 2009) and ability of the tick to transmit the spirochete transovarially and transstadially (at 27 o C and 37 o C and to transmit the spirochete while feeding on uninfected hamsters at the temperatures tested in the present work prove the capacity of this tick species to serve as vector and reservoir (Hoogstraal, 1985) of Borrelia sp. in Egypt.…”

“…in various organs of female O. savignyi showed no significant difference between IRs and no. of spirochetes in each organ (including salivary glands and coxal organ) on the corresponding post infection days at 27 o C and 37 o C throughout a period of 90 days after the tick infective meal (Helmy et al, 2009). Therefore, the observed decrease of Borrelia sp.…”

“…They concluded that EI temperatures in excess of 27 o C are not permissive for transmission of B. burgdorferi to mice and pointed at disappearance of spirochetes from all nymphs at 37 o C as a possible reason of the tick failure in transmitting the spirochete to mice at this temperature. However, findings on effects of EI temperature on borrelial infection in organs of O. savignyi (Helmy et al, 2009) suggest that a decrease of IRs, no. and disappearance of spirochetes in organs of female O. savignyi might be considered as a possible reason of the decreased success of Borrelia transmission to hamsters at 17 o C but not at 37 o C as observed in the present study.…”

“…This decrease might be attributed to the general decrease of IRs and no. of spirochetes or their disappearance (Helmy et al, 2009) from the tick organs (Helmy et al, 2009) during the delayed intervals of tick post infection (60 -90 days); specially in organs responsible for transmitting infection to vertebrate host (salivary glands and coxal organ).…”

“…(mostly of relapsing fever) from 17 o C to 27 o C and 37 o C increased the mean number (no. ), infection rate (IR) and prolonged persistence of the spirochetes in different organs of the vector tick throughout 90 days after the infective blood meal (Helmy et al, 2009).…”