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Table I.

The prevalence of infected ticks in nature and the study of vertical and transovarian transmission of SFG Rickettsiae (transovarial transmission rate (TOT): proportion of infected females giving rise to at least one positive egg or larva).

Rickettsia Tick species Infection rate (%) TOT (%)
R. conorii Rh. sanguineus 0–1.4 100*
R. rickettsii D. andersoni 0.26–1.5 100*
D. variabilis 0.0143–1.3 30–40
R. africae A. hebraeum 20–30 100
A. variegatum 27–100 Yes
R. massiliae Rh. turanicus 0.7–50 100
R. slovaca D. marginatus 7.2–40.6 100
R. rhipicephali Dermacentor sp. 1.26–1.32 38–100
R. sibirica D. nuttalli 12 100
R. bellii Amblyomma sp. 1.4–17.4 NS
I. loricatus 60.9 100
Dermacentor sp. 1.3–2.2 NS
R. helvetica I. ricinus 0.6–46.45 100
R. peacockii D. andersoni 66 73.3
R. monacensis I. ricinus 2.4–52.9 NS
R. aeschlimannii H. marginatum marginatum 1.8–57.9 Yes
R. amblyommii Amblyomma sp. 3.7–23.6 Yes
R. raoultii D. reticulatus 5.6–23 NS
D. marginatus 22.5–83.3 86.4–100

NS: Not studied.


TOT in naturally infected ticks, but no or low transmission in laboratory-infected ticks. TOT for R. conorii was studied only for the fifth generation. The duration of the infection in the ticks is unknown.