Volume 24, Number 11—November 2018
Rickettsia rickettsii Co-feeding Transmission among Amblyomma aureolatum Ticks
||Temperature range, °C
||IFA endpoint titer at day 0†
||PCR on ticks after molting, no. infected/no. tested (% infected)
|1||No fever to 38.8||32,768||UL + IN||0/10 (0)||2/2 (100)|
|2||No fever to 38.4||32,768||UL + IN||0/10 (0)||3/3 (100)|
|3||No fever to 39.1||32,768||UL||0/30 (0)|
|UL + IN
|4||No fever to 39.2||65,536||UL||0/30 (0)|
|UL + IN||5/30 (17)||3/3 (100)|
*Each guinea pig was infested on day 0 with R. rickettsii IN and on day 3 with UL. Recovered engorged larvae and nymphs were allowed to molt to nymphs and adult ticks, respectively, which were tested by real-time PCR for presence of rickettsial DNA. dpi, days postinfestation; IFA, immunofluorescence assay; IN, infected nymphs; UL, uninfected larvae.
†Blood was collected at day 0 (30 days after acquisition infestation 1) and tested by IFA with R. rickettsii antigens.
‡Tick infestations were performed on 2 feeding chambers glued to the shaved back of each guinea pig, 1 chamber receiving IN and UL, the other receiving only UL (Figure).