Table 4. Rickettsia rickettsii acquisition infestation 4 with Amblyomma aureolatum ticks on 2 guinea pigs 430 days after acquisition infestation 1, Brazil* .

Guinea pig	Temperature range, °C	IFA endpoint titer†	Feeding chambers‡	PCR on ticks after molting, no. infected/no. tested (%)
				Unfed nymphs	Unfed adults
1	No fever to 38.7	4,096	UL	ND
			UL + IN	ND	2/2 (100)
2	No fever to 38.7	512	UL	2/16 (13)
			UL + IN	1/12 (8)	5/5 (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; ND, not done because very few engorged larvae were recovered from the animal; UL, uninfected larvae.
†Blood was collected at day 0 (430, 400, and 310 days after acquisition infestations 1, 2, and 3, respectively) 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).