Table 1.

Infection status and bacterial load of X. cheopis fleas. Data are combined from fleas collected during two separate experiments. All strains were CO92 (Lcr^-)

Fleas infected with	Day p.i.	Fleas Collected (n)	Infected Fleas (%)	Median (range) CFU/Flea
Y. pestis CO92 Pgm+	0	10	100	1.5 × 104 (1.2 × 102-1.6 × 105)
	3	40	97.5	2.9 × 103 (0.0-4.9 × 104)
	7	22	100	4.7 × 103 (2.5 × 101-4.1 × 104)
	14	12	83.3	9.1 × 103 (0.0-3.9 × 104)
	21	-	-	-
Y. pestis CO92 Pgm-	0	5	100	1.8 × 104 (7.9 × 103-8.4 × 104)
	3	20	85	1.1 × 102 (0.0-3.2 × 104)
	7	11	100	3.4 × 103 (6.3 × 102-4.9 × 104)
	14	-	-	-
	21	-	-	-
Y. pestis CO92_ΔYPO499-516 Pgm+	0	10	100	3.4 × 103 (2.6 × 102-1.8 × 105)
	3	40	100	1.0 × 103 (1.0-1.8 × 106)
	7	31	96.8	8.1 × 103 (0.0-8.0 × 104)
	14	5	100	1.7 × 103 (1.3 × 103-1.2 × 104)
	21	-	-	-
Y. pestis CO92_ΔYPO499-516 Pgm-	0	10	100	2.7 × 103 (1.7 × 102-1.8 × 104)
	3	40	95	5.7 × 101 (0.0-1.8 × 104)
	7	20	100	1.2 × 103 (2.1 × 101-1.5 × 105)
	14	20	100	2.4 × 102 (1.0 × 101-2.2 × 104)
	21	10	100	9.7 × 102 (2.3 × 102-5.9 × 103)
Y. pestis CO92_Δymt Pgm+	0	10	100	1.4 × 103 (1.0 × 102-9.2 × 103)
	3	26	61.5	1.5 × 101 (0.0-2.6 × 104)
	7	20	75	4.5 × 102 (0.0-7.2 × 104)
	14	4	0	0.0 (0.0-0.0)
	21	-	-	-
Y. pestis CO92_Δymt Pgm-	0	10	100	3.7 × 103 (6.5 × 102-1.8 × 105)
	3	40	30	0.0 (0.0-8.6 × 104)
	7	40	15	0.0 (0.0-5.6 × 101)
	14	40	2.5	0.0 (0.0-3.1 × 103)
	21	20	5	0.0 (0.0-1.4 × 102)
No	0	5	0	0.0 (0.0-0.0)
bacteria	3	40	0	0.0 (0.0-0.0)
	7	33	0	0.0 (0.0-0.0)
	14	40	0	0.0 (0.0-0.0)
	21	20	0	0.0 (0.0-0.0)