Table 2.

Evaluation of horizontal transmission of Borrelia miyamotoi by Ixodes scapularis larvae or nymphs to naïve Peromyscus leucopus mice, by means of xenodiagnostic larvae PCR-tested for infection after molting to nymphs.

Mouse	Tick challenge	PCR positive challenge ticks recovered	Infected xenodiagnostic ticks by week of feeding after challenge (no. infected/tested)
			Week 1	Week 2	Week 3	Week 4	Weeks 1–4 combined
1	larvae	1	0/22	1/21	0/14		1/57
2	larvae	2		0/16	0/13	0/30	0/59
3	larvae	6	0/17	0/7	0/21		0/45
4	larvae	2	1/14	0/4	0/11		1/29
5	larvae	1	0/9	0/4	0/13		0/26
6	larvae	1	2/25	0/5	0/17		2/47
7	larvae	2	0/27	0/14	0/9		0/50
8	larvae	2	0/25	0/8	0/12		0/45
9	larvae			0/20	0/6	1/16	1/42
Total from positive (xenodiagnostic) mice (n = 4)							5/175 (2.9%)
Total from mice exposed to infected larvae (n = 9)			3/139 (2.2%)	1/99 (1.0%)	0/116 (0%)	1/46 (2.2%)	5/400 (1.3%)
11	nymphs	1	0/15	0/6	0/9		0/30
13	nymphs	2	0/28	0/18	0/4		0/50
14	nymphs	3	0/16	0/8	0/21		0/45
15	nymphs	2	0/22	0/16	0/25		0/63
16	nymphs	4	0/9	0/24	0/9		0/42
17	nymphs	1	0/26	0/18	0/50		0/94
18	nymphs	4	1/9	1/6	1/23		3/38
Total from mice exposed to infected nymphs (n = 7)			1/125 (0.8%)	1/96 (1%)	1/141 (0.7%)		3/362 (0.8%)
12	nymphs	0	0/9	0/5	0/5		0/19
19	nymphs	0	0/33	0/9	0/5		0/47
Total from mice exposed to negative nymphs (n = 2)