Comparison of the lifetime host-to-tick transmission between two strains of the Lyme disease pathogen Borrelia afzelii

Table 1 Host-to-tick transmission of B. afzelii and the spirochete load of the infected I. ricinus nymphs are shown for the ten combinations of strain (A3 or A10) and the age of infection (2, 34, 66, 94 and 128 days). The probability of transmission shows the number of infected nymphs divided by the total number of nymphs analysed, and the corresponding percentage of infected nymphs. The spirochete load presents the mean spirochete load and the 95% confidence interval (CI) for the subset of infected nymphs

Strain	Age of infection (days)	Transmission	Spirochete load
Strain	Age of infection (days)	Infected nymphs/total nymphs (%)	Mean^a	95% CI
A3	2	14/105 (13.3)	2,591	1,711–3,924
A3	34	75/100 (75.0)	10,496	8,163–13,496
A3	66	54/95 (56.8)	9,064	7,301–11,251
A3	94	57/90 (63.3)	9,853	7,822–12,411
A3	128	62/90 (68.9)	8,100	6,811–9,633
A10	2	98/190 (51.6)	6,436	5,548–7,465
A10	34	118/130 (90.8)	19,250	17,214–21,528
A10	66	73/118 (61.9)	18,488	15,971–21,402
A10	94	88/128 (68.9)	32,087	28,593–36,009
A10	128	79/128 (61.7)	18,806	17,058–20,735
Total		718/1,174 (61.2)

^aFor each of the ten combinations of strain and age of infection, the geometric mean spirochete load in the nymphal tick was calculated for each mouse (uninfected nymphs were excluded). For strains A3 and A10, the geometric mean nymphal spirochete load and the 95% confidence interval are based on 10 and 13 mice, respectively

ISSN: 1756-3305