Comparison of feeding success of larval Ixodes Scapularis and I. Ricinus, the main vector tick species of Borrelia spp. using mice as host

Purpose: Several ticks of the genus Ixodes such as Ixodes scapularis and I. ricinus are among the most important vectors of Lyme disease pathogens. Studies focused on tick-host-pathogen interactions in Lyme borreliosis requires robust animal models. Mice are used most frequently as hosts for this purpose because they are the natural biological reservoirs for Borrelia spp. The objective of this study was to develop a standardised and reproducible protocol for feeding I. scapularis and I. ricinus tick larvae on mice Methods & Materials: Twenty Swiss mice aged 10 weeks with a body weight >25 g were allocated into two groups of 10 each. After sedation, mice from group 1 and 2 were infested with 100 pathogen-free I. ricinus and I. scapularis larvae each, respectively. The attachment success was assessed one hour after infestation while the feeding success was determined from the total number of engorged larvae that dropped off the mouse 48, 72, 96 and 120 h after infestation Results: Attachment rate was 96.9% and 77.5% for I. ricinus and I. scapularis, respectively. Cumulative feeding success assessed 48, 72, 96 and 120 h after infestation was 3.3, 34.6, 42.3 and 42.3% and 0, 5.7, 33.3 and 40.7% for I. ricinus and I. scapularis, respectively. There was no significant difference (χ2 test, p˃0.05) between I. ricinus and I. scapularis for both attachment and feeding rate success Conclusion: Our infestation procedures provide a simple protocol for feeding larval Ixodes spp. on mice. This tick infestation model was regarded suitable for potential future research on tick-host-pathogen interactions as well as to evaluate the effectiveness of host-targeted acaricides against immature I. ricinus and I. scapularis ticks