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Updated: Oct 12, 2026
Feeding of Ticks on Animals for Transmission and Xenodiagnosis in Lyme Disease Research
Published on: August 31, 2013
Dermacentor variabilis: resistance to ticks acquired by mast cell-deficient and other strains of mice
Abstract:
The acquisition of resistance to ticks was monitored in mice of six different strains. Mice were subjected to repeated infestations with Dermacentor variabilis larvae, different skin sites being used for each successive infestation. In the third and fourth infestations, resistance was expressed in three strains of mice (WBB6F1-W/Wv, WBB6F1-+/+, and CFW), as demonstrated by significant reductions in percentages of larvae engorging and in mean weights of fed larvae. Both WBB6F1-W/Wv mice, which are mast cell-sufficient strain attained significantly higher levels of resistance. It is suggested that mast cells may play a relatively minor role in the mechanisms of resistance in this strain of mice. C57B1 mice also expressed tick resistance in their third and fourth infestations as measured by reduced percentages of engorged larvae, but not by reduced mean larval weights. Possibly, the mechanisms of tick resistance in this strain differ from those in other strains. Two other mouse strains (C3H-HeJ and C3H-HeSn) remained relatively susceptible to tick feeding throughout five infestations. In secondary infestations of all strains tested, no resistance was evident. Instead, enhanced feeding of larvae appeared to occur. A new objective measurement of tick resistance is the mean weights of detached, unengorged larvae taken from resistant animals at the end of the infestation period. These were found to be consistently less than those from susceptible animals.
Insights
Mice developed resistance to tick feeding by the third infestation, with varying effectiveness across strains. Resistance was measured by reduced larval engorgement and weight, suggesting complex immune mechanisms.
Area of Science:
- Immunology
- Parasitology
- Mammalian Genetics
Background:
- Tick infestations pose challenges in disease transmission and host-parasite interactions.
- Understanding host resistance mechanisms is crucial for developing effective control strategies.
- Mouse models are valuable for studying host-parasite dynamics and immune responses.
Purpose of the Study:
- To investigate the acquisition of resistance to Dermacentor variabilis tick larvae in different mouse strains.
- To evaluate the role of host genetics in modulating tick resistance.
- To identify objective measurements for assessing tick resistance.
Main Methods:
- Repeated infestations of six different mouse strains with Dermacentor variabilis larvae.
- Monitoring larval engorgement rates and larval weights post-infestation.
- Assessing resistance based on reductions in larval engorgement and weight.
- Analyzing detached, unengorged larvae as a novel resistance metric.
Main Results:
- Three mouse strains (WBB6F1-W/Wv, WBB6F1-+/+, CFW) exhibited significant tick resistance by the third and fourth infestations.
- WBB6F1-W/Wv mice showed higher resistance levels, suggesting a minor role for mast cells.
- C57B1 mice displayed resistance via reduced engorgement but not larval weight, indicating potentially different mechanisms.
- C3H-HeJ and C3H-HeSn strains remained susceptible throughout five infestations.
- Secondary infestations did not elicit resistance; instead, enhanced larval feeding was observed.
- Mean weights of detached, unengorged larvae were consistently lower in resistant mice.
Conclusions:
- Mouse strains vary in their ability to acquire resistance to Dermacentor variabilis larvae.
- Tick resistance acquisition is typically observed from the third infestation onwards.
- Reduced larval weight and engorgement are key indicators of tick resistance.
- Detached, unengorged larval weight offers a new, objective measure of host resistance.
