Rabbit immunity to the rabbit tick, Haemaphysalis leporispalustris (Acari: Ixodidae). I. The development of resistance

Resistance to ticks, manifested as a reduction in the number of nymphs supported through engorgement, was developed in rabbits subjected to a series of nymphal tick infestations. Resistance appeared in rabbits receiving their initial exposure to nymphal ticks approximately 6 to 10 days after ticks were paced on them. It increased to become maximal between about 10 and 16 days, and then declined if a 2nd group of nymphs was not placed on the rabbits during this time. Although a single infestation of nymphs usually produced resistance, its detection by means of a 2nd infestation thus depended upon the time elapsed between the 2 feedings. The development of the immunity appeared to depend less on the number of ticks per infestation than on the frequency of infestation. A homocytotropic antibody was found in the sera of immune rabbits.