Reaction of the host to the tick bite III. The bite of viruliferous Ixodes ricinus female.

No distinct internal cement formation was observed at the penetration site of the mouth parts of Ixodes ricinus females during their feeding on golden hamsters. At 2 h, the chelicera were already deeply inserted into the dermal tissue. Beginning after 4 hours, the proliferation of collagen and conus formation became evident. The internal cell-free area was structureless and showed PAS positivity, while the outer collagen layer was rich in fibrocytes and negative for PAS staining. Both layers showed positivity when stained for collagen. The conus extending into the subdermal connective tissue was surrounded by an infiltrate of mononuclear and polynuclear leukocytes. The half-engorged females showed specific fluorescence of the TBE antigen in columnar epidermal cells. The penetration of the TBE virus into host tissue lasted probably only for a few hours, as virus was succesfully transmitted to golden hamsters during 2 h feeding of the viruliferous I. ricinus females.