Mpj. Szabo et Gh. Bechara, Sequential histopathology at the Rhipicephalus sanguineus tick feeding site on dogs and guinea pigs, EXP APPL AC, 23(11), 1999, pp. 915-928
The tick Rhipicephalus sanguineus is a very common parasite of dogs worldwi
de. Dogs seem unable to acquire resistance against this tick species, where
as guinea pigs demonstrate a very strong resistance following primary infes
tation. We studied the inflammatory reaction at the R. sanguineus tick feed
ing site on dogs and guinea pigs during primary and tertiary infestations a
t different time intervals after attachment. Biopsies were collected after
4, 24, 48 and 96 hours. Changes that were found in all experimental groups
included a cone of cement around the mouthparts of the tick, epidermal hype
rplasia, edema and inflammatory cell infiltration in the dermis directly un
derneath the tick attachment site. Dogs reacted to ticks mainly with neutro
phils, particularly after repeated exposure. Mast cells and mononuclear leu
kocytes were also present. Guinea pigs reacted to R. sanguineus mainly with
mononuclear cells, eosinophils and basophils. These cells were particularl
y numerous after repeated exposure to R. sanguineus. Our results suggest th
at basophils and eosinophils are involved in resistance of guinea pigs to R
. sanguineus and that neutrophils in dogs have little effect against this t
ick species.