Monteiro, Gaby E. R.Bechara, Gervasio Henrique [UNESP]2014-05-202014-05-202008-01-01Animal Biodiversity and Emerging Diseases: Prediction and Prevention. Oxford: Blackwell Publishing, v. 1149, p. 221-225, 2008.0077-8923http://hdl.handle.net/11449/3038The acquisition of resistance in goats against Amblyomma cajennense after repeated infestations and the role of inflammatory cells in this mechanism were investigated. Ten naive goats aged 6 months were distributed into two groups: test (n = 5), infested thrice at 30-day intervals; and control (n = 5), infested once. Nymphs (n = 115 per animal per infestation) were released inside alimentary chambers glued to the animal's dorsum and the following biological parameters were evaluated: yielding rate, nymphal engorgement weight, engorgement period, ecdise rate, and ecdise period. Skin fragments of tick bite sites were collected at 24, 48, 72, and 120 h post attachment for histopathology and inflammatory cells counts. The engorgement weight decreased significantly (P < 0.05) from the first infestation onward; nymphs weighed 41.7% and 37.1% less after the second and third infestations, respectively, as compared to those collected after the first infestation (12.55 mg +/- 3.21). Furthermore, the ecdise period increased significantly (P < 0.05) in the third infestation (18 days +/- 2.83) in comparison with the first infestation (15 days +/- 0.82) and the ecdise rate was significantly lower after the second infestation (71.91% +/- 17.38) in comparison with the first infestation (96.89% +/- 3.38). There were no significant differences with regard to both the engorgement period and yielding rate. A cutaneous basophilia was evidenced between 48 and 72 h (P < 0.05) after both the second and third infestations. We conclude that goats develop resistance against nymphs of A. cajennense and that basophils may play an important role in such a mechanism.221-225engAmblyomma cajennensebiological parameterscutaneous basophiliaGoatsNymphsArtigo10.1196/annals.1428.026WOS:000262400000056Acesso restrito2382374201685423