title: Cutaneous basophilia in the resistance of goats to Amblyomma cajennense nymphs after repeated infestations.
abstract: The 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.
authors.affiliation: Faculdade de Veterinária, Universidade Eduardo Mondlane, Maputo, Mozambique.
authors.forename: Gaby E R
authors.initials: GE
authors.lastname: Monteiro
authors.forename: Gervásio H
authors.initials: GH
authors.lastname: Bechara
mesh_terms: D000818:Animals; D001491:Basophils / Q000166:cytology / Q000276:immunology*; D005260:Female; D006041:Goats / Q000276:immunology*; D008297:Male; D012871:Skin Diseases / Q000276:immunology* / Q000473:pathology; D013987:Ticks / Q000254:growth & development / Q000502:physiology*