title: Evaluation of cytotoxic effects of fipronil on ovaries of semi-engorged Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) tick female.
abstract: The ovary of the Rhipicephalus sanguineus dog tick female is structurally formed by oocytes in five different stages of development (from I to V) and attached to the gonad by the pedicel. The present study evaluated possible toxic effects of the acaricide fipronil (Frontline) on ovaries of semi-engorged ticks. Sixty partially fed females of R. sanguineus tick were distributed into four groups of 15 specimens each: I--non-treated; II, III and IV--treated with 1, 5 and 10 ppm of fipronil, respectively. The acaricide induced structural changes in the oocytes of individuals of the different treated groups ranging from the presence of a few small vacuoles to cellular death. In conclusion, germinative cells of semi-engorged R. sanguineus tick female are affected by different concentrations of fipronil leading to the reduction of tick fertility.
authors.affiliation: Departamento de Biologia, I.B., UNESP, Avenida 24 A, No. 1515, Fone 55 19 35264135, Cx. Postal 199, CEP 13506-900 Rio Claro, SP, Brazil.
authors.forename: Patrícia Rosa
authors.initials: PR
authors.lastname: de Oliveira
authors.forename: Gervásio Henrique
authors.initials: GH
authors.lastname: Bechara
authors.forename: Maria Izabel
authors.initials: MI
authors.lastname: Camargo-Mathias
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D005298:Fertility / Q000187:drug effects; D007306:Insecticides / Q000633:toxicity*; D009865:Oocytes / Q000187:drug effects* / Q000254:growth & development; D010053:Ovary / Q000187:drug effects; D011720:Pyrazoles / Q000633:toxicity*; D011817:Rabbits; D048508:Rhipicephalus sanguineus / Q000187:drug effects* / Q000502:physiology; D013983:Tick Control / Q000379:methods
chemical_list: D007306:Insecticides; D011720:Pyrazoles; C082360:fipronil