Evaluation of cytotoxic effects of fipronil on ovaries of semi-engorged Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) tick female.
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.
de Oliveira
Patrícia Rosa
PR
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.
Bechara
Gervásio Henrique
GH
Camargo-Mathias
Maria Izabel
MI
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
D007306:Insecticides; D011720:Pyrazoles; C082360:fipronil