Thymol: Effects on reproductive biology and Gene's organ morphology in Rhipicephalus sanguineus sensu lato engorged females (Acari: Ixodidae)

Author(s)

Matos, Renata Silva ^{[1, 2]} ; de Oliveira, Patricia Rosa ^[1] ; Coelho, Leticia ^[3] ; Ferreira de Paula, Luiza Gabriella ^[3] ; Zeringota, Viviane ^[3] ; Silva, Bianca Carvalho ^[2] ; Monteiro, Caio ^[4] ; Daemon, Erik ^[2] ; Camargo-Mathias, Maria Izabel ^[1]

Affiliation

^[1] UNESP, Inst Biociencias, Dept Biol, Av 24 A, 1515, Cx Postal 199, BR-13506900 Rio Claro, SP - Brazil

^[2] Univ Fed Juiz de Fora 1, Programa Posgrad Ciencias Biol Comportamento & Bi, Rua Jose Lourengo Kellner S-N, BR-36036330 Juiz De Fora, MG - Brazil

^[3] Univ Fed Goias, Programa Posgrad Ciencia Anim PPGCA, Ave Esperanca S-N, Campus Samambaia, BR-74690900 Goiania, Go - Brazil

^[4] Univ Fed Goicis, IPTSP, Rua 235 S-N, BR-74605050 Goias, Go - Brazil

• Document type: Journal article
• Source: TICKS AND TICK-BORNE DISEASES; v. 11, n. 1 JAN 2020.
• Web of Science Citations: 1

Abstract

Thymol is a monoterpene with proven acaricidal activity on different tick species and life stages. The objective of this work was to evaluate the effect of thymol on the reproductive biology of engorged females of Rhipicephalus sanguineus sensu lato and the morphological changes caused in the cells of the tubular and accessory glands of Gene's organ. The females were exposed to thymol by immersion. Seven groups were established: group I (distilled water), group II (30% ethanol), group III (thymol 1.25 mg/mL), group IV (thymol 2.5 mg/mL), group V (thymol 5.0 mg/mL), group VI (thymol 10.0 mg/mL), and group VII (thymol 20.0 mg/mL), with 20 replicates for each treatment. The ticks were kept in a BOD incubator at 27 +/- 1 degrees C and RH > 80 +/- 10%. Ten females from each group were evaluated daily until death, and the remaining ten were kept in the incubator under the same conditions for five days and then dissected for the removal of Gene's organ to note possible damage to cell morphology by scanning electron microscopy (SEM) and hematoxylin-eosin (HE) techniques. Thymol demonstrated 63% and 98% efficacy in groups VI (10.0 mg/mL) and VII (20.0 mg/mL), respectively. In these groups, the cells of the tubular and accessory glands of Gene's organ showed signs of damage: irregular eosin staining, rupture and deformation of the cellular limit, presence of fragmented nuclei, changes in cytoplasmic homogeneity and areas with deformation (folds) in the basal region. (AU)

• FAPESP's process: 14/13143-7 - Study morphophysiological salivary gland, singânglio, body of ovarian gene and engorged females of R. sanguineus (Latreille, 1806) (Acari: Ixodidae) treated with different concentrations thymol
• Grantee: Renata da Silva Matos
• Support Opportunities: Scholarships in Brazil - Doctorate