Title:	Histopathological alterations in the synganglion of female Rhipicephalus linnaei ticks treated with essential oils of Egletes viscosa and Lippia schaueriana.
Authors:	PEREIRA, M. C. ANHOLETO, L. A. ABREU, M. R. de CASTRO, K. N. de C. CANUTO, K. M. SOUZA, A. S. Q. de CAMARGO-MATHIAS, M. I.
Affiliation:	MELISSA CAROLINA PEREIRA, UNIVERSIDADE ESTADUAL PAULISTA; LUIS ADRIANO ANHOLETO, ACADIA UNIVERSITY; MARINA RODRIGUES DE ABREU, UNIVERSIDADE ESTADUAL PAULISTA; KARINA NEOOB DE CARVALHO CASTRO, CNPGL; KIRLEY MARQUES CANUTO, CNPAT; ANA SHEILA QUEIROZ DE SOUZA; MARIA IZABEL CAMARGO-MATHIAS, UNIVERSIDADE ESTADUAL PAULISTA.
Date Issued:	2026
Citation:	Arthropod-Plant Interactions, v. 20, 47, 2026.
Description:	The inappropriate use of synthetic chemical acaricides for tick management has contributed to the selection of acaricideresistant tick strains, thereby stimulating the search for alternative and effective tick control strategies. Among these, the use of essential oils (EOs) derived from plants such as Egletes viscosa Less. (Asteraceae) and Lippia schaueriana Mart. (Verbenaceae) have shown promise in the control of insects and other arthropods. This study aimed to evaluate the effects of E. viscosa and L. schaueriana EOs on the morphohistology of the tick central nervous system (synganglion)—in Rhipicephalus linnaei semi-engorged females. The morphological alterations in the synganglion were assessed using histopathological and semi-quantitative analyses. The EOs, extracted via hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC–MS), revealed 27 constituents in E. viscosa and 18 in L. schaueriana, with cis-isopinocarveol acetate and piperitenone oxide identified as the predominant compounds, respectively. Histological and semi-quantitative analyses of the synganglion in EO-exposed females revealed dose-dependent alterations that were more severe than the mild vacuolization observed in the ethanol control group, primarily characterized by disruptions in the external membrane structures (neurilemma and perineurium), degeneration of the cortical region with hypertrophic, pyknotic, and fragmented neuronal nuclei, cytoplasmic vacuolization, and neuropil fiber disorganization. These findings suggest that the essential oils of E. viscosa and L. schaueriana induce histopathological damage in the synganglion, including neuronal cell damage and potentially impairing other central nervous system-mediated functions, such as feeding and reproduction. This supports the potential of these oils as candidates for the development of novel plant-based acaricides.
Thesagro:	Carrapato Acaricida Macela Óleo Essencial
Keywords:	Ectoparasita Egletes viscosa Lippia schaueriana Synganglion
DOI:	https://doi.org/10.1007/s11829-026-10256-3
Type of Material:	Artigo de periódico
Access:	openAccess
Appears in Collections:	Artigo em periódico indexado (CNPGL)