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Title: Assessment of sublethal effects of acetylcarvacrol in the oocyte morphology of Rhipicephalus microplus (Canestrini, 1888) and Rhipicephalus sanguineus sensu lato (Latreille, 1806) ticks (Acari: ixodidae)
Other Titles: Avaliação dos efeitos subletais do acetilcarvacrol na morfologia dos ovócitos de carrapatos Rhipicephalus microplus (Canestrini, 1888) e Rhipicephalus sanguineus sensu lato (Latreille, 1806) (Acari: ixodidae)
Authors: Remedio, Rafael Neodini
Peconick, Ana Paula
Remedio, Rafael Neodini
Ferreira, Sidney de Almeira
Mathias, Maria Izabel Camargo
Keywords: Carrapato-de-boi
Carrapato dos bovinos
Sul do Brasil
Cattle tick
Brown dog tick
Southern Brazil
Rhipicephalus microplus
Rhipicephalus sanguineus
Issue Date: 23-Jul-2019
Publisher: Universidade Federal de Lavras
Citation: KONIG, I. F. M. Assessment of sublethal effects of acetylcarvacrol in the oocyte morphology of Rhipicephalus microplus (Canestrini, 1888) and Rhipicephalus sanguineus sensu lato (Latreille, 1806) ticks (Acari: ixodidae). 2019. 98 p. Dissertação (Mestrado em Ciências da Saúde)–Universidade Federal de Lavras, Lavras, 2019.
Abstract: The ticks of the genus Rhipicephalus have two species with wide distribution in Brazil, namely R. sanguineus sensu lato (s. 1) and R. microplus. These ticks are of great medical and veterinary importance for transmitting pathogens to humans and dogs in the case of R. sanguineus (s. 1); and cattle, in the case of R. microplus. In addition, R. microplus is responsible for economic losses in the order of one billion dollars per year, only in Brazil. Therefore, these parasites are targets of different control methods, such as the use of acaricidal substances. Carvacrol, a phenolic monoterpene extracted from plants, shows high acaricidal action. Its semi-synthetic derivative, acetylcarvacrol, has been studied as nematicide, especially since it presents greater efficiency, greater stability and lower toxicity to the hosts, when compared to carvacrol. Based on this information, this study aimed to evaluate the effects of sublethal concentrations of acetylcarvacrol diluted in 3% dimethyl sulfoxide solution (DMSO) in the morphology of the ovaries of R. sanguineus (s. 1) and R. microplus ticks. In order to do this, the ticks were submerged, during five minutes, in different concentrations of acetylcarvacrol, based on previous experiments, according to procedure already established in the literature. After a period of seven days, the ticks were dissected for collection of the ovaries. The material was processed and included in historesin, sectioned, stained and evaluated by means of morphometry and a semiquantitative analysis protocol proposed in this study. The common morphological alterations in the ovaries of R. sanguineus s. l. and R. microplus were cytoplasmic vacuolization, ring-shaped nucleolus, irregular size and shape of germ cells and chorion detachment. For R. sanguineus (s. 1.), there was still a drastic alteration of oviduct epithelial cells, including the disappearance of young germ cells. For both species, higher concentrations of acetylcarvacrol caused statistically significant damages according to the proposed semiquantitative analysis. The results demonstrate the potential of acetilcarvacrol as a method for long-term control of these parasites’ reproduction.
Appears in Collections:DSA - Ciências da Saúde - Mestrado (Dissertações)

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