Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Dec 14;123(1):48.
doi: 10.1007/s00436-023-08037-5.

Do combinations of fipronil, eugenol and carvacrol have synergistic effects against Rhipicephalus sanguineus?

Fernando Rocha Miranda  1 , Barbara Rauta Avelar  1 , Ingrid Lins Raquel de Jesus  1 , Brena Gava Guimarães  1 , Isabelle Vilela Bonfim  1 , Melina Cardilo Campos Alves  1 , Thais Paes Ferreira  2 , Thais Ribeiro Correa Azevedo  1   2 , Yara Peluso Cid  3   4 , Fabio Barbour Scott  1   2
Affiliations

Do combinations of fipronil, eugenol and carvacrol have synergistic effects against Rhipicephalus sanguineus?

Fernando Rocha Miranda et al. Parasitol Res. .

Abstract

The tick Rhipicephalus sanguineus is one of the main ectoparasites that affects dogs, causing direct and indirect damage to parasitized animals. Currently, infestation control is mainly carried out by using synthetic acaricidal drugs. However, a decrease in efficacy and an increase in resistance to the main therapeutic protocols against tick infestations have been increasingly reported and confirmed, a factor that has driven research into the potential acaricide activity of natural compounds, including in association with synthetic molecules. The aim of this work was to evaluate whether the combinations of fipronil (FIP) and eugenol (EUG), FIP and carvacrol (CAR), and EUG and CAR would have synergistic effects against immature and unfed adult stages of R. sanguineus through in vitro bioassays. Bioassays were carried out using the larval packet test (FAO 2004) adapted for nymphs and adults. The synergistic activity was explored by combining each solution, based on the estimated LC50, in a 1:1 ratio (FIP: EUG, FIP: CAR and EUG: CAR). CompuSyn software was used to evaluate the various pairwise combinations of FIP, EUG and CAR, checking if there was synergism or antagonism between them. FIP and EUG and FIP and CAR showed combination index (CIn) values above 1.45, indicating antagonism. The synergistic activity between EUG and CAR was verified against all unfed phases of R. sanguineus, since the CIn was below 0.70, a value that indicates synergism. The combination of fipronil with either eugenol or carvacrol presented antagonistic effects against R. sanguineus larvae. On the other hand, carvacrol and eugenol had excellent pharmacological synergism against all tick stages with mortality values in the range of 80 to 100%, including the adult stage, which is less susceptible than immature stages.

Keywords: Control; Monoterpene; Phenylpropanoid; Synergism; Tick.

PubMed Disclaimer

References

    1. Abbott WS (1987) A method of computing the effectiveness of an insecticide. 1925. J Am Mosq Control Assoc 3(2):302–303
    1. Alves FM, Bernardo CC, Paixão FR, Barreto LP, Luz C, Humber RA, Fernandes ÉK (2017) Heat-stressed Metarhizium anisopliae: Viability (in vitro) and virulence (in vivo) assessments against the tick Rhipicephalus sanguineus. Parasitol Res 116:111–121. https://doi.org/10.1007/s00436-016-5267-z - DOI - PubMed
    1. Adhikari K, Khanikor B, Sarma R (2022) Persistent susceptibility of Aedes aegypti to eugenol. Sci Rep 12(1):2277 - DOI - PubMed - PMC
    1. Araújo LX, Novato TPL, Zeringota V, Maturano R, Melo D, Da Silva BC, Daemon E, De Carvalho MG, Monteiro CMO (2016) Synergism of thymol, carvacrol and eugenol in larvae of the cattle tick, Rhipicephalus microplus, and brown dog tick, Rhipicephalus sanguineus. Med Vet Entomol 30(4):377–382. https://doi.org/10.1111/mve.12181 - DOI - PubMed
    1. Baggott D, Ollagnier C, Yoon SS, Collidor N, Mallouk Y, Cramer LG (2011) Efficacy of a novel combination of fipronil, amitraz and (S)-methoprene for treatment and control of tick species infesting dogs in Europe. Vet Parasitol 179(4):330–334. https://doi.org/10.1016/j.vetpar.2011.03.045 - DOI - PubMed

LinkOut - more resources