article · Insects
This study investigated ivermectin resistance in *Rhipicephalus annulatus* tick populations from five localities in Beni-Suef province, Egypt. Using a larval immersion test with various ivermectin concentrations, researchers found significant differences in lethal concentrations (LC50 and LC90) among the populations. Ticks from Emin elaros and Aldiabia exhibited higher LC50 and LC90 values, alongside a history of acaricide failure, indicating they had developed resistance to ivermectin. This research marks the first documented report of ivermectin-resistant *R. annulatus* in Egyptian field populations, highlighting a growing challenge in tick control.
The emergence of ivermectin resistance in cattle ticks poses a significant threat to livestock health and agricultural productivity. Effective tick control is crucial for preventing disease transmission and economic losses. This finding highlights the urgent need for updated control strategies to manage resistant tick populations and protect animal welfare.
This research provides critical information for veterinary practitioners and livestock farmers in Egypt, informing decisions on effective tick control programmes. Recognising ivermectin resistance means current treatments may fail, necessitating the development or adoption of alternative acaricides or integrated pest management strategies. This is an early-stage finding, directly impacting the efficacy of existing commercial products and guiding future research into new control methods.
AI-generated from the published abstract. Always read the original work before citing.
Tick control is mainly dependent on the application of acaricides, but resistance has developed to almost all classes of acaricides, including macrolactones. Therefore, we aimed to investigate ivermectin resistance among tick populations in middle Egypt. The larval immersion test was conducted using a commercial formulation of ivermectin (1%). Different concentrations of the immersion solution (0.0000625% (625 × 10<sup>-7</sup>%), 0.000125% (125 × 10<sup>-6</sup>%), 0.0005% (5 × 10<sup>-4</sup>%), 0.001% (1 × 10<sup>-3</sup>%), 0.0025% (2.5 × 10<sup>-3</sup>%), 0.005% (5 × 10<sup>-3</sup>), and 0.01% (1 × 10<sup>-2</sup>%)) were prepared by diluting a commercial ivermectin (1%) with distilled water containing 1% (<i>v</i>/<i>v</i>) ethanol and 2% (<i>v</i>/<i>v</i>) TritonX-100. Field populations of <i>Rhipicephalus annulatus</i> were collected from five different localities in Beni-Suef province, Egypt. Adult engorged female ticks were collected and assessed for oviposition and egg fertility. Eggs were collected, and hatched larvae were then used in the experiment. Application of acaricides was conducted on 10-day-old larvae. There was a significant difference in the LC<sub>50</sub> (50% lethal concentration) among the examined localities on the log dose-response plot, where, the LC<sub>50</sub> of tick populations from two localities (Emin elaros and Aldiabia) was higher than the other localities (Alhalabia, Alkom, and Beshnna). Besides, tick populations from Emin elaros and Aldiabia showed higher LC<sub>90</sub> values with lower slope values compared to those from Alhalabia, Alkom, and Beshnna. According to these values (LC<sub>50</sub>, LC<sub>90</sub>, and slope values), as well as a history of acaricide failure to ticks in these areas, <i>R. annulatus</i> developed resistance to ivermectin. This study documents the first report of field populations of <i>R. annulatus</i> resistant to ivermectin in Egypt.
This page summarises published work. The authoritative version sits with the publisher.
DOI: 10.3390/insects10110404
Is something wrong with this record? Report it or request removal.
Discussion
Have you built on this work, tried to replicate it, or seen it applied in practice? Share what you know. Verified researchers and MARATTO™ domain experts can open a discussion, and any member can reply. Contributions are reviewed before they appear.
No discussion yet. Open the first thread.
New to MARATTO™? Create a free account.
