Efficacy of fipronil (1.0mg/kg) against Rhipicephalus (Boophilus) microplus strains resistant to ivermectin (0.63mg/kg)
| Autor: | Alvirnar Jose da Costa, Carolina Buzzulini, Breno Cayeiro Cruz, Gilson Pereira de Oliveira, Flávia Carolina Fávero, Murilo Abud Bichuette, Vando Edésio Soares, Weslen Fabricio Pires Teixeira, Gustavo Felippelli, Willian Giquelin Maciel, Lucas Vinicius Costa Gomes, Welber Daniel Zanetti Lopes |
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| Rok vydání: | 2014 |
| Předmět: |
Veterinary medicine
medicine.medical_treatment Drug Resistance Cattle Diseases Biology Tick chemistry.chemical_compound Ivermectin Food Animals Rhipicephalus medicine Animals Saline Acaricides Fipronil Pesticide Saline water biology.organism_classification Tick Infestations chemistry Herd Pyrazoles Cattle Female Animal Science and Zoology Brazil medicine.drug |
| Zdroj: | Preventive Veterinary Medicine. 115:88-93 |
| ISSN: | 0167-5877 |
| Popis: | The present study aimed to evaluate the efficacy of fipronil (1 mg/kg) against three strains of ivermectin-resistant Rhipicephalus (Boophilus) microplus (R. (B.) microplus), naturally infesting cattle from different states of Brazil. Three rural properties with a history of macrocyclic lactones ineffectiveness against the cattle tick, and low frequency use of fipronil in the herd, were selected for the study. The animals were randomized according to the mean tick counts, performed on days -3, -2 and -1, into three groups with 10 animals each: T01, control (saline solution); T02, subcutaneous ivermectin (0.63 mg/kg) and T03, topical fipronil (1 mg/kg). Treatment was performed on day 0. Counts of partially engorged female ticks were performed on days 3, 7 and 14 post-treatment (DPT), and then every 7 days until the 49th DPT. In all three experiments, it was possible to diagnose resistance of R. (B.) microplus to ivermectin (0.63 mg/kg). The maximum efficacy (arithmetic mean) obtained for ivermectin was 64% in experiment II. On the other hand, the formulation containing fipronil (1 mg/kg) reached high efficacy values (≥97%) in all three experiments. The results from all experiments in this study demonstrate the high efficacy of 1mg/kg fipronil, administered pour-on in naturally infested cattle, against strains of R. (B.) microplus that are resistant to 630 mcg/kg ivermectin. |
| Databáze: | OpenAIRE |
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