info:eu-repo/semantics/article
Field trial assessment of ivermectin pharmacokinetics and efficacy against susceptible and resistant nematode populations in cattle
Fecha
2018-05Registro en:
Cantón, Candela; Cantón, Lucila; Dominguez, Maria Paula; Moreno Torrejon, Laura; Lanusse, Carlos Edmundo; et al.; Field trial assessment of ivermectin pharmacokinetics and efficacy against susceptible and resistant nematode populations in cattle; Elsevier Science; Veterinary Parasitology; 256; 5-2018; 43-49
0304-4017
CONICET Digital
CONICET
Autor
Cantón, Candela
Cantón, Lucila
Dominguez, Maria Paula
Moreno Torrejon, Laura
Lanusse, Carlos Edmundo
Alvarez, Luis Ignacio
Ceballos, Laura
Resumen
The study compared the pharmacokinetic (PK) behaviour and anthelmintic efficacy against susceptible and resistant nematodes following subcutaneous (SC) and oral administration of ivermectin (IVM) to cattle. Six commercial farms were involved: Farms 1 and 2 (IVM-susceptible nematode population) and Farms 3, 4, 5 and 6 (IVM-resistant nematode population). On each farm, forty-five calves naturally infected with gastrointestinal (GI) nematodes were randomly allocated into three groups (n = 15): untreated control, IVM SC administration, and IVM oral administration (both at 0.2 mg/kg). PK assessment (plasma and faeces) was performed on Farm 1. Efficacy was determined by Faecal Egg Count Reduction Test. IVM systemic availability upon SC administration (421 ± 70.3 ng·d/mL) was higher (P < 0.05) compared to the oral treatment (132 ± 31.3 ng·d/mL). However, higher (P < 0.05) faecal IVM concentrations were observed following oral treatment (9896 ± 1931 ng·d/mL) compared to SC administration (4760 ± 924 ng·d/mL). Similar (91–93%) IVM efficacy was observed on Farms 1 and 2 by both routes. Efficacy against resistant nematodes was slightly higher on Farms 3 and 4 after the oral (63 and 82%, respectively) compared to the SC (36 and 68%, respectively) treatment. However, there was complete therapeutic failure (0% efficacy) on Farm 5 and a very low response on Farm 6 (40 and 41% for SC and oral administration, respectively). Although larger faecal concentrations following IVM oral administration may increase drug exposure of GI adult worms, this does not always improve efficacy against resistant nematodes. The potential therapeutic advantages of oral treatments should be cautiously assessed, especially in presence of anthelmintic resistance.