Higher Incidence of Eimeria spp. Field Isolates Sensitive for Diclazuril and Monensin Associated with the Use of Live Coccidiosis Vaccination with Paracox registered -5 in Broiler Farms

• Published in: Avian diseases 2006-09, Vol.50 (3), p.434-439
• Main Authors: Peek, H W, Landman, WJM
• Format: Article
• Language: English
• Subjects: Eimeria acervulina; Eimeria maxima; Eimeria tenella
• ISSN: 0005-2086
• DOI: 10.1637/7486-121205R.1

Twenty European Eimeria spp. field isolates were subjected to an anticoccidial sensitivity test (AST). The anticoccidial drugs tested were diclazuril (Clinacox super( registered )) and monensin (Elancoban super( registered )). The assay was performed in a battery cage trial. Infected medicated birds were compared with an unmedicated control group. Coccidial lesion scores and oocyst shedding were used as parameters. The results of the AST show that resistance is common amongst coccidiosis field isolates, especially Eimeria acervulina (68% and 53% resistance for diclazuril and monensin, respectively). Resistance is less frequent amongst Eimeria maxima (38% and 50% resistance for diclazuril and monensin, respectively) and Eimeria tenella isolates (23% and 38% resistance for diclazuril and monensin, respectively). A highly significant influence of the coccidiosis prevention program (live coccidiosis vaccination with Paracox registered -5 vs. anticoccidial drugs in feed) on the sensitivity patterns of Eimeria spp. field isolates for both diclazuril (P = 0.000) and monensin (P = 0.001) was found. Further, when looking at the single species and each anticoccidial drug level, significantly more sensitivity of E. acervulina for monensin (P = 0.018), E. maxima for diclazuril (P = 0.009), and E. tenella for diclazuril (P = 0.007) was found in isolates originating from vaccinated flocks. Moreover, for E. acervulina and diclazuril, E. maxima and monensin, and E. tenella and monensin a trend toward higher sensitivity of isolates for these products was found when live coccidiosis vaccination was applied. The present study shows that sensitivity for the anticoccidial drugs diclazuril and monensin is more frequent in Eimeria spp. field isolates originating from broiler farms where a coccidiosis vaccination policy is followed.Original Abstract: Nota de Investigacion-Mayor incidencia de aislamientos de campo de Eimeria spp. sensibles al diclazuril y a la monensina, asociada a la vacunacion contra la coccidiosis utilizando Paracox registered -5 en granjas de pollos de engorde.Se realizo una prueba de sensibilidad anticoccidial en veinte aislamientos de campo Europeos de Eimeria spp. Las drogas anticoccidiales analizadas fueron el diclazuril (Clinacox super( registered )) y la Monensina (Elancoban super( registered )). La prueba se realizo alojando las aves en jaulas. Se compararon aves infectadas medicadas con un grupo control no medicado. Se utilizaron los registros de lesio