Anticoccidial sensitivity profiles of recently obtained Dutch, German, and Spanish Eimeria spp. isolates
H.W. Peek and W.J.M. Landman
h.peek@gdvdieren.nl
Animal Health Service Ltd., P.O. Box 9, 7400 AA Deventer, the Netherlands
Abstract
Anticoccidial sensitivity profiles of thirty nine Eimeria spp. field isolates
collected from broiler farms between 1996 and 2002 were determined. The tested
products were: diclazuril (ClinacoxÒ: 1 mg/kg), halofuginone (StenorolÒ: 3
mg/kg), lasalocid (AvatecÒ: 90 mg/kg) , maduramycin (Cygro®: 5 mg/kg),
meticlorpindol/methylbenzoquate (LerbekÒ: 100 mg/kg), monensin (ElancobanÒ:
100 mg/kg), narasin ((MontebanÒ: 70 mg/kg), narasin/nicarbazin (MaxibanÒ:
40/40 mg/kg), nicarbazin (NicarbÒ: 125 mg/kg), robenidine (RobenzÒ: 33 mg/kg)
and salinomycin (SacoxÒ: 60 mg/kg). The tests were performed in battery cages.
The sensitivity profile of each Eimeria spp. present in the field isolates was
based on the reduction of the mean lesion score of the infected medicated group
as compared to the infected unmedicated birds. A reduction percentage of 0-30%
indicates resistance, 31-49% reduction indicates reduced sensitivity, and 50% or
more indicates full sensitivity. Most field isolates (n = 21) consisted of
mixtures of two or three Eimeria spp., while eighteen isolates comprised a
single species (E. acervulina n = 16; E. maxima and E. tenella in the other
cases). Regarding the distribution of species, E. acervulina was most frequently
found (n = 37) followed by E. maxima (n = 15) and E. tenella (n = 12). Almost
all Eimeria spp. found in the field isolates showed resistance or decreased
sensitivity against the selected anticoccidial drugs. Exceptions were some
Eimeria acervulina strains, which were sensitive to diclazuril (2/30),
meticlorpindol/methylbenzoquate (17/19), monensin (3/20), narasin (5/25),
narasin/nicarbazin (1/16), nicarbazin (3/30), robenidine (3/6) and salinomycine
(11/36). All E. acervulina isolates tested against halofuginone (n =16),
lasalocid (n =19) and maduramycin (n = 4) showed resistance or decreased
sensitivity. Some E. maxima strains showed sensitivity to diclazuril (1/11),
halofuginone (4/5), meticlorpindol/methylbenzoquate (6/9), narasin (2/8),
narasin/nicarbazine (5/8), nicarbazin (4/13), robenidine (1/1), and salinomycin
(3/14). All E. maxima isolates tested for lasalocid (n = 3), maduramicin (n = 1)
and monensin (n = 6) showed resistance or decreased sensitivity. A number of E.
tenella strains were sensitive to diclazuril (4/11), halofuginone (3/3),
lasalocid (2/8), maduramycin (1/1), meticlorpindol/methylbenzoquate (7/7),
monensin (1/8), narasin (2/10), nicarbazin (2/11), robenidine (1/1), and
salinomycin (1/12). All E. tenella isolates (n = 4) tested for narasin/nicarbazin
showed resistance. The present study shows that resistance against most
anticoccidial drugs, except meticlorpindol/methylbenzoquate, is fairly common
amongst European coccidiosis field isolates.