RESUMEN
Ten poultry farms (broiler breeder pullets, layer pullets, and broilers) in the provinces of Entre Rios and Buenos Aires in Argentina were examined for presence of Eimeria spp. Litter samples obtained from flocks 7-11 wk old were taken to the laboratory for oocyst counting and sporulation, then concentrated for inoculation into coccidia-free chickens. Species were identified by prepatent period, oocyst size, location and appearance of lesions in the intestine, microscopic examination of mucosal smears, and histology (to confirm Eimeria brunetti). On this basis, Eimeria praecox was found in two samples, Eimeria mitis in two, Eimeria acervulina in nine, Eimeria maxima in seven, Eimeria necatrix in three, Eimeria tenella in seven, and E. brunetti in four. These results confirm the presence of all seven recognized species of Eimeria in chickens in the Republic of Argentina.
Asunto(s)
Pollos/parasitología , Coccidiosis/veterinaria , Eimeria/clasificación , Eimeria/aislamiento & purificación , Mucosa Intestinal/parasitología , Enfermedades de las Aves de Corral/patología , Animales , Argentina , Coccidiosis/epidemiología , Coccidiosis/patología , Heces/parasitología , Femenino , Enfermedades de las Aves de Corral/parasitologíaRESUMEN
Fecal samples from 43 broiler and breeder farms in the Entre Rios and Buenos Aires districts of Argentina were examined for Coccidia. Thirty-eight samples were positive by microscopic examination after salt flotation, with counts of 138 to 415,800 oocysts per gram of feces. Samples were aerated for 2 days and inoculated into 21-day-old chicks for determination of prepatent period. Eimeria praecox was conclusively identified in 56% of the samples by producing typical oocysts (17 x 21 microns) in the feces by 83-90 hr postinoculation (PI). Eimeria mitis was present in 67% of the samples, producing typical oocysts (14 x 15.5 microns) before 95 hr PI. Typical oocysts of Eimeria maxima (20 x 30 microns) and/or typical lesions in the midgut upon necropsy 5-6 days PI were present in 42% of the samples. Eimeria tenella was suspected in 24 of 43 samples on the basis of oocyst size but was confirmed in six samples (14%) at necropsy of infected birds with typical lesions in the ceca (hemorrhage, coagulated blood in the lumen, and thickened cecal mucosa). Characteristic lesions of Eimeria acervulina and ovoid oocysts (14 x 18 microns) were present in all 40 positive samples (93%). Lesions in the lower small intestine of birds inoculated with two of the samples (5%) were typical of Eimeria brunetti. These results confirmed the presence of six species of Coccidia in Argentine poultry (all except Eimeria necatrix, which is known from previous reports) and demonstrated a prevalence and intensity for E. praecox and E. mitis that were previously unreported.
Asunto(s)
Pollos/parasitología , Coccidiosis/veterinaria , Eimeria/aislamiento & purificación , Enfermedades de las Aves de Corral/epidemiología , Animales , Argentina/epidemiología , Coccidiosis/epidemiología , Coccidiosis/patología , Recolección de Datos , Heces/parasitología , Incidencia , Recuento de Huevos de Parásitos/veterinaria , Enfermedades de las Aves de Corral/patología , PrevalenciaRESUMEN
Coccidia were isolated from 90 broiler farms in 15 poultry-producing areas in Brazil and Argentina. Sixty isolates were tested for sensitivity to 7 anticoccidial drugs. The common species were: a) Eimeria tenella, 47 isolates; b) E. maxima, 49 isolates; c) E. acervulina, 44 isolates; d) E. mitis, 26 isolates; and e) E. brunetti, 12 isolates. Isolates were considered sensitive to drugs if intestinal lesion scores of medicated broilers were reduced by at least 50% compared with unmedicated infected broilers or if weight gain was at least 75% of that of uninfected birds in a 6-day laboratory test. According to lesion scores, there was evidence of resistance or seriously reduced sensitivity to monensin in 20 isolates, narasin in 29, salinomycin in 11, maduramicin in 1, clopidol in 36, amprolium in 40, and nicarbazin in 1. According to broiler weight gain, there was resistance to monensin in 36 isolates, narasin in 32, salinomycin in 28, maduramicin in 2, clopidol in 28, amprolium in 50, and nicarbazin in 4. These results suggested incomplete cross resistance of coccidia to polyether ionophorous drugs. The degree of resistance might be explained by previous patterns of use of these drugs.