Eficacia antiparasitaria in vitro del extracto de quebracho (Schinopsis balansae) sobre larvas infectantes de Haemonchus contortus de ovinos / In vitro antiparasitic efficacy of the quebracho extract (Schinopsis balansae) on infecting larvae of Haemonchus contortus of sheep

RESUMEN El objetivo de este trabajo fue evaluar in vitro la eficacia del extracto de quebracho (Schinopsis spp.), rico en taninos condensados, en el control de H. contortus de ovinos, ya que existen evidencias de que estos taninos pueden reducir la excreción de huevos, la fecundidad de las hembras y la carga de parásitos adultos. Para evaluar el efecto antihelmíntico in vitro sobre larvas infectantes de H. contortus susceptibles a todos los grupos químicos, se utilizó el test de inhibición de migración larval (IML) a 3 concentraciones diferentes (5 mg/ml, 15 mg/ml y 30 mg/ml). El efecto de los tratamientos fue analizado mediante un análisis de varianza y la estimación de las diferencias entre grupos se realizó por medio de la prueba LSD Fisher. Los resultados del test in vitro demostraron una reducción de la migración larval que varió entre el 74% y el 80%, a las concentraciones de entre 5 mg/ml y 30 mg/ml. Del análisis de varianza surgen diferencias significativas entre tratamientos (p = 0,0494). Al realizar la prueba de comparación de medias se evidenciaron diferencias significativas (p < 0,05) entre los promedios de migración a las diluciones de 5 mg/ml y 15 mg/ml, y de 5 mg/ml y 30 mg/ml, mientras que no se detectaron diferencias significativas entre la dilución de 15 mg/ml y 30 mg/ml. Estos resultados señalaron que el extracto de quebracho, a las diluciones evaluadas in vitro, presentó actividad antihelmíntica sobre larvas L3 susceptibles de H. contortus. Sin embargo, se requiere ampliar los estudios in vivo para demostrar un efecto antihelmíntico en ovinos.

ABSTRACT The objective of this work was to evaluate in vitro efficacy of the quebracho extract (Schinopsis spp.), rich in condensed tannins, against H. contortus in sheep, since there is evidence that this tanninsthese tannins can reduce egg excretion, fecundity of females and the burden of adult parasites. A larval migration inhibition (IML) test with 3 different concentration (5 mg/ml, 15 mg/ml, and 30 mg/ml) was used to evaluate the in vitro anthelmintic effect upon iInfective H. contortus larvae,from a susceptible strain to all chemical groupswere utilized with 3 diferentconcentration (5mg/ml, 15mg/ml, and 30mg/ml). The effect of the treatments was submitted to a variance analysis and the estimation of the differences between groups was evaluated using LSD Fisher test. Results from the in vitro test, revealed a reduction of the larval migration that varies from 74% to 80%, at the concentrations between 5 mg/ml to 30 mg/ml. From the analysis of variance, significant differences appear between treatments (p = 0,0494). After When performing the mean comparison test were performed, significant differences (p < 0,05) were found between the migration averages at dilutions of 5 mg/ml and 15 mg/ml, and between 5 mg/ml and 30 mg/ml, while were no't detected significant differences between the dilution of 15 mg/ml and 30 mg/ml. These results indicated that quebracho extract at the dilutions evaluated in vitro showed anthelmintic activity on L3 susceptible to H. contortus. However, it is necessary to conduct further studies in vivo to demonstrate an anthelmintic effect in sheep.

PATOLOGÍAS PODALES EN GANADO LECHERO Y EN FEEDLOT DEL PARTIDO DE TANDIL, PROVINCIA DE BUENOS AIRES, ARGENTINA / LAMENESS IN DAIRY CATTLE AND FEEDLOT OF TANDIL COUNTY, BUENOS AIRES PROVINCE, ARGENTINA

Las patologías podales del bovino son multicausales; entre ellas se cuentan altos niveles de producción y estrés, así como etiologías ambientales, nutricionales, infecciosas, genéticas, razas, estado fisiológico y comportamiento, tanto animal como humano. Están adquiriendo gran importancia debido a la intensificación de la producción. El objetivo del presente trabajo fue determinar la prevalencia de enfermedades podales en explotaciones lecheras y en feedlot, así como comparar ambos sistemas de explotación en la región de Tandil, Buenos Aires, Argentina. A tal fin, se evaluaron 24 tambos en 2005 y un feedlot en 2013 en busca de patologías podales. Los animales que presentaron claudicación se separaron del rodeo y se examinaron clínicamente. Se calculó la prevalencia bruta y por patologías de mayor presentación en ambos tipos de explotación y, además, la proporción según miembro afectado. Se estimaron diferencias entre las prevalencias de cada tipo de producción por medio de Chi cuadrado (p < 0,05) y Razón de Prevalencia. La prevalencia en los 12.132 animales lecheros fue de 2,71% y en los 14.500 de feedlot de 0,57% (Razón de Prevalencia = 4,73; IC 95% = 3,72 a 6,02). La prevalencia de traumatismos en feedlot fue del 0,17% y en los tambos de 0,016% (p < 0,05); la de dermatitis digital fue de 0,69% en los tambos y en feedlot de 0,13% (p < 0,05), mientras la prevalencia de dermatitis interdigital alcanzó 0,81% en los tambos y 0,1% en feedlot (p < 0,05). En ambos sistemas de producción, los miembros más afectados fueron los posteriores (90,4% feedlot y 88,1% tambos). La menor prevalencia de patologías podales en feedlot podría deberse a la baja edad de los animales. No obstante, en los animales de feedlot hay una significativa mayor prevalencia en cuanto traumatismos que en los tambos, mientras que en estos se presentan más casos de dermatitis digital e interdigital.

Cattle hoof diseases have multiple causes, including infectious, genetic and environmental, high yield, stress, nutrition, race, physiological condition, and both animal and human behavior. It is gaining importance due to the production intensification. The aim of this study was to determine and compare the prevalence of hoof diseases in dairy farms and feedlots in Tandil county, Buenos Aires Province, Argentina. A total of 24 dairy farms in 2005 and a feedlot in 2013 were included in the study. Animals with claudication were separated from the rodeo and clinically examined. Crude prevalence, prevalence by pathologies and by affected members were calculated. Differences between the prevalence of each production systems by Chi square (p < 0.05) and Prevalence Ratio were estimated. The crude prevalence was 2.71% in dairy farms (12,132 animals), and 0.57% in feedlots (14,500 animals) (Prevalence Ratio = 4.73; 95% CI = 3.72% to 6.02%). The trauma prevalence was 0.17% in feedlots and 0.016% in dairy farms (p < 0.05), digital dermatitis (0.69% dairy, feedlot 0.13%; p < 0.05) and interdigital (0.81% dairy, feedlot 0.1%; p < 0.05). In both productions systems, hind limbs were the most affected (feedlot 90.4% and 88.1% dairy). Low prevalence observed in feedlot could be due to the low animal's age. Trauma was prevalent in feedlot animals while digital and interdigital dermatitis were more common in dairy farms.

Seasonal variation of HUS occurrence and VTEC infection in children with acute diarrhoea from Argentina.

In order to study the seasonality of haemolytic uraemic syndrome (HUS) and verotoxigenic Escherichia coli (VTEC) infection in children, 437 patients under 6 years of age with acute diarrhoea were studied, 8% of whom progressed to HUS. VTEC was found in 10% of all of the stool samples analysed and seasonal occurrence of HUS (p < 0.01) was confirmed. VTEC infection was more prevalent in warm months, although the differences were not statistically significant. Moreover, a significant difference in the detection of O157:H7 serotype and in the vt profile between cold and warm months (autumn and winter; spring and summer, respectively) was established. The O157:H7 serotype was isolated more frequently during warm months. Moreover, a predominance of vt (2) was noted, which was partially replaced by the combination of vt (1) with vt (2) in the cold season. The results of this study indicate the seasonal variation of the disease and the presence of serotype O157:H7 and the vt types. They also reinforce the need to develop prevention programmes considering the seasonal pattern of the disease, which would generate an impact on public health. Control strategies of the pathogen in cattle in the most risky season of the year would also be of benefit.

Occurrence of Shiga toxin-producing E. coli (STEC) on carcasses and retail beef cuts in the marketing chain of beef in Argentina.

Argentina has the highest incidence of HUS in the world. HUS is produced by STEC O157 and non-O157. Cattle's faeces and hides are sources of STEC contamination of carcasses during slaughter. We investigated the presence of STEC in carcasses and cuts of meat in the marketing chain in an agricultural city located in Buenos Aires Province (Argentina). In this study, the detection of the stx gene was used as an indicator of carriage of meat with STEC. In carcasses, we detected 12.34% and 18.64% of STEC at the slaughter and sanitary control cabin (place where carcasses arrive from slaughters located outside the city), respectively. These percentages increased at butcheries (24.52%). The 25% of retail beef cuts were STEC-positive with significant differences among the different cuts of meat (chuck: 12.12%, rump roast: 12.12% and minced beef: 40.74%). The stx2 gene was the predominant gene detected in all samples at different levels of the commercialization meat chain.