ABSTRACT Seven sites were examined in the Challhuaco-Ñireco system, located in the reserve of the Nahuel Huapi National Park, however part of the catchment is urbanized, being San Carlos de Bariloche (150,000 inhabitants) placed in the lower part of the basin. Physico-chemical variables were measured and benthic macroinvertebrates were collected during three consecutive years at seven sites from the headwater to the river outlet. Sites near the source of the river were characterised by Plecoptera, Ephemeroptera, Trichoptera and Diptera, whereas sites close to the river mouth were dominated by Diptera, Oligochaeta and Mollusca. Regarding functional feeding groups, collector-gatherers were dominant at all sites and this pattern was consistent among years. Ordination Analysis (RDA) revealed that species assemblages distribution responded to the climatic and topographic gradient (temperature and elevation), but also were associated with variables related to human impact (conductivity, nitrate and phosphate contents). Species assemblages at headwaters were mostly represented by sensitive insects, whereas tolerant taxa such as Tubificidae, Lumbriculidae, Chironomidae and crustacean Aegla sp. were dominant at urbanised sites. Regarding macroinvertebrate metrics employed, total richness, EPT taxa, Shannon diversity index and Biotic Monitoring Patagonian Stream index resulted fairly consistent and evidenced different levels of disturbances at the stream, meaning that this measures are suitable for evaluation of the status of Patagonian mountain streams.

RESUMEN Siete sitios fueron examinados en el sistema lótico Challhuaco-Ñireco, ubicado dentro del Parque Nacional Nahuel Huapi (PNNH), sin embargo parte de esta cuenca está urbanizada ya que atraviesa la ciudad de San Carlos de Bariloche (150,000 habitantes). Se midieron variables físico-químicas y se colectaron los macroinvertebrados bentónicos durante tres años consecutivos en siete sitios desde la cabecera hasta la desembocadura. Plecoptera, Ephemeroptera, Trichoptera y Diptera predominaron en los sitios cercanos a la cabecera, mientras que Diptera, Oligochaeta y Mollusca dominaron los sitios más bajos cercanos a la desembocadura. En relación con los grupos funcionales, los colectores-recolectores fueron los dominantes en todos los sitios y este patrón fue consistente durante los tres años de muestreo. El análisis de ordenamiento (RDA) reveló que las distribuciones de los ensambles de especies respondieron al gradiente climático y topográfico (temperatura y elevación), pero también fueron asociados con variables relacionadas al impacto antrópico (conductividad, contenido de nitratos y fosfatos). Los ensambles en cabecera estuvieron representados por insectos sensibles, mientras que los taxones tolerantes como Tubificidae, Lumbriculidae, Chironomidae y el crustáceo Aegla sp. fueron dominantes en los sitios urbanizados. En relación con las métricas analizadas, la Riqueza total, el EPT taxa, la diversidad de Shannon y el índice biótico BMPS evidenciaron diferentes niveles de disturbio en el sistema, demostrando que estas medidas son una excelente herramienta para determinar el estado de los ríos de montaña de la Patagonia.

Os objetivos deste trabalho foram determinar a prevalência de enterite fibrinonecrótica (EFN) em uma granja tecnificada com 1000 matrizes, classificar as mudanças patológicas e investigar a lesão decorrente da associação dos agentes Clostri-dium perfringens e Isospora suis. As lesões macroscópicas devidas à mortalidade pré-desmame (MPD) foram classificadas em oito categorias incluindo EFN. Os dados obtidos foram avaliados pelo teste Qui-quadrado. Amostras de EFN foram colhidas para estudos complementares incluindo uma técnica de reação em cadeia da polimerase (PCR) para identificação dos genes codificadores de toxinas de C. perfringens a partir de amostras do intestino fixadas em formalina a 10%. Dos 3.153 leitões examinados, menos que 1% foram classificados como EFN. As análises estatísticas revelaram que a EFN aumentou progressivamente a partir da primeira para a terceira semana, sendo que a última semana diferiu estatisticamente das demais. Oitenta porcento das amostras do intestino com EFN foram positivas para I. suis. Por meio da PCR a partir dos 9 casos de EFN severa, 7 foram positivos somente para o gene da toxina alfa, característico de C. perfringens tipo A.

The objectives were to determine the prevalence of fibrinonecrotic enteritis (FNE) on a farrow-to-finish farm of 1,000 sows, to categorize the pathological changes, and to to investigate the lesion associated agents Isospora suis and Clostridium perfringens. Causes of preweaning mortality (PWM) were classified into 8 categories including FNE. Obtained data were evaluated for statistical significance by adjusted Chi-square analysis. Samples of FNE were taken for complementary studies including a PCR technique for genotyping toxin genes of Clostridium perfringens from gut samples fixed in 10% neutral formalin. From 3,153 piglets examined, less than 1% was classified as FNE. FNE prevalence increased progressively from the first to the third week, the last differing statistically from the others. Eighty percent of gut samples with FNE lesions were positive to Isospora suis, when examined by PCR from 9 severe FNE lesions detected 7 positive samples only for a toxin gene, characteristic of C. perfringens type-A.

The following techniques of fecal examination for parasite detection were evaluated comparatively: Sheater modified (flotation by sugar solution), Zinc sulfate (flotation by this salt solution) and Ritchie modified (sedimentation with formalin-saline solution and fats extraction by ether). Parasites were detected in 25 of 40 fecal samples of dogs examined by the three techniques. There were no differences among the techniques of Sheater and Zinc sulfate in the quantity of detections (37 and 38 respectively) but the corresponding value to formalin-ether (16) was significantly smaller. The quantities of eggs of Toxocara canis and Trichuris vulpis (213 and 334 respectively) detected by Sheater in fresh feces were significantly greater than those corresponding to zinc sulfate (44 and 13 respectively). The results were similar for fecal samples with eggs of T. vulpis and formalin (Sheater: 61 vs zinc sulfate: 0). The quantities of cysts of Giardia detected by formalin-ether in feces with and without formalin were significantly greater than those corresponding to zinc sulfate (19 and 87 vs 3 and 36 respectively). In 180 samples examined, the quantity of detections of Giardia sp. was significantly greater by the formalin-ether technique, than by that of Sheater (15 vs 1, respectively). The technique of Sheater was more efficient than that of zinc sulfate for the detection of nematode eggs while that of formalin-ether was more efficient for the detection of Giardia sp cysts. On agreement with the results, it is recommended that, unless special indications, each sample that requires parasitological examination should be processed by both techniques: that of Sheater and that of formalin-ether

Se evaluaron comparativamente las siguientes técnicas para el examen parasitológico de heces de perro: la técnica de Sheater modificada (flotación por la solución de azúcar), la de sulfato de zinc (flotación por la solución de esta sal) y la de Ritchie modificada, denominada también de formol-éter (sedimentación con solución salina formolada y extracción de grasas por éter). Se detectaron parásitos en 25 de 40 muestras de materia fecal de perros que se examinaron por las tres técnicas. No hubo diferencias entre las técnicas de Sheater y sulfato de zinc en la cantidad de detecciones logradas (37 y 38 respectivamente) pero el valor correspondiente a la de formol-éter (16) fue significativamente menor. Las cantidades de huevos de Toxocara canis y Trichuris vulpis (213 y 334 respectivamente) detectadas por Sheater en materia fecal en fresco, fueron significativamente mayores que las correspondientes a sulfato de zinc (44 y 13 respectiva mente). Utilizando materia fecal con formol con huevos de T. vulpis, los resultados fueron similares (Sheater: 61 vs sulfato de zinc: 0). Las cantidades de quistes de Giardia detectadas por formol-éter en materia fecal en fresco y con formol, fueron significativamente mayores que las detectadas por sulfato de zinc (87 y 19 vs 36 y 3, respectivamente). En 180 muestras examinadas la cantidad de detecciones de quistes Giardia sp efectuadas por medio de formol-éter fue significativamente mayor que por Sheater (15 vs 1, respectivamente). La técnica de Sheater fue más eficiente que la de sulfato de zinc en la detección de huevos de nematodes y la de formol-éter más eficiente para la detección de quistes de Giardia sp. De acuerdo a los resultados obtenidos se recomienda que, salvo indicaciones especiales cada muestra que requiera examen parasitológico sea procesada por las técnicas de Sheater y de formol-éter

Serum samples from 100 cats from La Plata and surroundings were studied to determine the relation between FIV infection and Toxoplasma gondii infection. Serum samples were analized to determine anti-FIV and anti-T. gondii antibodies, using immunoblotting test and immunofluorescence test, respectively. To analize the results, serum samples were classified into 4 groups according to the presence or not of anti-FIV and anti-T. gondii antibodies (Tox): Group 1) FIV+; Tox+ Group 2) FIV+ Tox-; Group 3) FIV- Tox+; Group 4) FIV- Tox-. Each group was further divided into 3 categories according clinical signs. The percentage of sera positive for FIV and T. gondii (34.5%, 19/55) was significantly higher than the percentage of sera positive for FIV and negative for T. gondii (17.7%, 8/45; p < 0.05, Fisher exact test). Antibodies tires anti-T. gondii were significantly higher in group 1 than in group 3. Distribution of clinical signs demonstrated significant differences between groups. The percentage of animals with clinical signs consistent with FIV and/or. T. gondii infections were as follows: Group 1: 57.9%; Group 2; 75%, Group 3: 48.6% and Graup 4: 27%. Results the present study indicate the association between FIV infection and T. gondii infection

Se Utilizaron 100 sueros de gatos provenientes de la ciudad de La Plata y alrededores con el fin de determinar la relación entre la infección con FIV y la infección con T. gondii. Los sueros se analizaron para determinar anticuerpos anti-FIV y anti-T.gondii por las pruebas de <<inmunobloting>> e inmunofluorescencia indirecta, respectivamente. Para el análisis de los resultados los sueros se clasificaron en cuatro grupos según presentaran o no anticuerpos anti-FIV y anti-T. gondii (Tox): Grupo 1) FIV+ Tox+; Grupo 2) FIV+ Tox-; Grupo 3) FIV- Tox+; Grupo 4) FIV- Tox-. Se establecieron tres categorías por grupo con respecto a los signos clínicos de los gatos estudiados. El por- centaje de sueros positivas a FIV y a T. gondii (34,5%, 19,) fue significativamente mayor que el porcentaje de sueros positivos a FIV y nagativos a T. gondii (17,7%, 8/45; p < 0,05, prueba exacta de Fisher). Los títulos de anticuerpos anti-T. gondii fueron siqnificativamente mayores en el Grupo 1 con respecto al Grupo 3. La distribución de los signos clínicos fue significativamente diferente entre los 4 grupos. El porcentaje de animales con signos clínicos potencialmente compatibles con FIV y/o toxoplasmosis fue: Grupo 1: 57,9%, , Grupo 2: 75%; Grupo 3: 48,6% y Grupo 4: 27%. Los resultados del presente trabajo indican la asociación entre la infección con el FIV y la infección con T.gondii