The purpose of this paper is to show the epistemological assumptions (empiricists, rationalists and ratioempirist) and ontological (individualistic, holistic and systemist) present in the history of ecology, analyzing three jobs (Clements 1916; Gleason 1926; Lindeman 1942). This article analyzes the emergence in the history of the ecology of a moderate position. We defend the thesis that from the work developed by Lindeman in 1942 began to emerge in ecology a conceptual framework that implicitly takes a systemist ontological and racioempirista epistemological approach, and fits into the philosophical principles developed by Bunge. We also show the disadvantages of implementing the rationalist and empiricist epistemology in ecological research, and the advantages of using the ratioempiricism epistemology. Currently, research programs in ecology follow one of three ontological and epistemological principles.

El propósito de este trabajo es mostrar los supuestos epistemológicos (empirista, racionalista y racioempirista) y ontológicos (individualista, holista y sistemista) presentes en la historia de la ecología, sobre la base de tres trabajos: Clements (1916), Gleason (1926) y Lindeman (1942). En este artículo analizamos el surgimiento de una posición moderada en la historia de la ecología. Defendemos la tesis de que a partir del trabajo publicado por Lindeman en 1942, comenzó a surgir en ecología un marco conceptual que toma implícitamente un enfoque ontológico sistemista y epistemológico racioempirista, y que se encuadra en los principios filosóficos desarrollados por Bunge. También mostramos las desventajas de implementar la epistemología racionalista y la epistemología empirista en la investigación ecológica, y las ventajas de utilizar la epistemología racioempirista. En la actualidad, los programas de investigación en ecología siguen alguno de estos tres principios ontológicos y epistemológicos.

Studies of carnivore diets provide essential information on ecosystem dynamics. The Pampas fox (Lycalopex gymnocercus) is an opportunistic carnivore. From the analysis of stomach content of 70 foxes we described the diet of L. gymnocercus and compared males and females in two rural areas in Buenos Aires Province, one characterized by Espinal habitat (Villarino) and the other by Pampas grassland (Azul). Diet was described using the following indices: relative frequency, frequency of occurrence, biomass contribution and relative abundance. Sexes and locations were compared with indices of diversity and dietary overlap. Our results support the hypothesis of an opportunistic diet where murine rodents were the most frequent item, while the main biomass contribution corresponded to caviomorphs, lagomorphs and carrion. These results suggest that L. gymnocercus is well adapted to rural areas with high levels of disturbance. We recorded a high dietary overlap between males and females without significant differences in prey diversity. Finally, a greater dietary diversity was observed in the Espinal, but dietary overlap was high among foxes from both regions, suggesting incipient homogenization between ecoregions due to increased human activities in these environments.

Los estudios de dieta sobre carnívoros aportan información indispensable para conocer la dinámica de un ecosistema. El zorro gris pampeano (Lycalopex gymnocercus) es un carnívoro oportunista. A partir del análisis de contenidos estomacales describimos la dieta de L. gymnocercus y analizamos diferencias entre machos y hembras en dos áreas rurales del sur de la provincia de Buenos Aires (Villarino [ecorregión Espinal] y Azul [ecorregión Pampeana]). Se recolectaron y analizaron 70 estómagos. La composición dietaria se estimó a partir de los siguientes índices: frecuencia relativa, frecuencia de ocurrencia, aporte de biomasa y abundancia relativa. Las comparaciones entre sexos y localidades se realizaron en base a índices de diversidad y de solapamiento dietario. Los resultados obtenidos apoyan la hipótesis de una dieta oportunista donde los roedores múridos fueron los ítems más frecuentes, mientras que el mayor aporte de biomasa correspondió a caviomorfos, lagomorfos y carroña. Estos resultados sugieren una adaptación de L. gymnocercus a ambientes rurales con altos niveles de perturbación; allí las especies más abundantes fueron, en general, las más consumidas. Entre machos y hembras se registró un elevado solapamiento dietario sin diferencias significativas para la diversidad entre ellos. Finalmente, al realizar las comparaciones entre regiones se observó una mayor diversidad dietaria en el Espinal; sin embargo, fue registrado un gran solapamiento dietario entre zorros de ambas ecorregiones, lo que supondría una incipiente homogeneización entre ecorregiones como consecuencia del incremento de la actividad humana sobre estos ambientes.

Resumo O presente estudo relata a ocorrência de Ancylostoma (Ancylostoma) buckleyi (Le Roux and Biocca, 1957) (Nematoda: Ancylostomatidae) no intestino delgado do Graxaim do campo (Lycalopex gymnocercus) (Mammalia: Canidae). Essa raposa é o carnívoro nativo mais abundante no sul da América do Sul, onde habita nas pastagens, florestas abertas e áreas altamente modificadas pelas atividades pecuária extensiva e agrícola. Material de 80 raposas, em áreas rurais do sul da província de Buenos Aires, Argentina, foi examinado. Os tratos intestinais foram cuidadosamente removidos de cada carcaça e, posteriormente, isolados por ligaduras (piloro e reto). O exame do conteúdo intestinal foi realizado, utilizando-se a técnica de sedimentação e contagem. Quatro raposas (5%) foram encontradas parasitadas com espécimes adultos de A. buckleyi. O estudo registra, pela primeira vez, a ocorrência de Ancylostoma (A.) buckleyi na Argentina e adiciona L. gymnocercus como novo hospedeiro dessa espécie de nematoides.

Abstract Here we report the occurrence of Ancylostoma (Ancylostoma) buckleyi (Le Roux and Biocca, 1957) (Nematoda: Ancylostomatidae) in the small intestine of Pampas foxes (Lycalopex gymnocercus) (Mammalia: Canidae). This fox is the most abundant native carnivore in southern South America, where it inhabits grasslands, open woodlands and areas highly modified by extensive ranching and agricultural activities. Material from 80 foxes in rural areas of southern Buenos Aires province, Argentina was examined. The intestinal tracts were carefully removed from each carcass and subsequently isolated by ligatures (pylorus and rectum). Examination of the intestinal content was performed using the sedimentation and counting technique. Four foxes (5%) were found to be parasitized with adult specimens of A. buckleyi. This is the first report of Ancylostoma (A.) buckleyi in Argentina and adds L. gymnocercus as new host of this nematode species.

Cultural practices, apart from affecting soil nutrient availability, have an important impact on the nematode population. In the present study, soil nematodes in vegetables and fruits from the horticultural belt extending from Sierra de los Padres to Batan city were analyzed. Free-living nematodes presented an overall frequency of 20.78% on vegetable samples. Four trophic groups were identified: bacteriophages 89.81%, fungivorous 5.55%, omnivores 3.7% and carnivores 0.92%; eight families and 12 genera of nematodes were also identified. The bacteriophage group was the richest with nine genera. The studied farms used to incorporate organic nitrogen through chicken feces and/or inorganic nitrogen through urea. The total abundance of nematodes during the sampling period was higher in spring. The Panagrolaimidae and Rhabditidae families were present in the four seasons. The first family presented elevated frequencies in spring while both of them were highly frequent in winter. This study highlights the potential of vegetables as vehicles for obtaining edaphic nematodes, which are useful as cultivated soils ecological indicators. The present case showed that the bacteriophage group presented the largest frequency and diversity in cultured soils of the Gral. Pueyrredon horticultural belt.

Se ha demostrado que las prácticas de cultivo, además de alterar la disponibilidad de nutrientes del suelo, tienen una importante acción sobre la población de nematodos. En el presente estudio se analizó la fauna de nematodos de suelo en verduras y frutas provenientes del cinturón fruti-hortícola que se extiende desde la zona de Sierra de los Padres hasta la ciudad de Batán, en el partido de General Pueyrredon, provincia de Buenos Aires. El 20,78% de las muestras vegetales presentó nematodos de vida libre. Se identificaron cuatro grupos tróficos: bacteriófagos 89,81%, fungívoros 5,55%, omnívoros 3,7% y carnívoros 0,92%; ocho familias y 12 géneros de nematodos, observándose una mayor riqueza en el grupo de bacteriófagos con nueve géneros. En las quintas muestreadas se solía incorporar a los sistemas de producción nitrógeno como abono orgánico a través de heces de gallina y/o abono inorgánico a través de urea. La abundancia total de nematodos en el período de muestreo fue mayor en primavera. Las familias Panagrolaimidae y Rhabditidae estuvieron presentes en las cuatro estaciones, siendo Panagrolaimidae la más frecuente en primavera en tanto que en invierno ambas familias mostraron elevadas frecuencias. Los resultados de este trabajo nos permiten considerar a las verduras como un vehículo interesante para la obtención de nematodos edáficos, los cuales sirven como indicadores ecológicos de los suelos cultivados. En el presente caso se evidenció a los nematodos bacteriófagos como los más frecuentes y diversos en los sistemas de producción fruti-hortícola del partido de Gral. Pueyrredon.

Os cães são hospedeiros definitivos de vários helmintos e protozoários zoonóticos. As áreas rurais do distrito de Lobos, no nordeste da província de Buenos Aires, Argentina, destinam-se principalmente à atividade pecuária aumentando desta forma o número de cães em fazendas, bem como o risco humano de infecções parasitárias. Os objetivos desta pesquisa foram avaliar as infecções endoparasitas em cães de fazendas do distrito de Lobos e analisar a sua importância zoonótica, bem como as práticas de risco e hábitos da população rural. Quarenta e duas amostras de fezes de cães obtidos em 21 fazendas foram analisadas pelos métodos coproparasitológicos e testes de coproantígenos, resultando numa prevalência de parasitas de 69,05% e 80,95% das propriedades parasitados. Os parasitas mais frequentes foram Trichuris vulpis e Eucoleus aerophila(26,19%), Echinococcus granulosus(19,05%), Uncinaria stenocephala e coccídeos (14,29%). A análise dos arquivos epidemiológicos mostraram vários hábitos da população rural como fatores de risco associados com a presença de amostras fecais parasitadas e a presença de E. granulosus em propriedades rurais. É evidente que as pessoas das fazendas estudadas foram expostas a vários helmintos que podem causar doenças graves como equinococose cística, que constitui importante problema de saúde pública e econômico a nível mundial.

Dogs are definite hosts for several zoonotic helminthes and protozoan. Rural areas from the Lobos District in the northeast of Buenos Aires province, Argentina, are mainly used for livestock activity, increasing in this way the number of dogs on farms as well as the human risk of parasitic infections. The aims of this research were to evaluate the endoparasitic infections in dogs from farms in the Lobos District and analyze their zoonotic importance as well as several risk practices and habits of the rural population. Forty-two dog fecal samples obtained in 21 farms were analyzed through coproparasitological methods and coproantigen tests, which resulted in an overall parasite prevalence of 69.05% and 80.95% of the parasitized farms. The most frequent parasites were Trichuris vulpis and Eucoleus aerophila (26.19%), Echinococcus granulosus (19.05%), Uncinaria stenocephala and coccids (14.29%). The analysis of epidemiological files showed several habits of the rural population considered as risk factors associated with the presence of fecal samples parasitized and the presence of E. granulosus on the farms. It is clear that people involved with the farms studied were exposed to several helminthes that could cause serious diseases like cystic echinococcosis, which can become an important public health issue and affect the economy worldwide.

Discriminant analysis was used to identify eggs of Capillaria spp. at specific level found in organic remains from an archaeological site in Patagonia, Argentina, dated of 6,540 ± 110 years before present. In order to distinguish eggshell morphology 149 eggs were measured and grouped into four arbitrary subsets. The analysis used on egg width and length discriminated them into different morphotypes (Wilks' lambda = 0.381, p < 0.05). The correlation analysis suggests that width was the most important variable to discriminate among the Capillaria spp. egg morphotypes (Pearson coefficient = 0.950, p < 0.05). The study of eggshell patterns, the relative frequency in the sample, and the morphometric data allowed us to correlate the four morphotypes with Capillaria species.

A hidatidose é uma zoonose de distribuição mundial produzida principalmente pela meta-cestódeo Echinococcus granulosus. Na Argentina, a distribuição alcança níveis endêmicos. O objetivo desta pesquisa foi contribuir ao conhecimento da hidatidose no sudeste da província de Buenos Aires, estudar sua evolução no Hospital Geral Interzonal para Doenças Infecciosas Agudas, entre 1992 e 2002 e discutir sua importância. Os registros clínicos dos pacientes operados e/ou diagnosticados foram revisados quanto a esta doença. Cento e vinte casos foram analisados. Entre os pacientes, 56,7% eram mulheres. A idade média foi de 42,2+16,8 anos. Um grupo de 68,3% eram residentes urbanos. Em 75% dos casos, foi utilizada a ultrassonografia. Observou-se mais freqüentemente a localização hepática. Um grupo de 89,2% foi submetido a tratamento cirúrgico. Utilizou-se albendazole em 19 pacientes. A duração média da hospitalização foi de 16 dias. Concluímos que esta zoonose é uma doença que gera custos altos na atenção médica e, por isso, mais estudos epidemiológicos devem ser feitos e as autoridades públicas de saúde devem implementar estratégias de controle e prevenção na região.

Hydatidosis is a zoonosis of worldwide distribution produced mainly by the metacestode Echinococcus granulosus. In Argentina, its distribution reaches endemic levels. The aims of this investigation were to contribute to the knowledge of hydatidosis in the southeast of Buenos Aires province, study its evolution at the Interzonal General Hospital for Acute Diseases between 1992 and 2002 and discuss its importance. Clinical records of operated and/or diagnosed patients were reviewed with regard to this disease. One hundred and twenty cases were analyzed. Among the patients, 56.7% were women. The average age was 42.2+16.8 years. 68.3% lived in urban areas. In 75% of the cases, ultrasonography was used. Hepatic location was most frequently seen. 89.2% received surgical treatment. Albendazole was used for 19 patients. The mean length of hospital stay was 16 days. We conclude that this zoonosis is a disease that generates high costs in medical care and for this reason more epidemiological studies should be carried out and public health authorities should implement control and prevention strategies in the region.

Introduction. Canine population in Mar del Plata city, Argentina, is over 100.000 dogs. This situation produces a great number of canine feces in the environment with the dangerous consequences on human health, increasing the probability of infection with zoonotic parasites from public places where dogs and humans co-ocurr. The aim of the present research was to study the parasite condition of samples of canine feces collected from public squares of Mar del Plata city and from the Municipal Center of Zoonosis, in order to know the sanitary risk of the public environments of the city. Material and methods. From September 2001 to March 2002, 205 dogs from the Municipal Center of Zoonosis and 288 samples of feces from 21 squares of Mar del Plata city were examined for zoonotic parasites. Samples were processed by Willis floating-sedimentation technique. Total prevalence by parasite species and percentage of mono and poliparasitized samples were calculated. Samples were statistically compared by <img border=0 width=16 height=19 src="/img/revistas/aap/v102n5/a03form1.gif" align=texttop>test. Results. Parasites identified from squares were uncinariae, Trichuris vulpis, Toxocara canis, coccidia and Amoeba spp. From the Municipal Center of Zoonosis (CMZ), in addition to the above mentioned parasites, Capillaria aerophila and Dipylidium caninum were also found. Total prevalence of parasites and percentage of poliparasitized samples were significantly higher in the Municipal Center of Zoonosis than in public squares. Conclusion. The results showed evidence of a high prevalence of canine enteroparasites of zoonotic relevance on human and veterinary health in dogs inhabiting public places of the city. Education campaigns directed to public health care and to increase the responsibility of people on pets are needed.

Introducción. La ciudad de Mar del Plata presenta una población estimada de 100.000 canes. Esta situación genera alta contaminación del ambiente con materia fecal canina, incrementando la probabilidad de infección por parásitos zoonóticos para las personas y perros que concurren a los espacios públicos. El objetivo del presente trabajo fue analizar conjuntamente los resultados obtenidos a partir del análisis de materia fecal canina procedente de plazas públicas y del Centro Municipal de Zoonosis, para dimensionar el riesgo sanitario existente en el ambiente. Material y métodos. Entre septiembre de 2001 y marzo de 2002 se examinaron coproparasitológicamente 205 perros ingresados al Centro Municipal de Zoonosis y 288 muestras provenientes de 21 plazas de la ciudad. Las muestras se procesaron mediante la técnica de flotación-sedimentación de Willis. Se calcularon las prevalencias de parásitos totales, los porcentajes por especie y los porcentajes de muestras monoparasitadas y poliparasitadas. Los resultados se compararon aplicando la prueba de x². Resultados. Las especies identificadas en plazas fueron: uncinarias, Trichuris vulpis, Toxocara canis, coccidios y amebas. En el Centro Municipal de Zoonosis, además de éstas, se identificaron Capillaria aerophila y Dipylidium caninum. La prevalencia total de parásitos fue significativamente mayor en el Centro Municipal de Zoonosis y también lo fue el porcentaje de muestras poliparasitadas. Conclusiones. Los resultados de este estudio demuestran una alta prevalencia de enteroparásitos caninos de importancia en salud pública y veterinaria en los caninos de la ciudad, por lo que se hace necesario implementar campañas de salud pública para concientizar a la población y generar conductas de tenencia responsable de mascotas.

In Mar del Plata city, Buenos Aires province (Argentina), a sampling of canine faeces was made at 11 public squares with the aim to identify zoonotic parasite species from dogs. Squares were classified into two groups: Central and Peripheric. Samples were taken at square flowerbeds (90.4%), special cages for dogs (6.4%) and child´s games areas (3.2%). All the squares were found contaminated with faeces and 100% of them were positive for parasites. Total prevalence was 49.95%; prevalence by parasite species was 62.96% for Ancylostoma caninum and Trichuris vulpis, 24.07% for Uncinaria stenocephala, 22.22% for Toxocara canis, 9.25% for Amoeba spp., 3.70% for coccidians and 1.85% for Pseudophyllideans. Percentage of parasitized samples was higher at peripheric squares than at the central group. Parasite prevalences at each square group were compared with results registered in different areas of Argentina. Results obtained in the present study, as related with canine faeces disseminated along public places and the sanitary consequences to the human health, are discussed

En la ciudad de Mar del Plata, provincia de Buenos Aires (Argentina) se realizó un muestreo de 11 plazas públicas, con el propósito de identificar las especies de parásitos presentes en la materia fecal canina, en especial aquellos de importancia zoonótica. Las plazas fueron clasificadas en céntricas y periféricas. Se extrajeron muestras en canteros (90,4%), caniles (6,4%) y lugares de juegos (3,2%) de cada una de las plazas y se efectuó el análisis coproparasitológico. Todas las plazas presentaron contaminación con materia fecal y el 100% resultó positivo a la presencia de parásitos. La prevalencia total de parásitos para el conjunto de plazas fue del 49,95% y las prevalencias por especie de parásito fueron: Ancylostoma caninum y Trichuris vulpis (62,96%), Uncinaria stenocephala (24,07%), Toxocara canis (22,22%), Amoeba spp. (9,25%), coccidios (3,70%) y Pseudophyllideos (1,85%). El porcentaje de muestras parasitadas fue mayor en las plazas de la periferia que en el grupo del centro. Las prevalencias registradas en cada uno de los grupos de plazas se compararon con las calculadas en otras áreas geográficas de la República Argentina

To assess the health risk associated with Echinococcus granulosus, a retrospective survey of hydatid infection was conducted between 1992 and 1995 by examining records of patients with hydatidosis from two hospitals of Mar del Plata City, General Pueyrredón District, Buenos Aires Province, Argentina.Eighty five patients (34 males and 51 females) with confirm hydatidosis were registered. The average age was 48.2 years. Employee was the occupation that present the greatest percentage of cases (16.5%). Ultrasonography (US) was the most frequently used diagnostic method (28.2%). Infection in the liver occurred most commonly (58.8% of the 85 cases). Of the 85 patients, 74 (87.1%) received surgery; 12 received medical treatment with albendazole.The results obtained in this work from two hospitals show a problematic situation with respect to hydatid disease in Mar del Plata City. To have a good view of infection prevalence in Mar del Plata City, more retrospective survey data on human hydatidosis must be don

The presence of Bertiella mucronata and Bertiella studeri (Cestoda: Anoplocephalidae) in humans is reviewed, and international infection rates and a bibliography included. Taxonomic, biological, epidemiological, pathological, diagnostic, control, prevention and therapeutic aspects of the zoonosis are analyzed, and the increase in zoonotic potentiality of the parasitosis is discussed

Bertielliosis en el hombre: revisión de casos En este trabajo se hace una revisión de los casos humanos parasitados por Bertiella mucronata y Bertiella studeri (Cestoda: Anoplocephalidae), que incluye la casuística internacional y bibliografia actualizada. Se analizan varios aspectos de esta zoonosis como son: taxonomia, ciclo biológico, epidemiología, patologia, diagnóstico, control, prevención y terapéutica. Se discuten aspectos relacionados con la potencialidad zoonótica creciente de esta parasitosis