Could beta-myrcene be an alternative to albendazole for the treatment of experimental cystic echinococcosis?

Echinococcus granulosus causes hydatidosis or cystic echinococcosis in humans and livestock. In humans, this disease can be managed with surgery, percutaneous treatment, chemotherapy and/or observation. The chemotherapeutic agents used and approved for treatment of hydatidosis are benzimidazoles. Because of the difficulties in achieving successful treatment, considerable efforts have been made to find new natural compounds against hydatid disease. Beta-myrcene is a monoterpene presented in the essential oils of different plants. It is the principal component of essential oil of Rosmarinus officinalis (rosemary). The goal of the present study was to evaluate the in vitro effects of beta-myrcene against germinal cells, protoscoleces and murine cyst of E. granulosus, as well also, investigate its chemoprophylactic activity in a murine model of cystic echinococcosis. For the in vitro assays, the parasites were incubated with beta-myrcene at 10, 5 and 1 µg/mL. The treatments were dose and time-dependent, and consistent with the observed morphological alterations. In the chemoprophylactic efficacy study, the effect of beta-myrcene was similar to albendazole, the reference drug for human echinococcosis treatment.

Chemoprophylactic and therapeutic efficacy of thymol in murine cystic echinococcosis.

Cystic echinococcosis is a zoonotic disease caused by the larval stage of the cestode Echinococcus granulosus. The drugs commonly used against cystic echinococcosis are benzimidazoles. Unfortunately, 20%-40% of cases do not respond favorably to such chemotherapy. Consequently, the search of new therapeutic alternatives such as the use of traditional medicinal plants has been increased. The aim of the current experimental work was to investigate the chemoprophylactic and clinical efficacy of thymol on mice infected with E. granulosus metacestodes. Thymol (40 mg/kg) was administered under two different therapeutic schemes: dosing every 24h over 20 days and treatment every 12h for 10 days. Thymol demonstrated efficacy against experimental murine cystic echinococcosis. The chemoprophylactic and therapeutic effects of thymol were comparable to that of albendazole. Due to the lack of toxicity observed in mice at the tested doses; we consider that thymol is a potential alternative to be applied for the treatment of human hydatid disease.

A pharmacology-based comparison of the activity of albendazole and flubendazole against Echinococcus granulosus metacestode in sheep.

Cyst echinococcosis (CE) is a zoonotic disease caused by the larval stage of the Echinococcus granulosus helminth parasite. The work reported here aimed to compare the efficacy of albendazole (ABZ) and flubendazole (FLBZ) against CE in naturally infected sheep. Additionally, their comparative pharmacokinetic behaviour and the assessment of serum liver enzymes activities were studied. Twelve (12) naturally infected sheep were allocated to the following experimental groups: unmedicated control group, FLBZ-treated and ABZ-treated. Treatments were orally performed every 48 h, over 55 days at dose rate of 10 (FLBZ) and 8.5 (ABZ) mg/kg (equimolar dose rates). The efficacy of the drug treatments was based on protoscoleces' vitality/viability. The kinetic disposition assessment included the Initial and Final Kinetic Studies which implicated the collection of blood samples after both the first and the last drug administration. Blood samples were processed to measure drug concentrations by HPLC. The protoscoleces' vitality observed in the untreated control group (98%) was significantly reduced in the presence of both ABZ and FLBZ. 90% of mice inoculated with protoscoleces in the control group developed hydatid cysts in their peritoneal cavity (viability study). However, only 25% (FLBZ) and 33% (ABZ) of mice inoculated with protoscoleces recovered from treated sheep, developed hydatid cysts in their abdominal cavity. Reduced FLBZ (R-FLBZ) was the main metabolite recovered in the bloodstream after oral administration of FLBZ to sheep. Low plasma concentrations of FLBZ parent drug were measured up to 48 h post-administration. ABZ was not detected in plasma at any time post-treatment, being its metabolites ABZ sulphoxide (ABZSO) and ABZ sulphone (ABZSO2) recovered in plasma. Hepatotoxicity due to the continued treatment with either ABZ or FLBZ was not observed. A 3-fold increase ethoxyresorufin O-deethylase activity, a cytochrome P450 1A (CYP1A)-dependent enzyme reaction, was observed in liver microsomes obtained from sheep receiving ABZ, compared to those of the unmedicated and FLBZ-treated animals. In conclusion, FLBZ is an available anthelmintic which may be developed into an effective and safe drug for the human CE treatment. Despite the low plasma concentrations measured by FLBZ/R-FLBZ, an important reduction in protoscoleces' vitality was observed in cysts located in sheep liver. Modern pharmaceutical technology may help to greatly improve FLBZ systemic exposure improving its efficacy against CE.

Echinococcus granulosus: biological comparison of cattle isolates from endemic regions of Argentina and Spain / Echinococcus granulosus: comparación biológica de aislados de bovinos de regiones endémicas de Argentina y España

In the present study we have compared cattle isolates of Echinococcus granulosus from Argentina and Spain. The aim was to compare and determine if there exist phenotypic and genetic differences within E. granulosus cattle isolates between an endemic area of Spain (where the disease is mainly restricted to a sheep-dog cycle) and an endemic area of Argentina (where cattle are the most abundant intermediate hosts). The Spanish samples were previously identified as G1 genotype. The Argentinean samples were also identified as G1, but some variants were found for the cytochrome c oxidase-1 (CO1) and NADH dehydrogenase-1 (ND1) mitochondrial genes. When comparing the cyst features and the morphology of the larval rostellar hooks in both regions, some differences were found. The morphometric analyses of the larval rostellar hooks showed the existence of two distinct clearly separated groups (one corresponding to the Argentinean samples and the other to the Spanish ones). In conclusion, there are some genetic and phenotypic differences within E. granulosus cattle isolates from Argentina and Spain. Probably these differences, more important from an epidemiological point of view, are related to different steps in the disease control in both countries. Further studies involving other epidemiological, morphometric and molecular data, including other types of livestock, would contribute to clarify and expand the present work.

El objetivo del presente trabajo fue determinar si existen diferencias fenotípicas y genéticas entre los aislados de Echinococcus granulosus de origen bovino provenientes de dos regiones geográficas donde la hidatidosis es endémica, una de España (donde predomina el ciclo perro-oveja) y una de Argentina (donde el bovino es el hospedador intermediario más importante). Las muestras españolas fueron previamente identificadas como pertenecientes al genotipo G1. Las muestras argentinas también correspondían al genotipo G1, pero entre ellas se registraron algunas microvariantes de los genes mitocondriales citocromo c oxidasa-1 (CO1) y NADH deshidrogenasa- 1 (ND1). La comparación de las características de los quistes y de la morfología de los ganchos rostelares del metacestode mostró ciertas diferencias. En conclusión, existen algunas diferencias genéticas y fenotípicas entre los aislados de E. granulosus de Argentina y España. Probablemente estas diferencias, más importantes desde el punto de vista epidemiológico, podrían estar relacionadas con diferentes etapas en los programas de control de la enfermedad en los dos países. Estudios adicionales que involucren datos epidemiológicos, morfométricos y moleculares provenientes de otros tipos de ganado contribuirán a clarificar y ampliar la información aportada por este trabajo.

Pediatric hydatidosis in the south-east of the Buenos Aires province, Argentina.

Hydatidosis is a zoonosis produced by the metacestode Echinococcus spp. The aims of this research are: to contribute to the knowledge of pediatric hydatidosis in the south-east of Buenos Aires province, to study its evolution from 1993 to 2002 at the Regional Maternity and Pediatric Hospital "Dr. Victorio Tetamanti", to determine the strains involved and to discuss the importance of the disease. The clinical records of diagnosed and/or operated patients were reviewed with regard to the hydatid disease. The strain was determined by using PCRs with Eg1 121a/122a primers. Forty-four cases were analyzed. Fifty nine point one per cent of the patients were boys. The mean age was 8 SD=3.8 years. Sixty one point four per cent had urban residence. Ultrasonography was used in 61% of the cases. The hepatic location was most frequently seen and the liver/lung ratio was 1.25. Ninety point nine per cent of patients received surgical treatment. Albendazole was used in 52% of cases. The average hospitalization time was 11 days. The G1/G2 strain group was determined. This report is the first one of its kind in the studied region. The permanence of hydatidosis in the region depends on the natural transmission of the parasite in the absence of control and prevention measures. The health authorities should implement strategies of prevention and control in the study area.

Pediatric hydatidosis in the south-east of the Buenos Aires province, Argentina / Hidatidosis pediátrica en el sudeste de la provincia de Buenos Aires, Argentina

Hydatidosis is a zoonosis produced by the metacestode Echinococcus spp. The aims of this research are: to contribute to the knowledge of pediatric hydatidosis in the south-east of Buenos Aires province, to study its evolution from 1993 to 2002 at the Regional Maternity and Pediatric Hospital "Dr. Victorio Tetamanti", to determine the strains involved and to discuss the importance of the disease. The clinical records of diagnosed and/or operated patients were reviewed with regard to the hydatid disease. The strain was determined by using PCRs with Eg1 121a/122a primers. Forty-four cases were analyzed. Fifty nine point one per cent of the patients were boys. The mean age was 8 SD=3.8 years. Sixty one point four per cent had urban residence. Ultrasonography was used in 61% of the cases. The hepatic location was most frequently seen and the liver/lung ratio was 1.25. Ninety point nine per cent of patients received surgical treatment. Albendazole was used in 52% of cases. The average hospitalization time was 11 days. The Gl/G2 strain group was determined. This report is the first one of its kind in the studied region. The permanence of hydatidosis in the region depends on the natural transmission of the parasite in the absence of control and prevention measures. The health authorities should implement strategies of prevention and control in the study area.

Los objetivos de este trabajo fueron: contribuir al conocimiento de la hidatidosis pediátrica en el sudeste de la provincia de Buenos Aires, estudiar su evolución desde 1993 hasta 2002, establecer la o las cepas involucradas y discutir la importancia de la enfermedad. Para ello se revisaron las historias clínicas de los pacientes pediátricos con diagnóstico de hidatidosis asistidos en el Hospital Interzonal Especializado Materno Infantil "Dr. Victorio Tetamanti" durante ese período. Se analizaron 44 casos, el 59,1% de ellos correspondió a varones. La media de edad fue de 8 años (SD=3,8 años) y el 61,4% de los niños afectados eran de residencia urbana. Se empleó ultrasonografía como método diagnóstico en el 61% de los casos. La localización hepática fue la más frecuente y la relación hígado/pulmón fue 1,25. El 90,9% recibió tratamiento quirúrgico. Se utilizó albendazol en el 52% de los pacientes. El tiempo de hospitalización tuvo una mediana de 11 días. Las cepas se determinaron mediante PCR con los cebadores Eg1 121a/122a. Se determinó la presencia de cepas del grupo G1/G2, dato informado por primera vez en humanos para la región de estudio. Se concluyó que la permanencia de la enfermedad en la región depende de la transmisión natural del parásito en ausencia de medidas de control y prevención. Por consiguiente, las autoridades de salud deberían implementar estrategias de prevención y control en dicha zona.

Flubendazole and ivermectin in vitro combination therapy produces a marked effect on Echinococcus granulosus protoscoleces and metacestodes.

The aim of the present work was to evaluate the in vitro efficacy of the flubendazole (FLBZ) and ivermectin (IVM) combination against Echinococcus granulosus protoscoleces and metacestodes. Protoscoleces and groups of ten peritoneal cysts obtained from BALB/c mice were incubated with the two drugs, either separately or in combination, at the following final concentrations: 10 microg/mL FLBZ, 1 microg/mL FLBZ, 1 microg/mL IVM, 10 microg/mL FLBZ + 1 microg/mL IVM, and 1 microg/mL FLBZ + 1 microg/mL IVM. The maximum protoscolicidal effect was found with the combination 10 microg/mL FLBZ + 1 microg/mL IMV. After 1 day of incubation, the presence of numerous blebs in the tegument of protoscoleces was observed. Ultrastructural studies revealed that the primary site of damage was the tegument of the parasite. The effect of the two drugs on hydatid cysts obtained from mice was more rapidly detected in cysts treated with the combination of FLBZ + IVM than when drugs were used separately. Ultrastructural studies revealed that the germinal layer of treated cysts lost the multicellular structure feature and underwent considerable degenerative changes after in vitro treatment. The outcomes obtained demonstrated the favorable effect of the combination of FLBZ and IVM against E. granulosus.

A novel phylogeny for the genus Echinococcus, based on nuclear data, challenges relationships based on mitochondrial evidence.

The taxonomic status of Echinococcus, an important zoonotic cestode genus, has remained controversial, despite numerous attempts to revise it. Although mitochondrial DNA (mtDNA) has been the source of markers of choice for reconstructing the phylogeny of the genus, results derived from mtDNA have led to significant inconsistencies with earlier species classifications based on phenotypic analysis. Here, we used nuclear DNA markers to test the phylogenic relationships of members of the genus Echinococcus. The analysis of sequence data for 5 nuclear genes revealed a significantly different phylogeny for Echinococcus from that proposed on the basis of mitochondrial DNA sequence data, but was in agreement with earlier species classifications. The most notable results from the nuclear phylogeny were (1) E. multilocularis was placed as basal taxon, (2) all genotypes of Echinococcus granulosus grouped as a monophyletic entity, and (3) genotypes G8 and G10 clustered together. We conclude that the analysis of nuclear DNA data provides a more reliable means of inferring phylogenetic relationships within Echinococcus than mtDNA and suggest that mtDNA should not be used as the sole source of markers in future studies where the goal is to reconstruct a phylogeny that does not only reflect a maternal lineage, but aims to describe the evolutionary history at species level or higher.

Echinococcus granulosus: biological comparison of cattle isolates from endemic regions of Argentina and Spain.

In the present study we have compared cattle isolates of Echinococcus granulosus from Argentina and Spain. The aim was to compare and determine if there exist phenotypic and genetic differences within E. granulosus cattle isolates between an endemic area of Spain (where the disease is mainly restricted to a sheep-dog cycle) and an endemic area of Argentina (where cattle are the most abundant intermediate hosts). The Spanish samples were previously identified as G1 genotype. The Argentinean samples were also identified as G1, but some variants were found for the cytochrome c oxidase-1 (CO1) and NADH dehydrogenase-1 (ND1) mitochondrial genes. When comparing the cyst features and the morphology of the larval rostellar hooks in both regions, some differences were found. The morphometric analyses of the larval rostellar hooks showed the existence of two distinct clearly separated groups (one corresponding to the Argentinean samples and the other to the Spanish ones). In conclusion, there are some genetic and phenotypic differences within E. granulosus cattle isolates from Argentina and Spain. Probably these differences, more important from an epidemiological point of view, are related to different steps in the disease control in both countries. Further studies involving other epidemiological, morphometric and molecular data, including other types of livestock, would contribute to clarify and expand the present work.

Enteroparasitosis y estado nutricional en niños menores de 4 años de wawa-wasi de Pamplona Alta San Juan de Miraflores Lima - Perú - 2006 / Enteroparasities and nutritional status in children younger than 4 years old from daycare centers of pamplona Alta San Juan de Miraflores, Lima, Peru, 2006

Se realizó un estudio prospectivo transversal de 112 niños entre 1 a 4 años de tres wawa wasi del área de Pamplona Alta en el distrito de San Juan de Miraflores con la finalidad de estudiar la prevalencia de enteroparasitosis y su relación con el estado nutricional. Para determinar la prevalencia de parasitosis intestinal se utilizó la Técnica de Burrows (PAF), para el diagnóstico de Enterobius vermicularis se utilizaron el método de la cinta engomada o Test de Grahan. Para determinar el estado nutricional se clasificó a los participantes en 4 categorías según el indice de Waterlow: eutrófico, desnutrido agudo, desnutrido crónico compensado y desnutrido crónico reagudizado, se emplearon los indicadores Antropométricos: peso/edad, talla/edad, peso/talla, para lo cual se utilizaron tablas antropométricas de la National Center for Health Stadistics del 2004. En cuanto a la prevalencia de parasitosis fueron positivas en el 82 por ciento de la población 18 por ciento de las muestras resultaron negativas. Se encontró que Enterobirus vermicularis fue el parásito más frecuente con 66 por ciento de los casos, seguido por Giardia Lamblia 17 por ciento. Se encontró que el 55 por ciento de la población fueron eutróficos, 7 por ciento desnutridos agudos y 38 por ciento desnutridos crónicos compensados. De los niños eutróficos el 73 por ciento estaban parasitados, mientras que el 91 por ciento de los 100 por ciento de los desnutridos agudos tenían parásitos. Con estos resultados nutricional y la frecuencia de enteroparasitosis en la población estudiada.

Prospective study of 112 children cross between 1 and 4 years of three wawa wasi Pamplona Alta area in the district of San Juan de Miraflores with the aim of studying the prevalence of enteroparasitosis and its relationship with the state nutritional. To determine the prevalence of intestinal parasitosis used the technique Burrows (PAF) for the diagnosis of Enterobius vermicularis is the method used tape or rubberized test Graham. To determine the nutritional status was classified the participants into 4 categories according to the index Waterlow: eutrófico, acute undernourished, underfed and malnourished chronic harmonious chronic reagudización, were used anthropometric indicators: weight/age, height/age, weight / height for which were used anthropometric tables of the National Center for Health Stadistics 2004. As for the prevalence of parasites were positive for 82 per cent of the population 18 per cent of samples were negative. It was that Enterobirus vermicularis was the most frequent parasitie with 66 per cent of cases, followed by Giardia lamblia 17 per cent. It was found that 55 per cent of the population were eutrophic, 7 per cent acute malnutrition amd 38 per cent chronically malnourished compensated. Of the children eutróficos 73 per cent were infected, while 91 per cent of chronically malnourished offset were infested, and 100 per cent of acute had parasities. We conclude that there is a strong link between nutritional status and frequency of enteroparasitosis in the population studied.

The scientific research programmes of Lakatos and applications in parasitology.

The methodology of scientific research programme (MSRP) proposed by Lakatos was in the line of the proposals made by Popper. MSRP were intended for constructing and evaluating research programme, which is unique among philosophers of science. Surprisingly, scientists dedicated to research in mathematics, physic or biology have not used much MRSP. This could be due to the fact that scientists are not aware of the existence of MSRP, or they find it difficult to apply to their own investigations. That is why we present firstly the main characteristics of this methodology (hard core--the group of hypothesis that are admitted by experts in the field, auxiliary hypotheses--which are intended to protect and refine the hypotheses of the hard-core, and heuristics for mending and evaluating the MSRP) and, secondly, propose an example in helminthology. We think that the methodology of Lakatos, is a useful tool, but it cannot encompass the large flexibility of investigations pathways.

Seasonal fluctuations in prevalence of dog intestinal parasites in public squares of Mar del Plata city, Argentina and its risk for humans / Estacionalidad en la prevalencia de parásitos intestinales caninos en plazas públicas de Mar del Plata, Argentina, y su riesgo para la salud humana

The aim of this work is to analyze whether there is a seasonal prevalence of parasites in dog feces from public squares in Mar del Plata city, Argentina, and to evaluate the climatic conditions that promote the development of parasites and allow the transmission to people. The study was performed in 21 squares from June 2001 to May 2002. Samples were processed by the Willis technique. Differences in prevalence of parasites were examined for significance by the Chisquare test. Climatic data were obtained from the Library of the National Meteorological Service of Argentina. Total parasitic prevalence was higher in winter than in summer. The prevalence of Ancylostoma spp. was higher in the summer-autumn period. For Toxocara canis, the prevalence was higher in winter whereas for Trichuris vulpis, it was higher in winter, spring and summer. This work shows high prevalence of total parasites throughout the year. For Ancylostoma spp., summer and autumn might be the seasons with higher sanitary risk. On the other hand, T. canis could present the higher risk to people in winter and, T. vulpis, would be transmitted throughout the whole year. The seasonal variation in prevalence of dog parasites results in continuous exposure to people visiting the squares, not only Mar del Plata residents but also tourists from other regions of Argentina and the world, with at least one species of parasite with sanitary risk.

El objetivo de este trabajo es analizar la variación estacional de la prevalencia de los parásitos presentes en las heces caninas halladas en plazas públicas de la ciudad de Mar del Plata y evaluar aquellas condiciones climáticas que promueven su desarrollo y permiten su transmisión a la gente. El estudio se realizó en 21 plazas desde junio de 2001 hasta mayo de 2002. Las muestras fueron procesadas con la técnica de Willis. Se utilizó el test de c² para comparar la prevalencia de los diferentes parásitos. Los datos climáticos fueron obtenidos en la biblioteca del Servicio Meteorológico Nacional. La prevalencia total de parásitos fue considerablemente más alta en invierno que en verano. Ancylostoma spp. fue la especie prevalente en el período otoño-verano. La incidencia de Toxocara canis fue más alta en invierno que en el resto de las estaciones, y la de Trichuris vulpis fue alta en invierno, primavera y verano. Este trabajo muestra alta prevalencia de parásitos totales a lo largo de todo el año en las plazas públicas de Mar del Plata. Para Ancylostoma spp. verano y otoño podrían ser las estaciones con riesgo sanitario más alto para la gente. Por otra parte, T. canis podría presentar mayor riesgo para la gente en invierno y T. vulpis sería transmitido durante todo el año. La variación estacional en la prevalencia de los distintos parásitos caninos, con al menos una especie con riesgo sanitario, hace que la exposición para la gente que visita las plazas sea continua e involucre no sólo a la gente que vive en Mar del Plata sino también turistas de otras regiones de Argentina y el mundo.

Paleoparasitological analysis of a raptor pellet from southern Patagonia.

Organic remains attributable to one regurgitated pellet were examined. The pellet, belonging to a bird of prey and collected from a cave of Southern Patagonia, was dated at 6,540 +/- 110 yr. With standard paleoparasitological procedures, eggs of Capillaria sp. and a mite, Demodex sp., were found. The parasites found in the pellet belong to a rodent ingested by the bird. The present report constitutes the first paleoparasitological study of a regurgitated pellet.

In vitro and in vivo effects of flubendazole on Echinococcus granulosus metacestodes.

The aim of the present work was to determine the efficacy of flubendazole (FLBZ) against Echinococcus granulosus metacestodes by using in vitro and in vivo models. Groups of 50 microcysts developed in vitro, and groups of 10 peritoneal cysts were obtained from Balb C mice with experimental secondary infections of 8 months. The cysts were placed in Leighton tubes containing 10 ml of culture medium. FLBZ was added to the medium resulting in final concentrations of 5 and 1 microg/ml for mycrocysts treatment and 10, 5, and 1 microg/ml for murine cysts treatment. In vivo treatment was performed on 20 mice that developed an experimental secondary hydatid disease over a period of 11 months. FLBZ was given (1.5 mg/kg) by the oral route once a day for 50 days. A loss of turgidity was detected in all in vitro drug treated cysts irrespective of the drug concentration or parasite origin. Inspection of treated cysts by scanning electron microscopy (SEM) revealed that the germinal layer lost it characteristic multicelular structure. These results were confirmed on the ultrastructural level by transmission electron microscopy (TEM), treated metacestodes had undergone considerable degenerative changes after the in vitro treatment. The results obtained after the in vivo treatment with FLBZ showed no significant difference between the control and treated groups related to the weight of cyst masses. However, the ultrastructural study at TEM of cysts that developed in mice from the treated group revealed alterations in the germinal layer with the presence of numerous vacuoles. With regard to the ultrastructural study at SEM, only cellular debris of the germinal layer could be seen. In conclusion, the data obtained clearly demonstrate that in vitro and in vivo treatment with FLBZ is effective against E. granulosus metacestodes.

Seasonal fluctuations in prevalence of dog intestinal parasites in public squares of Mar del Plata city, Argentina and its risk for humans.

The aim of this work is to analyze whether there is a seasonal prevalence of parasites in dog feces from public squares in Mar del Plata city, Argentina, and to evaluate the climatic conditions that promote the development of parasites and allow the transmission to people. The study was performed in 21 squares from June 2001 to May 2002. Samples were processed by the Willis technique. Differences in prevalence of parasites were examined for significance by the Chi-square test. Climatic data were obtained from the Library of the National Meteorological Service of Argentina. Total parasitic prevalence was higher in winter than in summer. The prevalence of Ancylostoma spp. was higher in the summer-autumn period. For Toxocara canis, the prevalence was higher in winter whereas for Trichuris vulpis, it was higher in winter, spring and summer. This work shows high prevalence of total parasites throughout the year. For Ancylostoma spp., summer and autumn might be the seasons with higher sanitary risk. On the other hand, T. canis could present the higher risk to people in winter and, T. vulpis, would be transmitted throughout the whole year. The seasonal variation in prevalence of dog parasites results in continuous exposure to people visiting the squares, not only Mar del Plata residents but also tourists from other regions of Argentina and the world, with at least one species of parasite with sanitary risk.

Paleoparasitological records in a canid coprolite from Patagonia, Argentina.

In this note, organic remains identified as a canid coprolite were examined. The material was dated at 6540 +/- 110 B.P.; it was collected in the Perito Moreno National Park, Santa Cruz, Argentina. Paleoparasitological analysis was performed following standard procedures. Coprolite fragments were rehydrated in a trisodium phosphate aqueous solution and subjected to spontaneous sedimentation for microscope analysis. Eggs of nematodes identified as Trichuris sp., Capillaria sp., Uncinaria sp., and an ascaridid (probably Toxascaris sp.) or spirurids (presumably Physaloptera sp.), plus a cestode (Anoplocephalidae), presumably Moniezia sp., were found.

In vitro effects of flubendazole on Echinococcus granulosus protoscoleces.

The aim of the present work was to determine the in vitro protoscolicidal effect of flubendazole (FLBZ) against Echinococcus granulosus. Protoscoleces of E. granulosus were incubated with FLBZ at concentrations of 10, 5 and 1 microg/ml. The first signs of FLBZ-induced damage were observed 3 days post-incubation. A clear protoscolicidal effect, reducing the vitality of protoscoleces to 35.6+/-0.7%, was observed after 18 days of incubation. After 25 days of FLBZ incubation (5 microg/ml), the percentage of vital protoscoleces was 13.9+/-5.9%. Protoscolex mortality was 100% (10 and 1 microg/ml) and 0.7+/-0.7% (5 microg/ml) after FLBZ incubation for 30 days. Results of vitality tests were consistent with the tissue damage observed at the ultrastructural level. The primary site of damage was the tegument of the parasite. The morphological changes included contraction of the soma region, formation of blebs on the tegument, rostellar disorganization, loss of hooks and destruction of microtriches. The data reported in this article demonstrate a clear in vitro effect of FLBZ against E. granulosus protoscoleces.

Strain characterization of Echinococcus granulosus protoscoleces of cattle origin using the in vitro vesicular development.

The aim of this work was to characterize the strain of protoscoleces of E. granulosus of cattle origin using the in vitro vesicular development. The in vitro development of these samples was compared to samples of sheep origin determined previously by genetic analyses as common sheep strain (G1). There were similarities between sheep and cattle samples not only in the time of microcysts formation, but also in the development process. Vesiculated protoscoleces and protoscoleces with posterior bladders appeared during the first week of incubation. After 14 days of culture, a laminated layer appeared like a fine membrane in one of the extremes of the protoscoleces. In the sheep samples, microcysts were observed between 19 and 20 days. In the cattle samples, microcysts appeared between 20 and 23 days. The coincidence between the development times and physiological characteristics found in the present study may indicate that the parasites from cattle and sheep were of the same strain.

Echinococcus granulosus: first report of microcysts formation from protoscoleces of cattle origin using the in vitro vesicular culture technique.

The aim of this work was the achievement of microcysts formation from protoscoleces of E. granulosus of cattle origin using the in vitro vesicular culture technique. Vesiculated protoscoleces and protoscoleces with posterior bladders appeared during the first week of incubation. After 14 days of culture, a laminated layer appeared like a fine membrane in one of the extremes of the protoscoleces. On day 20, some microcysts with a complete laminated layer were observed. By day 48, microcysts completely developed could be observed. This is the first study where microcysts formation was obtained using protoscoleces of E. granulosus of cattle origin.

Viscachataenia n. g., with the redescription of V. quadrata (von Linstow, 1904) n. comb. (Cestoda: Anoplocephalidae) in Lagidium viscacia (Rodentia: Chinchillidae) from Argentina.

A new genus, Viscachataenia, is erected to accommodate the anoplocephalid cestode Cittotaenia quadrata von Linstow, 1904, based on a redescription of the species from material collected from the chinchillid rodent Lagidium viscacia in Argentina. The new genus is characterised by paired genitalia, a reticulate uterus and the vagina entering the genital atrium anterior to the cirrus-sac. Viscachataenia therefore has similarities with Monoecocestus Beddard, 1914, a genus which is common in South American rodents but which has a single set of genitalia in each segment. Cittotaenia viscaciae (Spasskii, 1951) and Bertiella findlayi Mazza, Parodi & Fiora, 1932, also from viscachas, are considered synonyms of V. quadrata.