Intestinal Life Cycle of Eimeria caliginosa (Apicomplexa: Eimeriidae) From the Dusky Rice Rat, Melanomys caliginosus (Rodentia: Cricetidae: Sigmodontinae), In Costa Rica.

The endogenous life cycle of Eimeria caliginosa was studied in experimentally infected dusky rice rats, Melanomys caliginosus. All endogenous stages were located in the epithelial cells of villi in the small intestine. Both Giemsa-stained mucosal scrapings and histological sections were studied for the diagnosis of all the life-cycle stages. Eimeria caliginosa has 3 generations of meronts (M) that differ by size, shape, and number of merozoites (m), which also differ in their size, shape, and location of their nuclei within the cytoplasm of the meronts. The 3 meront types, M1-M3, respectively, had 20-33 (m1), 5-9 (m2), and 13-16 (m3) merozoites. Macrogametocytes and microgametocytes, as well as macrogametes and microgametes, completed the sexual cycle, which concludes with the formation of unsporulated oocysts. This parasite's endogenous development produced severe intestinal lesions in the experimentally infected dusky rice rats. In our ongoing work to understand the biodiversity present in plants and animals of the protected Reserva Biológica Alberto Manuel Brenes (ReBAMB) field station in Costa Rica, we now have discovered 3 new Eimeria species, and this is the second complete life cycle in which we document both the asexual and sexual stages.

Endogenous Life Cycle of Eimeria melanomytis (Apicomplexa: Eimeriidae) from the Dusky Rice Rat, Melanomys caliginosus (Rodentia: Cricetidae: Sigmodontinae) in Costa Rica.

Endogenous stages of the life cycle of Eimeria melanomytis, infecting the peripheral epithelial cells of villi of the small intestine of experimentally infected young dusky rice rats, Melanomys caliginosus , were studied. Giemsa-stained mucosal scrapings and histological sections were examined for all the stages. Eimeria melanomytis has 3 generations of meronts (M), different in size, shape, and number of merozoites (m); and in size, shape, and location of the nuclei within the cytoplasm of the meronts. The 3 meront types, M1-M3, respectively, had 11-14 (m1), 7-10 (m2), and 20-30 (m3) merozoites. Macrogametocytes and microgametocytes, as well as macrogametes and microgametes, complete the sexual cycle forming the unsporulated oocysts. This parasite's endogenous development produced severe intestinal lesions in experimentally infected dusky rice rats.

Endogenous Life Cycle of Eimeria marmosopos (Apicomplexa: Eimeriidae) from the Opossum, Didelphis marsupialis (Didelphimorphia: Didelphidae) in Costa Rica.

The endogenous life cycle of Eimeria marmosopos was studied in experimentally infected young opossums, Didelphis marsupialis . All the endogenous stages were located in the epithelial cells of villi in the small intestine. Giemsa-stained mucosal scrapings and histological sections were studied for the diagnosis of all the life cycle stages. Eimeria marmosopos has 3 generations of meronts (M) that differ by size, shape, and number of merozoites (m), which also differ in their size, shape, and location of their nuclei within the cytoplasm of the meronts. The 3 meront types, M(1)-M(3), respectively, had 8-15 (m(1)), 4-9 (m(2)), and 22-30 (m(3)) merozoites. Macrogametocytes and microgametocytes, as well as macrogametes and microgametes, completed the sexual cycle, finishing with the formation of unsporulated oocysts. This parasite's endogenous development produced severe intestinal lesions in experimentally infected opossums. There are 56 Eimeria species known from all marsupials worldwide, but this is the first complete life cycle in which both the asexual and sexual stages have been documented.

A new species of Eimeria Schneider, 1875 (Apicomplexa: Eimeriidae) from the dusky rice rat Melanomys caliginosus (Tomes) (Mammalia: Rodentia) in Costa Rica.

We collected faecal samples from 24 dusky rice rats, Melanomys caliginosus (Tomes) (Rodentia: Cricetidae: Sigmodontinae), in a Biological Reserve in Costa Rica, and found three (12.5%) to be infected with a species of Eimeria Schneider, 1875, which we describe here as new. Sporulated oöcysts of Eimeria caliginosa n. sp. are almost spheroidal and measure 16-21 × 17-20 (mean 19.6 × 18.2) µm; micropyle, oöcyst residuum and polar granule are absent. Sporocysts are ovoidal, 9-13 × 6-8 (mean 11.2 × 6.7) µm, with small Stieda and sub-Stieda bodies present, but a para-Stieda body is absent; the sporocyst residuum is a compact mass of c.11-15 granules, c.5 µm wide. Sporozoites are crescent-shaped, 5-8 × 2-3 (mean 6.8 × 2.4) µm. This is the third species of Eimeria described from the genus Melanomys Thomas.

Two new Eimeria spp. (Apicomplexa: Eimeriidae) from the dusky rice rat, Melanomys caliginosus, Tome 1860, in Costa Rica.

We collected fecal samples from 9 dusky rice rats, Melanomys caliginosus (Rodentia, Cricetidae, Sigmodontinae), in a Biological Reserve in Costa Rica and found 8 (89%) to be infected with 2 Eimeria species which we describe here as new. Sporulated oocysts (n = 20) of the first, Eimeria melanomytis n. sp., are cylindroidal and measure 20.1 × 13.3 µm (18-23 × 13-15); micropyle and oocyst residuum are both absent, but a bilobular polar granule is present. Its sporocysts are ovoidal, 10.5 × 7.4 µm (10-13 × 6-8) with a small Stieda body, but both substieda and parastieda bodies are absent; a spheroidal sporocyst residuum is present, ≈ 5 µm wide. Sporulated oocysts (n = 20) of the second, Eimeria rebambensis n. sp., are subspheroidal, 21.2 × 17.0 µm (19-23 × 14-18); micropyle and oocyst residuum are both absent, but with a polar granule ≈ 2 µm wide. Sporocysts are elongate-ovoidal, 12.4 × 7.0 µm (11-14 × 6-9) with a distinct knob-like Stieda body, and a substieda body directly beneath it which is about twice as wide, but no parastieda body is present; the sporocyst residuum is an irregular mass composed of 8-10 globules scattered among the sporozoites, which are ≈ 10 × 5 µm, and have 1 refractile body at their wider end and a central nucleus. These are the first eimerians described from this rodent genus.

In vitro antimalarial activity of extracts of some plants from a biological reserve in Costa Rica

Treatment with the usual antimalarial drugs, have induced parasite resistance, reinforcing the need to finding natural antimalarial components that would be found on plants from the forest. Therefore, we decided to look for these components in Costa Rican plants from a protected forest area. Fresh and dry extracts of roots, bark, leaves, flowers and fruits of 25 plants from a biological reserve in Costa Rica, Reserva Biológica Alberto Manuel Brenes (REBAMB), were studied in vitro for the presence of substances with antimalarial activity. By studying the inhibition of P. berghei schizogony, we assessed the antimalarial activity of several plant extracts: Aphelandra aurantiaca, A. tridentata (Acanthaceae); Xanthosoma undipes (Araceae); Iriartea deltoidea (Arecaceae); Neurolaena lobata (Asteraceae); Senna papillosa, Pterocarpus hayessi, Lonchocarpus pentaphyllus (Fabaceae); Nectandra membranacea, Persea povedae, Cinamomum chavarrianum (Lauraceae); Hampea appendiculata (Malvaceae); Ruagea glabra, Guarea glabra (Meliaceae); Psidium guajava (Myrtaceae); Bocconia frutescens (Papaveraceae); Piper friedrichsthalii (Piperaceae); Clematis dioica (Ranunculaceae); Prunus annularis (Rosaceae); Siparuna thecaphora (Siparunaceae); Solanum arboreum, Witheringia solanácea (Solanaceae); Ticodendrum incognitum (Ticodendraceae); Heliocarpus appendiculatus (Tiliaceae) and Myriocarpa longipes (Urticaceae). We used different parts of the plants as well as fresh and dried extracts for testing IC50. The solid content of the extracts ranged from 1-71.9μg/mL. The fresh extracts showed stronger activity than the dry ones. Since the plants showing the strongest antimalarial activity are very common in Central America, and some similar genera of these plants have shown positives results in South America, we considered important to present these findings for discussion. On the other hand, this is the first systematic study of this kind ever realized in a circumscribed and protected area of Costa Rica. Rev. Biol. Trop. 60 (2): 881-891. Epub 2012 June 01.

El tratamiento con las drogas antimaláricas de uso común han inducido resistencia por parte del parásito, lo que obliga a buscar en las plantas de los bosques, componentes naturales con actividad en contra de esta enfermedad. Por lo tanto, decidimos buscar dichos componentes en plantas de una Reserva Forestal de Costa Rica. Extractos tanto frescos como secos de raíz, corteza, hojas, flores y frutos, de 25 plantas de la Reserva Biológica Alberto Manuel Brenes (REBAMB), fueron estudiados in vitro en busca de sustancias con actividad antimalárica. Las plantas estudiadas fueron: Aphelandra aurantiaca, A. tridentata (Acanthaceae); Xanthosoma undipes (Araceae); Iriartea deltoidea (Arecaceae); Neurolaena lobata (Asteraceae); Senna papillosa, Pterocarpus hayessi, Lonchocarpus pentaphyllus (Fabaceae); Nectandra membranacea, Persea povedae, Cinamomum chavarrianum (Lauraceae); Hampea appendiculata (Malvaceae); Ruagea glabra, Guarea glabra (Meliaceae); Psidium guajava (Myrtaceae); Bocconia frutescens (Papaveraceae); Piper friedrichsthalii (Piperaceae); Clematis dioica (Ranunculaceae); Prunus annularis (Rosaceae); Siparuna thecaphora (Siparunaceae); Solanum arboreum, Witheringia solanacea (Solanaceae); Ticodendrum incognitum (Ticodendraceae); Heliocarpus appendiculatus (Tiliaceae) y Myriocarpa longipes (Urticaceae). Los extractos frescos y secos de las diferentes partes de las plantas fueron estudiadas y se determinó la IC50, el cual osciló entre 1-71.9mg/mL; los extractos frescos mostraron mayor actividad antimalárica. Las plantas que presentaron mayor actividad son muy comunes en Centroamérica y algunos géneros similares, aunque no las mismas especies, han sido encontrados positivos en América del Sur; por esta razón consideramos importante estos resultados como información y materia de discusión en este tema. Además este es el primer estudio sistemático de esta naturaleza realizado en un área boscosa circunscrita y protegida de Costa Rica.

Molecular systematics and phylogeography of Cebus capucinus (Cebidae, Primates) in Colombia and Costa Rica by means of the mitochondrial COII gene.

We propose the first molecular systematic hypothesis for the origin and evolution of Cebus capucinus based on an analysis of 710 base pairs (bp) of the cytochrome c oxidase subunit II (COII) mitochondrial gene in 121 C. capucinus specimens sampled in the wild. The animals came from the borders of Guatemala and Belize, Costa Rica, and eight different departments of Colombia (Antioquia, Chocó, Sucre, Bolivar, Córdoba, Magdalena, Cauca, and Valle del Cauca). Three different and significant haplotype lineages were found in Colombia living sympatrically in the same departments. They all presented high levels of gene diversity but the third Colombian gene pool was determined likely to be the most ancestral lineage. The second Colombian mitochondrial (mt) haplogroup is likely the source of origin of the unique Central America mt haplogroup that was detected. Our molecular population genetics data do not agree with the existence of two well-defined subspecies in Central America (limitaneus and imitator). This Central America mt haplogroup showed significantly less genetic diversity than the Colombian mt haplogroups. All the C. capucinus analyzed showed evidence of historical population expansions. The temporal splits among these four C. capucinus lineages were related to the completion of the Panamanian land bridge as well as to climatic changes during the Quaternary Period.

[Parasitic infections of coyote, Canis latrans (Carnivora: Canidae) in a Costa Rican National Park and a surrounding agricultural area]. / Infecciones parasitarias del coyote, Canis latrans (Carnivora: Canidae) en un Parque Nacional y una zona agrícola en Costa Rica.

As human populations expand into wild habitats with their pets and livestock, the potential spread of disease to wildlife or vice versa increases. Because, wild and domestic canids may pose as reservoirs or disseminators of infectious diseases (including parasites), coyotes (Canis latrans) may also serve as indicators of ecological health. In Costa Rica, little information exists on coyote parasites, making research necessary to identify potential zoonotic interactions. For this reason, a survey of the coyote parasites was performed in a mixed area of protected woodland and agricultural land, surrounding Irazú Volcano National Park (IVNP) in Cartago, Costa Rica. Over a one-year period, 209 fecal samples were collected directly from the ground. Collection took place on a monthly basis in a trail sectioned into three sub-areas named Irazú (closest to the volcano), potato fields (where potatoes were cultivated), and Prusia (a protected sector of IVNP). Sectioning the trail allowed separate collection and analysis of the samples, where 99 were obtained from Irazú, 11 from potato fields and 99 from Prusia. Using direct examination and mechanical concentration 36.84% positive samples containing at least one helminth were found. The presence of parasites was similar for both woodland areas (33.3% in Prusia and 37.4% in Irazú), but differed from the 63.6% observed in the potato fields. Hookworm parasites (probably Ancylostoma caninum), threadworms (possibly Strongyloides sp.), Toxocara canis, Trichuris sp. and Taenia pisiformis were identified, as well as Hymenolepis diminuta, possible spurious parasite resulting from the ingestion of rodents by coyotes. Seasonal details are discussed, concluding that wet and dry seasons affect presence of parasites. Some remarks are made on the importance of these first findings for Costa Rica, especially considering the systematic way in which the collection of samples was carried out.

In vitro antimalarial activity of extracts of some plants from a biological reserve in Costa Rica.

Treatment with the usual antimalarial drugs, have induced parasite resistance, reinforcing the need to finding natural antimalarial components that would be found on plants from the forest. Therefore, we decided to look for these components in Costa Rican plants from a protected forest area. Fresh and dry extracts of roots, bark, leaves, flowers and fruits of 25 plants from a biological reserve in Costa Rica, Reserva Biol6gica Alberto Manuel Brenes (REBAMB), were studied in vitro for the presence of substances with antimalarial activity. By studying the inhibition of P berghei schizogony, we assessed the antimalarial activity of several plant extracts: Aphelandra aurantiaca, A. tridentata (Acanthaceae); Xanthosoma undipes (Araceae); Iriartea deltoidea (Arecaceae); Neurolaena lobata (Asteraceae); Senna papillosa, Pterocarpus hayessi, Lonchocarpus pentaphyllus (Fabaceae); Nectandra membranacea, Persea povedae, Cinamomum chavarrianum (Lauraceae); Hampea appendiculata (Malvaceae); Ruagea glabra, Guarea glabra (Meliaceae); Psidium guajava (Myrtaceae); Bocconia frutescens (Papaveraceae); Piper friedrichsthalii (Piperaceae); Clematis dioica (Ranunculaceae); Prunus annularis (Rosaceae); Siparuna thecaphora (Siparunaceae); Solanum arboreum, Witheringia solanacea (Solanaceae); Ticodendrum incognitum (Ticodendraceae); Heliocarpus appendiculatus (Tiliaceae) and Myriocarpa longipes (Urticaceae). We used different parts of the plants as well as fresh and dried extracts for testing IC50. The solid content of the extracts ranged from 1-71.9 microg/mL. The fresh extracts showed stronger activity than the dry ones. Since the plants showing the strongest antimalarial activity are very common in Central America, and some similar genera of these plants have shown positives results in South America, we considered important to present these findings for discussion. On the other hand, this is the first systematic study of this kind ever realized in a circumscribed and protected area of Costa Rica.

Parasitosis intestinal en monos capuchinos cariblancos Cebus capucinus (Primates: Cebidae) de un área protegida en la provincia de Limón, noreste de Costa Rica

Intestinal parasites in white-faced capuchin monkeys Cebus capucinus Primates: Cebidae) inhabiting a protected area in the Limón province of Northeastern Costa Rica. Deforestation of tropical forests is threatening monkey biodiversity and their health status, dependent of an ecologically undisturbed area. To asses this relationship, we analyzed parasite occurrence in their intestines. The study was conducted at the Estación Biológica La Suerte (EBLS), Limón, Costa Rica. The group of white-faced capuchin monkeys (Cebus capucinus) was observed between March and December of 2006. A total of 75 feces samples were obtained. Once a sample was collected, the eaten plant type was identified to family and species level, and feces were processed in the laboratory to determine parasite incidence. Results showed that Moraceae was the most represented family in the samples. Among parasites, Strongyloides spp. and Acanthocephala were the most common. Positive prevalence of parasites was found similar and independent of sex and age of capuchin individuals. Microsporids were mainly reported in feces associated with Piperaceae. A low presence of these parasites was found in samples associated with Myrtaceae, with possible anti-parasite active components. The occurrence of parasites was relatively high in EBLS, when compared to other regions in Costa Rica. The higher occurrence of parasites observed in capuchins at EBLS may be due to the fact that this rain forest is surrounded by areas affected by human activities. We suggest the promotion of research in neotropical primates parasitology, for a better comprehension of the parasite-host relationship, and in a long term, being able to understand the ecosystems where they coexist, and consequently, preserve the biodiversity of the whole region. Rev. Biol. Trop. 58 (4): 1335-1346. Epub 2010 December 01.

La deforestación de bosques tropicales está amenazando la biodiversidad de las especies de primates y su estado de salud, dependiente de un lugar ecológicamente equilibrado. Con el fin de evaluar esta relación, se analizó la presencia de parásitos en los intestinos de esta especie. El estudio se realizó en la Estación Biológica La Suerte (EBLS), Limón, Costa Rica. El grupo de monos capuchinos cariblancos (Cebus capucinus) fue observado entre marzo y diciembre de 2006. Se recolectaron 75 muestras de heces a las que se les identificó las plantas ingeridas, y se procesaron en el laboratorio para evaluar la prevalencia de parásitos. Moraceae fue la familia de plantas más reportada. Strongyloides spp. y acantocéfalos fueron los más comunes. La distribución positiva de las mismas fue similar independientemente del sexo y la edad. Microsporidios se reportaron mayoritariamente en heces asociadas con la familia Piperaceae. Fue encontrada una baja existencia de éstos parásitos en muestras asociadas con Myrtaceae en cuyo género Psidium, se han reportado compuestos activos antiparasitarios. La aparición de parásitos fue relativamente mayor en la EBLS, comparado con muestras de otras regiones más secas de Costa Rica. Por lo tanto, esa expresión parasitaria puede deberse al hecho de ser la EBLS una selva lluviosa, además de estar rodeada por zonas con actividades antrópicas. Se sugiere incrementar las investigaciones de parasitología de campo en primates neotropicales con el fin de entender plenamente las relaciones parásitos-hospederos, para en un largo plazo poder comprender los ecosistemas donde conviven, y en consecuencia, preservar la diversidad biológica.

[Intestinal parasites in white-faced capuchin monkeys Cebus capucinus (Primates: Cebidae) inhabiting a protected area in the Limón province of Northeastern Costa Rica]. / Parasitosis intestinal en monos capuchinos cariblancos Cebus capucinus (Primates: Cebidae) de un área protegida en la provincia de Limón, noreste de Costa Rica.

Deforestation of tropical forests is threatening monkey biodiversity and their health status, dependent of an ecologically undisturbed area. To asses this relationship, we analyzed parasite occurrence in their intestines. The study was conducted at the Estación Biológica La Suerte (EBLS), Limón, Costa Rica. The group of white-faced capuchin monkeys (Cebus capucinus) was observed between March and December of 2006. A total of 75 feces samples were obtained. Once a sample was collected, the eaten plant type was identified to family and species level, and feces were processed in the laboratory to determine parasite incidence. Results showed that Moraceae was the most represented family in the samples. Among parasites, Strongyloides spp. and Acanthocephala were the most common. Positive prevalence of parasites was found similar and independent of sex and age of capuchin individuals. Microsporids were mainly reported in feces associated with Piperaceae. A low presence of these parasites was found in samples associated with Myrtaceae, with possible anti-parasite active components. The occurrence of parasites was relatively high in EBLS, when compared to other regions in Costa Rica. The higher occurrence of parasites observed in capuchins at EBLS may be due to the fact that this rain forest is surrounded by areas affected by human activities. We suggest the promotion of research in neotropical primates parasitology, for a better comprehension of the parasite-host relationship, and in a long term, being able to understand the ecosystems where they coexist, and consequently, preserve the biodiversity of the whole region.

Prevalence of fur mites (Acari: Atopomelidae) in non-human primates of Costa Rica.

Parasites have been investigated for some New World primates; however, very little is known about ectoparasites and specifically fur mites. In this study, Alouatta palliata, Cebus capucinus, Saimiri oerstedii, and Ateles geoffroyi monkeys from different areas of Costa Rica were searched for fur mites. A total of 276 monkeys were evaluated, and 51 of them were positive for mites of the family Atopomelidae. Listrocarpus alouattae was identified on 22.3% of A. palliata; Listrocarpus capucinus on 12.8% of C. capucinus; and Listrocarpus costaricensis on 36.8% of S. oerstedii; No fur mites were found on A. geoffroyi. Sex was not considered a determinant of mite infestation, but prevalence was significantly higher in the Central Volcanic Mountain Range Conservation Area for L. alouattae (p=0.01) and in the Central Pacific Conservation Area for L. capucinus (p=0.002). These primate fur mites are highly host-specific. Differences in the geographical distribution may be due to monkey behavior and history, as well as to environmental conditions.

Prevalence of fur mites (Acari: Atopomelidae) in non-human primates of Costa Rica

Parasites have been investigated for some New World primates; however, very little is known about ectoparasites and specifically fur mites. In this study, Alouatta palliata, Cebus capucinus, Saimiri oerstedii, and Ateles geoffroyi monkeys from different areas of Costa Rica were searched for fur mites. A total of 276 monkeys were evaluated, and 51 of them were positive for mites of the family Atopomelidae. Listrocarpus alouattae was identified on 22.3% of A. palliata; Listrocarpus capucinus on 12.8% of C. capucinus; and Listrocarpus costaricensis on 36.8% of S. oerstedii; No fur mites were found on A. geoffroyi. Sex was not considered a determinant of mite infestation, but prevalence was significantly higher in the Central Volcanic Mountain Range Conservation Area for L. alouattae (p=0.01) and in the Central Pacific Conservation Area for L. capucinus (p=0.002). These primate fur mites are highly host-specific. Differences in the geographical distribution may be due to monkey behavior and history, as well as to environmental conditions. Rev. Biol. Trop. 57 (1-2): 353-360. Epub 2009 June 30.

Muy poco se conoce sobre los ectoparásitos, específicamente de los ácaros del pelo, de primates del Nuevo Mundo. En este estudio se buscaron ácaros del pelo en monos Alouatta palliata, Cebus capucinus, Saimiri oerstedii y Ateles geoffroyi provenientes de diferentes áreas de Costa Rica. Se evaluaron 276 monos en total y 51 de ellos se encontraron positivos por ácaros de la familia Atopomelidae. Se identificó Listrocarpus alouattae en el 22.3% de los A. palliata, Listrocarpus capucinus en el 12.8% de los C. capucinus y Listrocarpus costaricensis en el 36.8% de los S. oerstedii. El sexo no fue un determinante de la infestación por ácaros, pero la prevalencia de L. alouattae fue significativamente mayor en el Área de Conservación Cordillera Volcánica Central (p=0.01) y la de L. capucinus fue mayor en el Área de Conservación Pacífico Central (p=0.002). Estos ácaros del pelo de primates son altamente específicos en relación con su hospedero. Las diferencias en la distribución geográfica podrían deberse al comportamiento e historia de los monos, así como a las condiciones ambientales.

Parásitos en monos carablanca Cebus capucinus (Primates: Cebidae) de Costa Rica / Parasites of white face monkeys (Cebus capucinus) (Primates: Cebidae) of Costa Rica

Fecal samples of 53 white face monkeys (Cebus capucinus) from some sites of Costa Rica were studied for blood and intestinal parasites. Animals were anesthetized with darts containing Telazol, blood and fecal samples were collected and all the material was studied in the laboratory. For blood parasites, Giemsa stain andKnott concentration was performed. Intestinal parasites were studied by direct examination in 0,85 percent saline solution and a Iodine solution. Haematoxylin stain was used for better protozoa identification. Strongyloides sp, hookworms, acanthocephalid eggs and other nematodes, as well as Tritrichomonas sp (more frequent) and other protozoa were found. The presence of at least one parasites was observed in 33.3 percent to 100 percent of the fecal samples with an average of 73.6 percent. There was not any correlation between sex and infection rate, but the presence of parasite was higher in heavier (older) animals. Microfllarias were the only blood organism detected.The reasons for these high infection rates could be explained for feed diversity, contaminated soil and water contact and sociability of these animals, among other factors.

Se capturaron y anestesiaron un total de 53 primates de la especie Cebus capucinus por medio de dardos con tiletamina de diferentes zonas de Costa Rica. Todos los animales fueron estudiados por la presencia de parásitos sanguíneos e intestinales. En la sangre sólo se encontraron microfilarias (24,5 por ciento) las cuales fueron diagnosticadas usando la concentración de Knott y la tinción de Giemsa. Los parásitos intestinales fueron observados en forma directa y algunos de los protozoos también fueron tejidos con hematoxilina de Heidenhain. Los parásitos encontrados fueron Strongyloides sp, uncinarias, acantocéfalos y otros nemátodos no identificados, en porcentajes que variaron según las zonas de captura. Los índices de infección determinados por la presencia de al menos un parásito fluctuaron entre 33,3 por ciento y el 100 por ciento con una media general del 73,6 por ciento, no existiendo diferencias de infección en cuanto al sexo de los animales. En general se notó un mayor grado de infección en los animales de más peso (más edad) tal y como se ha observado en otros países. Se considera que las infecciones parasitarias son más elevadas en esta especie, posiblemente por tener una alimentación más variada, un mayor contacto con el suelo y aguas contaminadas, así como la gran sociabilidad de estos monos. La presencia de estos parásitos podría ser una de las causas, entre otras para acelerar el riesgo de extinción de los primates en Costa Rica y en América.

[In vitro growth kinetics of two Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae) clones in myocardial cells from rodents of different susceptibility]. / Cinética de crecimiento in vitro de dos cepas de Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae) en células miocárdicas de roedores con diferente susceptibilidad.

In vitro growth kinetics of two Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae) clones in myocardial cells from rodents of different susceptibility. Two Trypanosoma cruzi isolates, TCR-4 from Costa Rica and UES-1 from El Salvador, were studied in vitro to compare their infectivity or resistance and intracellular replication in myocardial cells in three strains of mice and rats: NGP white mice, C3 H mice and Sprague Dowley rats. Myocardial cells were cultured on coverslips at 37 degrees C in a humid 10% CO2 atmosphere and then infected at a ratio of one tripomastigote per cell. Samples were studied after 24, 72, 96 and 120 h of infection to determine parasite infection capacity and intracellular multiplication. Both parasites had the highest infection capacity in C3 H mice, followed by NGP mice cells with a very low infection rate. Lastly, almost no Trypanosoma cruzi multiplication was observed in Sprague Dowley rats, suggesting a strong natural resistance in this animal to both strains of the parasite. The UES-1 isolate presented higher multiplication and greater invasion than the TCR-4 strain, showing greater virulence of UES-1 in heart cells, at least in vitro.

Enfermedad de Chagas en Costa Rica: estudio comparativo en dos épocas diferentes / Chagas disease in Costa Rica: comparative study in two different stages

Para actualizar la situación de la Enfermedad de Chagas en Costa Rica se realizó un estudio serológico y epidemiológico parcial en 4 zonas de riesgo en el país. Un total de 1.561 estudiantes de 6 a 12 años fueron estudiados por anticuerpos contra T.cruzi usando una prueba de ELISA como tamiz previo a una confirmatoria. En la primera prueba se obtuvo una positividad que osciló entre 0,6 por ciento y 14,9 por ciento mientras que en la prueba confirmatoria esta positividad fue de 0,1 por ciento. El estudio del 10 por ciento de las casas de los estudiantes seleccionados indicó índices de infestación del 2,9 por ciento al 9,3 por ciento y los triatominos, encontrados peridomiciliarmente presentaron un 8,1 por ciento de infección por T. cruzi. Al comparar estos datos con los conocidos antes de 1980 y basados en un análisis socioeconómico de ambas épocas, se concluye que las mejores condiciones de vida actuales han disminuido la incidencia de Enfermedad de Chagas en Costa Rica.

Presencia de Plasmodium brasilianum (Apicomplexa, Plasmodidae) en el mono congo (Alouatta palliata, Primates: Cebidae) de Costa Rica: importancia epidemiológica en relación con el ser humano / Plasmodium brasilianum (Apicomplexa, Plasmodidae) in the congo monkey Alouatta brasilianum (Primate: Cebidae) of Costa Rica: epidemiological importance related to human

La especie productora de malaria en primates, Plasmodium brasilianum, fue encontrada por primera vez en Costa Rica en 6 de 104 ejemplares de monos congo o aulladores (Alouatta palliata). Los animales fueron capturados y anestesiados por medio de dardos que contenían hidrocloruro de tiletamina y zolazepam (Zoletil®) combinados en partes iguales. Para estudiar estos animales por parásitos sanguíneos, se prepararon frotis sanguíneos que luego se tiñeron y se estudiaron en el laboratorio, encontrándose las formas de trofozoitos jóvenes o avanzados así como gametocitos y esquizontes. La morfología característica de algunos estados evolutivos, como por ejemplo, las formas en banda de trofozoitos avanzados y los esquizontes en forma de margarita o "rosetta" permitieron el diagnóstico de la especie. Puesto que se han encontrado casos humanos infectados con este organismo y éste es casi indiferenciable de Plasmodium malariae, una especie parásita del ser humano, se discute el hallazgo de este parásito desde un punto de vista epidemiológico en el área de la salud.

Heterogeneidad en la metaciclogénesis in vitro de clones derivados de una cepa costarricense de Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae) / Heterogenity in the vitro metacyclogenesis of clones derived from a Costa Rican strain of Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae)

La metaciclogénesis in vitro fue evaluada en la cepa costarricense de Trypanosoma cruzi denominada TC-4 y en tres clones derivados de la misma como un criterio de heterogeneidad biológica entre clones y cepa parental. Los clones fueron obtenidos de colonias, resultado del cultivo de los parásitos en agar sangre al 40%. Estos clones fueron denominados TC-4 α; TC-4 β; y TC-4 π y fueron mantenidos en agar sangre difásico 40% con infusión cerebro-corazón al 3,7% como fase líquida. La metaciclogénesis fue inducida por incubación de los parásitos en orina artificial de triatomino suplementada con L-prolina (OAT+P) a temperatura constante (27ºC). El progreso en la metaciclogénesis fue diariamente monitoreado determinando el radio tripomastigotos/epimastigotos, el porcentaje de tripomastigotos metacíclicos y la concentración de tripomastigotos metacíclicos (TM/mL). La variabilidad fue evaluada mediante pruebas de ANDEVA para mediciones repetidas (a: 0,05). Los indicadores de metaciclogénesis mostraron sus valores máximos entre las 72 y 96 horas después del inicio del experimento, intervalo donde se observaron diferencias estadísticamente significativas entre algunos de los sistemas celulares (p < 0,05). Estas observaciones pueden sugerir que la composición clonal de cada cepa de T. cruzi puede determinar la infectividad del parásito para el hospedador vertebrado.

Cinética multiplicativa de clones de Crithidia fasciculata (Kinetoplastida: Trypanosomatidae) en un sistema de cultivo in vitro / Multiplicative kinetics of Crithidia fasciculata (Kinetoplastida: Trypanosomatidae) clones in an in vitro culture system

La cinética multiplicativa de la cepa parental y cinco clones de Crithidia fasciculata (Kinetoplastida: Trypanosomatidae) fue estudiada en agar sangre 40% difásico. Los clones fueron obtenidos de cultivos en agar sangre 40% y denominados Ia, IIIa, IVa, Va y CAA. En cada caso, tubos de agar sangre 40% difásico con infusión cerebro corazón 3,7 % como fase líquida fueron inoculados con 103 coanomastigotos de cada clon y la cepa parental. La concentración de parásitos fue estimada semanalmente durante 12 semanas expresando las concentraciones en coanomastigotos/mm3. La variabilidad fue evaluada por análisis de variancia (ANDEVA) para mediciones repetidas (a:0,05) realizadas durante cada día de observación. Electroforesis en geles de poliacrilamida con dodecil sulfato de sodio (SDS-PAGE) fueron también efectuadas para evaluar los perfiles proteicos de los clones y la cepa parental. Los resultados mostraron una fase de crecimiento logarítmico muy corta que antecedió a una fase estacionaria prolongada. (p > 0,05). No hubieron diferencias estasdísticamente significativas entre la concentración de coanomastigotos/mm3 entre los sistemas estudiados durante cada día de observación. Los perfiles proteicos mostraron patrones altamente homogéneos en todos los sistemas estudiados. Los resultados sugieren que las menores presiones evolutivas que sufre naturalmente C. fasciculata en su ciclo propagativo podrían estar relacionadas con la homogeneidad observada, pero es requerida más información en tópicos como inmunología, biología y genética para demostrar dicha homogeneidad.

Trypanosoma lewisi-induced immunosuppression: the effects on alveolar macrophage activities against Cryptococcus neoformans.

The immunosuppressive effect of Trypanosoma lewisi infection on alveolar macrophage (AM) activities against Cryptococcus neoformans was studied in an animal model. Two groups of rats were treated with T. lewisi and killed after 4 (4d-rats) and 7 days (7d-rats), respectively. A third group not given T. lewisi, served as control. AM were challenged in vitro with C. neoformans. Phagocytosis was assessed with a fluorescence method. Superoxide anion production was evaluated with the nitroblue tetrazolium (NBT) test. The survival of cryptococci was estimated by counting colony-forming units. The numbers of detached AM from culture plates were determined using a Bürker chamber. The NBT response, adhesion to plate surface and killing activity, but not the phagocytosis of AM from 4d-rats were significantly impaired compared to control or 7d-rats. Thus, T. lewisi causes transitory immunosuppressive effects on AM activities. This rapid T. lewisi immunosuppression model may be useful to study new approaches to anticryptococcal therapy.