Por cuanto el molusco Achatina fulica nativo del África es vector de helmintos, pero su relación con protozoarios y bacterias es poco conocida, decidimos estudiar las excretas de 1.200 ejemplares capturados en los estados Anzoátegui, Monagas, Sucre y Nueva Esparta, del noreste de Venezuela. Su moco pedal y heces mostraron infección por los protozoarios Chilomastix spp., Trichomonas spp., Giardia spp., Balantidium spp., Entamoeba spp., Iodamoeba spp., Blastocystis spp. Y por los helmintos de los grupos Ascarioidea, Trichuroidea, Ancylostomatidae y Cestoda. El moco céfalopodal mostró únicamente larvas de Rhabditida. Las bacterias Citrobacter freundii, Escherichia coli, Klebsiella pneumoniae, K. azaenae, Aeromonas hydrophila, Acinetobacter baumannii, Pseudomonas aeruginosa, Campylobacter spp. infectaron a las tres excretas. Los mecanismos de transmisión y la composición de las excretas, como nichos fisiológicamente apropiados para los organismos encontrados, son discutidos en relación con el riesgo epidemiológico que el molusco representa en salud pública y veterinaria.

The mollusk Achatina fulica, native to Eastern Equatorial Africa, has been incriminated as a carrier or vector of helminthes. Nevertheless, information in the literature as regards its status as a carrier for bacteria is scarce, and we could find no reference at all for its relation to protozoa. We studied microscopically the excreta from 1200 snails captured in Anzoátegui, Monagas, Sucre and Nueva Esparta states, in northeast Venezuela. The pedal mucus and feces were infected by the protozoa Chilomastix spp., Trichomonas spp., Giardia spp., Balantidium spp., Entamoeba spp., Iodamoeba spp., Blastocystis spp., as well as helminthes of Ascarioidea, Trichuroidea, Ancylostomatidae and Cestoda groups. The only helminthes found in the cephalopodal mucus were Rhabditida larvae. The three excreta were also infected by the bacteria: Citrobacter freundii, Escherichia coli, Klebsiella pneumoniae, K. azaenae, Aeromonas hydrophila, Acinetobacter baumannii, Pseudomonas aeruginosa, Campylobacter spp. Risk of infection and transmission mechanisms as well as the composition of the excreta as appropriate physiological niches for the organisms mentioned, are discussed with regard to the epidemiological importance of this snail for in human and veterinary health.

Señalamos la presencia de Eratyrus mucronatus (Stal, 1859) (Hemiptera, Reduviidae, Triatominae) infectado con Trypanosoma cruzi, en un área urbana peridomiciliar (Universidad de Oriente, Núcleo de Anzoátegui, estado Anzoátegui, Venezuela) lo que representa, en nuestro conocimiento, el primer reporte de la especie para este estado. Se discute la importancia epidemiológica de este hallazgo.

The authors report the presence of Eratyrus mucronatus (Stal, 1859) (Hemiptera, Reduviidae, Triatominae) infected with Trypanosoma cruzi, in an urban peridomiciliar area (Universidad de Oriente, Núcleo de Anzoátegui, Anzoátegui state, Venezuela), what represents, to our knowledge, the first report of the species for this state. The epidemiological importance of this finding is emphasized.

Trypanosoma cruzi is usually transmitted by contact with the excreta of infected Triatominae; among non-vectorial infections, direct transmission through coitus has been proposed. We investigated this possibility by instilling, through the external meatus of the vagina and the penis of previously anesthetized NMRI albino mice, blood of mice infected with strains isolated from Didelphis marsupialis (opossum, strain CO57), Rattus rattus (rat, strain CO22) and human (strain EP). Some animals were allowed to copulate the same day of the instillation. In other experiments, the strains were inoculated in the scrotum. To determine the effect of immunosuppression, some mice were treated with cyclophosphamide 30 days post-instillation. Controls were instilled orally and ocularly. Vaginal instillation with strain CO22 produced systemic infection with tropism to the heart, skeletal muscle, skin, duodenum, pancreas, ovary and sternum. Scrotal inoculation with strain EP likewise invaded liver, spleen, lung, lymph nodes and urogenital organs; while strain CO57 invaded skeletal and cardiac muscle, pancreas, testis, and vas deferens. Penile infection with strain CO22 was detected by xenodiagnosis. Immunosuppression did not increase parasitemia of vaginally infected mice or controls. Mating did not produce infection. Our results show that contact of blood trypomastigotes of T. cruzi with genital mucosa can produce blood and tissue infections. These results are discussed in relation to reports of frequent experimental tropism of T. cruzi toward urogenital organs.

Exame direto de sangue e xenodiagnóstico de 47 roedores sinantrópicos (Rattus rattus, R. norvegicus, Mus musculus) capturados no Vale de Caracas, Venezuela, revelaram infecção por tripanosoma em 12 R. rattus, 10 com T. lewisi e 2 com T. cruzi. Dos últimos o curso de parasitemia, o pleomorfismo dos tripomastigotas na corrente sanguínea, tropismo tissular em ratos e camundongos natural e experimentalmente infectados, mortalidade dos hospedeiros, morfologia dos parasitas fecais em Rhodnius prolixus usados para xenodiagnóstico e infectividade das fezes do "barbeiro" para camundongos NMRI, foram todos característicos de Trypanosoma (Schizotrypanum) cruzi. Um rato com parasitemia patente, tinha numerosos ninhos de amastigotas no músculo cardíaco e parasitismo moderado do músculo liso do duodeno e do músculo esquelético. Camundongos inoculados com flagelados fecais de "barbeiros" tinham tropismo tissular moderado nos mesmos órgãos e também no cólon e pâncreas. O possível papel do R. rattus no estabelecimento de focos de doença de Chagas em Caracas é discutido

Direct blood examination and xenodiagnosis of 47 synanthropic rodents (Rattus rattus, R. norvegicus, Mus musculus) captured in the valley of Caracas, Venezuela, revealed trypanosomal infections in 12 R. rattus, 10 with T. lewisi and 2 with T. cruzi. Of the latter the course of parasitemia, the pleomorphism of the bloodstream trypomastigotes, tissue tropism in naturally and experimentally infected rats and mice, host mortality, morphology of fecal parasites in Rhodnius prolixus used for xenodiagnosis, and infectivity of the bug feces for NMRI mice, were all characteristic of Trypanosoma (Schizotrypanum) cruzi. One rat, with a patent parasitemia, had numerous nests of amastigotes in cardiac muscle and moderate parasitism of the smooth muscle of the duodenum and of skeletal muscle. Mice inoculated with fecal flagellates from the bugs had moderate tissue tropism in the same organs and also in the colon and pancreas. The possible role of R. rattus in the establishment of foci of Chagas’ disease in Caracas is discussed

To study the influence of host age, inoculum size, and route of infection on Trypanosoma (Herpetosoma) rangeli, 12 lots of 6.0 g albino mice (NMRI strain) were infected up. with from 25x10¹ to 25x10(6) trypomastigotes/gram body weight harvested from LIT medium. The lower inocula produced low but persistent parasitemias, while the higher inocula produced high levels of parasitemia that fell quickly, suggesting the mobilization of resistance mechanisms. In other experiments, i.p. inoculation produced higher parasitemias than s.c. inoculation, and 6.0 g mice had higher parasitemias than 16.0 or 26.0 g mice. Thus, a standard methodology would seem to be necessary in the study of the various strains and/or species that may make up the T. rangeli complex.

Para estudiar la influencia de la edad del hosvedador. del tamano del inoculo y su ruta de administración sobre la infection por Trypanosoma (Herpetosoma) rangeli, fueron inoculados i.p. 12 lotes de ratones albinos (cepa NMRI) de 6.0gdepeso con 25.0 - 2.5x10(6) metatripomastigotes/g obtenidos del medio LIT. Los inóculos mas bajos produjeron parasitemias bajas pero persistentes; los inóculos mas elevados originaron niveles altos de parasitemias que cayeron prontamente, sugiriendo la mobilization de mecanismos de resistencia a niveles diferentes de actividad. En otros experimentos, la inoculation i.p. y el uso de ratones de 6.0 g dieron parasitemias mas elevadas que cuando se usaron inoculaciones s.c. o animates de 16.0 y 26.0g. Estos resultados indican la necesidad de emplear una metodologia uniforme cuando se investigue elposible carácter heterogénico del complejo de T. rangeli.

Male mice (NMRI strain) of 3 and 5 g were inoculated i. p. with 8 x 10(6) and 9 x 10(4) metatrypomastigotes/g harvested from a 12-day-old LIT culture of Trypanosoma rangeli of the "Dog-82" strain. At regular intervals after inoculation, the animals were sacrificed and portions of heart, liver, spleen, lung, thigh, kidney, stomach, intestine, brain, sternum, and vertebral column were embedded in paraffin, sectioned, and stained with haematoxylin-eosin and Giemsa colophonium. Pathology was encountered in the first five tissues cited above. The subcutaneous, periosteal, interstitial, and peribronchial connective tissues, and later the muscle cells of the heart, were heavily parasitized by amastigotes and trypomastigotes. The possible reasons for the decrease in tissue parasitosis at the same time that the parasitemia is reaching its peak, and for the low level of inflammation in the parasitized tissues, are discussed. The observations of other workers, as well as the results described here, indicate that certain strains of T. rangeli under certain conditions may well cause pathological alterations in mammals.

Ratones machos (cepa NMRI) de 3 y 5 gr, inoculados i.p. con 8 x 10(6) y 9 x 10(4) metatripo- mastigotes/gr cosechados de cultivo LIT de 12 días de repique de la cepa "Perro-82" de Trypanosoma rangeli fueron procesados, em determinados períodos postinoculación, para seccionar y teñir con hematoxilina-eosina y Giemsa-colofonio trozos de corozón, hígado, bazo, pulmones, fémur, riñon, intestino, estómago, cerebro, cerebelo, esternón y columna vertebral. Se detallan los resultados preliminares sobre la histopatologia provocada por el T. rangeli en los cinco primeros órganos citados. Los tejidos conjuntivos subcutáneo, periosteal, intersticial y peribronquial, así como las miocélulas del corazón fueron altamente parasitados por amastigotes y tripomastigotes. Se discuten las posibles razones de la disminución del parasitismo tisular cuando la parasitemia se encontró en sus niveles máximos, así como la escasa inflamación obtenida en los tejidos parasitados. Las observaciones de varios autores sobre el comportamiento del protozoario en humanos y en animales de laboratorio así como los resultados descritos en este trabajo, plantean la posibilidad de que determinadas cepas de T. rangeli, en condiciones particulares, podrían causar alteraciones patológicas en el mamífero.

The method, site, and stage of multiplication of Trypanosoma (Herpetosoma) rangeli Tejera, 1920 has not hitherto been known. "We have now observed many intracellular nests or pseudocysts, containing amastigotes and trypomastigotes of this parasite in the heart, liver, and spleen of suckling (5.0 g) male white mice (NMRI strain) inoculated i.p. with 9 x 10(4) metatrypomastigotes/g body weight from a 12-day-old culture of the "Dog-82" strain of T. rangeli. At the peak of parasitemia (1.9 x 10(6) trypomastigotes/ml blood, 3 days post-inoculation) various tissues were taken for sectioning and staining. The heart was most intensely parasitized. The amastigotes were rounded or ellipsoidal, with a rounded nucleus and the kinetoplast in the form of a straight or curved bar; the average maximum diameter of 50 measured amastigotes was 4.2 p. Binary fission was seen in the nucleus and kinetoplast of some amastigotes; no blood trypomastigotes were seen in division. The above characteristics, as well as the location of the pseudocysts in the tissues, are similar to T. cruzi. Comparison of these results with those reported for other Herpetosoma suggest study of the taxonomic position of T. rangeli.

El método, sitio y estadio de multiplicación de Trypanosoma (Herpetosoma) rangeli Tejera, 1920 no había sido determinado hasta ahora. Nosotros hemos observado numerosos nidos o pseudoquistes intracelulares que contienen amastigotes y tripomastigotes de este parásito en el corazón, hígado y bazo de ratones albinos machos de 5,0 g de peso (cepa NMRI) inoculados por vía i.p. con 9,0 x 10(4) metatripomastigotes/g de repique de 12 días en medio LIT, cepa "Perro-82". En el pico de la parasitemia (1,9 x 10(6) tripomastigotes/ml de sangre, 3 días post-inoculación) fueron retirados varios órganos para seccionar y teñir con hematoxilina-eosina. El corazón fue el órgano mas intensamente parasitado. Los amastigotes son redondeados y ovalados, con núcleo redondeado y kinetoplasto en forma de barra recta o curva; el promedio del diámetro máximo de 50 amastigotes medidos fue de 4,2 m. Fue observada fisión binaria en el núcleo y kinetoplasto de algunos amastigotes; no fue vista división en los tripomastigotes sanguícolas. Las características anteriores, así como también la localización de los pseudoquistes en los tejidos, son similares a T. cruzi. La comparación de estos resultados con los reportados para otros Herpetosoma sugiere el estudio de la posición taxonómica de T. rangeli.