Idalia Valerio

Two New Eimeria Spp. (Apicomplexa: Eimeriidae) from the Dusky Rice Rat, Melanomys caliginosus, Tome 1860, in Costa Rica

Abstract:  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.

Primer hallazgo de Spirometra mansoni en Felis domesticus de Costa Rica

fue sugerido en 1929 porFaust, Campbel y Kellog como Subgenero, paraincluir diphillobothrideos con el utero espiraladoy amontonado y huevecillos con extremosaguzados, posteriormente Mueller lo eleva a genero.Existen varias especies asociadas a este generopresentes en el hemisferio oriental tales como

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

Abstract:  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, M1–M3, respectively, had 8–15 (m1), 4–9 (m2), and 22–30 (m3) merozoites. Macrogametocytes and microgametocytes, as well as macrogametes and microgametes, completed the sexual cycle, finishing with the formation of unsporulated oocysts. This parasites 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.

Heterogeneidad en la metaciclogénesis in vitro de clones derivados de una cepa costarricense de Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae)

The in vitro metacyclogenesis was evaluated in three clones derived from the Costa Rican TC-4 strain of Trypanosoma cruzi as a criterion of biological heterogenity between clones and their parental strain. The clones were obtained from colonies that resulted from culturing the T. cruzi strain in 40% blood agar. These clones were named TC-4 α, TC-4 β, and TC-4 π and were maintained in diphasic 40% blood agar with 3,7% brain hearth infusion as the liquid phase. The metacyclogenesis was induced by incubating epimastigotes in triatomine artificial urine suplemented with proline (TAU + P) at a constant temperature (27oC). The progress in the metacyclogenesis was monitored daily and the ratio of metacyclic trypomastigotes/epimastigotes, the percent of trypomastigotes, and the concentration of metacyclic trypomastigotes (MT/mL) were determined. Variability was evaluated using ANOVA tests for repeated measures (α: 0,05). The indicators of metacylogenesis showed the highest values between 72 and 96 hours after the beginning of the experiment. In this interval there were significant statistical differences between some of the cellular systems (p < 0,05). These observations could suggest that the clonal composition of each strain of T. cruzi can determine the infectivity for the vertebrate host.

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

Abstract 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 parasites 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

Abstract 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 parasites endogenous development produced severe intestinal lesions in experimentally infected dusky rice rats.