Behavioral and hormonal changes associated with the infective dose in experimental taeniasis in golden hamsters (Mesocricetus auratus).

INTRODUCTION: It has been reported that behavioral changes relate to infection in different parasitoses. However, the relation between the extent of the behavioral changes and the magnitude of the infection has been scarcely studied. The aim of this study was to evaluate the relationship between different doses of infection and the behavioral changes induced in the experimental Taenia pisiformis taeniasis in golden hamsters. METHODS: Groups of nine hamsters were infected with three or six T. pisiformis metacestodes. The locomotor activity was quantified daily in an open field test during the 21 days after infection; anxiety test was performed in an elevated plus-maze with a dark/light area at 7, 14 and 21 days post-infection, and serum cortisol levels were determined by radioimmunoassay before infection and at day 22 after infection. RESULTS: The challenge itself induced modifications on behavior and cortisol levels in hamsters, with or without successful infection (taenia development). Animals challenged with three metacestodes induced a decrease in locomotor activity and an increase in anxiety in infected animals. A higher and earlier decrease in locomotor activity and increased anxiety levels were observed in hamsters challenged with six cysticerci, which were accompanied by higher levels of sera cortisol at the end of the experiment. At necropsy, 44-55% of hamster became infected with an efficiency of implantation of 22-26%, challenged with three or six cysticerci respectively. CONCLUSION: The challenge of hamsters with metacestodes, promote behavioral changes in an extent dependent on the magnitude of the challenge, disregarding the effectiveness of the infection.

Citología y análisis morfométrico de las células del epitelio vaginal durante el ciclo estral en ovejas de pelo (Ovis aries) / Citology and morphometric analysis of epithelial cells from the vagina of hair sheep ewes (Ovis aries) during their estrous cycle

La citología vaginal puede usarse para caracterizar estados del ciclo reproductivo de la hembra. Sin embargo, no ha sido validada en ovinos de pelo, y ofrece resultados inexactos debido a interpretaciones subjetivas. El objetivo del presente trabajo es tipificar las características morfológicas y morfométricas de las células epiteliales de la vagina durante el ciclo estral en ovinos de pelo. Cinco borregas Santa Cruz se sincronizaron con esponjas intravaginales. Desde el día del 1er celo posterior al retiro de la esponja y hasta el siguiente celo, se obtuvieron muestras diarias del epitelio vaginal de cada oveja, y se cuantificó el número de células parabasales, intermedias y superficiales, y se midió la longitud, perímetro y área de citoplasma y núcleo de cada una. Los resultados muestran que las células superficiales incrementan (P<0,05) durante el estro en comparación con el diestro. En contraste, el número de células parabasales e intermedias es mayor (P<0,05) durante el diestro que en el estro. Las células más grandes (36,11+/-0,38 µm) y núcleos más pequeños (8,46+/-0,12 µm) se encontraron durante el estro, independientemente del tipo de célula, mientras que citoplasmas más pequeños (26,72+/-0,11 µm) y núcleos más grandes (10,48+/-0,02 µm) se observaron durante el diestro. Se concluye que la morfología de las células epiteliales de la vagina de la oveja de pelo coincide con las variaciones encontradas en otras hembras, y que el tamaño de citoplasmas y núcleos presenta un patrón cíclico que puede utilizarse para determinar de manera objetiva la etapa del ciclo estral de la oveja.

Vaginal cytology can be used to characterize stages of the reproductive cycle of the female. However, it has not been validated in hair sheep, and generates inaccurate results due to subjective interpretations. Thus, the purpose of the present work is to typify morphologic and morphometric characteristics of the epithelial cells from the vagina during the estrous cycle of hair sheep. Five Saint Croix ewes were synchronized with intravaginal sponges. Day zero of the cycle was considered the day of first estrus after sponge withdrawal. From this day until next estrus, samples from the vaginal epithelium were obtained daily from each ewe. The number of basal, intermediate and superficial cells was quantified, and length, perimeter, and area from cytoplasm and nucleus were obtained. The results show that the number of superficial cells increase (P<0.05) during estrus and decrease during the rest of the cycle. In contrast, the number of basal and intermediate cells showed an inverse pattern. The largest cells (36.11+/-0.38 µm) and smallest nucleuses (8.46+/-0.12 µm) were present during estrus, regardless of the cell type, while the smallest cells (26.72+/-0.11 µm) and larger nucleuses (10.48+/-0.02 µm) were observed during diestrus. It was concluded that citology of the epithelial cells from the vagina of hair ewes is in accord with changes found in other female spices, and that cytoplasm and nucleus sizes display a cyclic pattern that might be used to objectively determine the specific estrous cycle phase of the ewes.