Rearing of Lymnaea columella (Say, 1817), intermediate host of Fasciola hepatica (Linnaeus, 1758)

The intermediate host of Fasciola hepatica, Lymnaea columella, collected in Belo Horizonte, Minas Gerais, Brazil, was reared in our laboratory. The aim of the current study was to standardize a rearing and maintenance technique. Two kinds of diet were tested: fresh lettuce (A) and rodent ration + 10 percent CaCO3 plus fresh lettuce (B). The age for the beginning of oviposition ranged from 27 to 57 days. Ten days after oviposition at 24.7§C, 100 percent eclosion occurred. The complete life cycle varied from 37 to 67 days. The average numbers of eggs per egg mass were 26.3 and 31.1 with diets (A) and (B), respectively. The lettuce and ration fed snails presented a increased growth although the difference was not statistically significant (p > 0.05). The mortality rate varied from 40 to 64 percent after 90 days. The maximum longevity was 183 days, 21.5 mm length and 11 mm wide. The methodology to mass breed and maintain these snails was found to be suitable in the laboratory.

Natural infection of trematodes in Lymnaea (Radix) auricularia rubiginosa in water reservoirs in Amphoe Muang, Khon Kaen Province.

Lymnaea (Radix) auricularia rubiginosa (Michelin, 1831) was surveyed in 54 reservoirs of 18 districts in Amphoe Muang, Khon Kaen Province during February to May 1994. Lymnaeid snails were found in the water of 20 reservoirs, of which 16 reservoirs contained clear water and 4 turbid water. Two of the four turbid water reservoirs received drainage water from Khon Kaen Town. Two thousand four hundred and eight L. auricularia rubiginosa were collected and examined by shedding and crushing. Trematode infection occurred in 163 (6.77%) of 2,408 L. auricularia rubiginosa and some snails were infected with more than one cercarial species. Ninety-nine snails (4.11%) were infected with echinostomes, while mixed infection of echinostomes with Fasciola gigantica and with schistosomes was found in 5 snails (0.21%) and 2 snails (0.08%), respectively. Only 1 snail (0.04%), 19 snails (0.79%) and 37 snails (1.54%) were infected with F. gigantica, schistosomes and unidentified species, respectively. The mean size of infected snails was 6.89 +/- 2.02 mm (6.20-22.36) while the mean of sampled snails was 13.46 +/- 3.64 mm (4.00-26.55). The water plants which were found in reservoirs and presented with snails, were creeping water primose (Jusstaea repens), water lily (Nymphaea sp), water hyacinths (Eichornia crassipes) and grass.

Ocorrência de Lymnaea columella (Say, 1817)(Mollusca, Pulmonata, Lymnaeidae), no Estado de Goiás. Consideraçöes sobre os parasitos por ela transmitidos / Occurrence of Lymnaea columella (Say, 1817)(Mollusca, Pulmonata, Lymnaeidae) in the State of Goiás and commentes about the ralationships of the molluc with the transmission of some parasites

Os autores relatam a primeira ocorrência de Lymnaea columella (Say, 1817) no Estado de Goiás, ressaltando a importância da espécie como hospedeiro intermediário de vários parasitos dos animais domésticos, dos quais, alguns são agentes de zoonoses no Brasil e em outros países. Também fazem considerações sobre os parasitos transmitidos ou possivelmente transmitidos por este molusco, já assinalados no Brasil

Estadísticas vitales de Lymnaea cubensis (Pfeiffer, 1839) en condiciones de laboratorio / Vital statistics of Lymnaea cubensis (Pfeiffer, 1839) under laboratory conditions

Cuatro cohortes de L. cubensis fueron cultivadas en condiciones de laboratorio y se estimaron las siguientes estadísticas vitales y parámetros demográficos: longevidad máxima promedio = 207 días, primera edad de reproducción = 57 días, duración del desarrollo embrionario = 8 días, tamaño del huevo = 0,69 mm x 0,58 mm, número de huevos por masa = 13, producción total de masas de huevo durante la vida adulta = 80, producción total de huevos durante la vida adulta = 1.060, tiempo generacional = 130 días, tasa de reemplazo = 241 y tasa intrínseca de crecimiento natural = 0,036 días. El valor reproductivo ponderado alcanza sus mayores valores entre las edades de 0 y 30 días. Entre las cohortes no se encontraron diferencias significativas en lo que se refiere a sobrevivencia, pero si respecto a fecundidad (número de huevos producidos por caracol)