Amato S B, De Rezende H E, Gomes D C, Da Serra Freire N M
Vet Parasitol. 1986 Dec;22(3-4):275-84. doi: 10.1016/0304-4017(86)90115-9.
The study revealed that although Lymnaea columella and Stenophysa marmorata were found in the same habitat, only L. columella harbored intramolluscan stages of F. hepatica. The population density of L. columella cyclically decreased between September and February, and increased from March to September. The drought that occurred between June and November 1981 dramatically reduced the number of snails collected. Larger snails were collected in March-July and November-December, while the smaller snails were collected in January-February and August-October, suggesting that there may be two generations of L. columella per year. The highest prevalence levels of infection in L. columella were: first year, June 8.82%, September 9.09% and October 10.52%; second year, March 6.25% and April 6.89%; third year, July 7.69%, August 10.25%, April 17.91% and May 13.91%. Results obtained with tracer sheep showed that the largest numbers of metacercariae were on pasture between June and October, and between March and April, but the infection was present during most of the year.
该研究表明，尽管在同一栖息地发现了柱椎实螺和大理石窄口螺，但只有柱椎实螺体内携带着肝片吸虫的软体动物内阶段。柱椎实螺的种群密度在9月至2月间呈周期性下降，3月至9月间上升。1981年6月至11月间发生的干旱极大地减少了采集到的蜗牛数量。3月至7月以及11月至12月采集到的蜗牛较大，而1月至2月以及8月至10月采集到的蜗牛较小，这表明柱椎实螺可能每年有两代。柱椎实螺的最高感染率为：第一年，6月8.82%、9月9.09%、10月10.52%；第二年，3月6.25%、4月6.89%；第三年，7月7.69%、8月10.25%、4月17.91%、5月13.91%。对追踪绵羊的检测结果表明，6月至10月以及3月至4月间牧场上的囊蚴数量最多，但一年中的大部分时间都有感染情况。
