Cao Q, Gu B L, Hang M D, He S Y
Jiangsu Institute of Parasitic Diseases, wuxi.
Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi. 1992;10(4):255-7.
Field observation on the population fluctuation of Oncomelana snail at low density was carried out in the ditches and rivers in Wuxi, Ludong and Lugao counties (or city) from 1987 to 1990. The results showed that the environment of the observed places is an important factor in the population fluctuation of the snails at low density. When the environment is appropriate, even one pair of the snails may multiply to a large population. Results of successive observation for 3 years on 1, 5 and 10 pairs of snails within nylon cages in ditches showed that the density of the snails increased by 171.5, 69.5 and 28.4 folds respectively and the population of the snails increased by 354, 135 and 75 folds respectively. The population in 2 of the observed ditches with one pair of snails each even multiply by 543 and 426.5 folds. While in natural field condition, the population fluctuation of residual snails varied in different places. In one ditch it multiplied by 34.7 folds, but in another river the population almost unchanged. No natural elimination of snails could be found in all observed places. It was suggested that the snail surveillance should be conducted persistently and any snail once be found, it should be timely eradicated.
1987年至1990年，在无锡、如东和如皋县（市）的沟渠和河流中，对低密度钉螺种群数量波动进行了实地观察。结果表明，观察地点的环境是低密度钉螺种群数量波动的一个重要因素。当环境适宜时，即使一对钉螺也可能繁殖成大量种群。对沟渠中尼龙笼内1对、5对和10对钉螺连续3年的观察结果表明，钉螺密度分别增加了171.5倍、69.5倍和28.4倍，钉螺种群数量分别增加了354倍、135倍和75倍。观察的2条沟渠中，每条沟渠有1对钉螺，其种群数量甚至分别增加了543倍和426.5倍。而在自然野外条件下，残留钉螺的种群数量波动在不同地点有所不同。在一条沟渠中，其数量增加了34.7倍，但在另一条河流中，种群数量几乎没有变化。在所有观察地点均未发现钉螺的自然消亡情况。建议持续开展钉螺监测，一旦发现钉螺，应及时消灭。
