抄録
Several series of bench scale experiments were performed to evaluate the usefulness of well established sucrose flotation techniques for separation of Cryptosporidium oocysts from water samples under the various conditions.
Firstly, fresh (one month old) and aged (36 month old) oocysts of C. parvum were spiked into distilled water and separated by the modified sucrose flotation technique or by the discontinuous sucrose gradients. The mean recovery rate of fresh oocysts by the modified sucrose flotation technique was higher (87.2%) than by the discontinuous sucrose gradients (68.4%). In contrast, the mean recovery rates of aged oocysts by two methods were significantly lower. The recovery rate using different initial concentration of oocysts showed no significant differences in recovery between each of them. The usefulness of the modified sucrose flotation technique for the separation of oocysts from raw water samples was also evaluated. The recovery rate of oocysts from low and moderate turbidity water (ntu=0.8 and 15.4) was nearly 80%, however the recovery rate from high turbidity water (ntu=350) was significantly lower (60.7%).
From these results we assume that the modified sucrose flotation technique is still useful as a fast one-step, simple to perform and inexpensive method for the separation of Cryptosporidium oocysts in environmental water samples.
