Filtration, centrifugation and mouse exposure for the detection of schistosome cercariae in water

ABSTRACT

Three methods for the detection of Schistosome cercariae in water were studied under laboratory and simulated field conditions in Egypt. Water samples tested by filtration and centrifugation, quantitatively, reflected the density of cercariae in moderately turbid canal water [30 nephelometry Turbidity Unites, NTU]. When tested in waters of increasing turbidity, the centrifuge gave more consistent results than the filtration system. The centrifugation technique was more efficient in processing the water samples and took almost half the time of filtration and mouse exposure was useful in detecting cercariae, but was not quantitative. However, there was a significant improvement in worm recovery when mice were more close together in the floatation device. Mouse exposure was also expensive and cumbersome to use. The present results concluded that centrifugation may be considered the technique of choice for further cercariometric work under the Egyptian conditions