Experimental Measurement of Specific Gravity of Oncomelania hupensis and Its Eggs

Abstract

To understand the distribution of Oncomelania hupensis, the intermediate host of Schistosomiasis japonicum, the specific gravities of the snails and their eggs must be known. When the specific gravities are known, the snail and its egg drop speed can be calculated and drift distance can be deduced in the river. The measurement of specific gravities of snails and eggs was carried out in accordance with the routine measures of specific gravity of river silt in China. The results indicated an average specific gravity for the live snails of 1.80 ± 0.01 g/cm³, and for snail eggs of 2.29±0.01 g/cm³. The measured value of the specific gravity for the snails and its eggs must be considered when water condervancy facilities are disigned and/or rebuilt for prevention of the spread of snails in the endemic area of schistosomiasis.