The possible effects of pH and specific gravity on the ether-sedimentation procedure in concentrating eggs and cysts.

Abstract

Summary The effect of varied pH values (4, 7 and 10) on the diagnostic efficiency of the ether-sedimentation procedure has been investigated. Fertile Ascaris and Schistosoma japonicum eggs were recovered in greatest numbers with a pH value of 10, and were sufficiently reduced in number at pH 4 to adversely affect the diagnostic efficiency. Conversely, hookworm eggs were best recovered at pH 4 and 7, with almost complete loss at pH 10. Although whipworm eggs were most effectively recovered at pH 7, diagnostic efficiency was not appreciably affected by the pH variable. An attempt was also made to determine the effect of lowered specific gravity. Alcohol, to the extent of 20%, was introduced into each pH solution. The nature of the results suggested that the alcohol per se was an influence, but in all test solutions the numbers of Ascaris, whipworm and S. japonicum eggs were greatly increased, particularly at pH 7, while hookworm was little affected.