Evaluation of the Kato thick smear technique for epidemiological surveys in areas with low schistosoma mansoni endemicity

The Kato quantitative method for stool examination is recommended for epidemiological surveys on S.mansoni. The end point of sensitivity of this method was considered 20 eggs/gm. The present work aimed at evaluating this technique in areas of low endemicity. Random samples were collected from three villages with S. mansoni prevalence 9-14.4% and in which 90% of patients had low counts. Each sample was processed by Kato [2 slides], modified Ritchie formol-ether and saline sedimentation. The Kato technique was found 2.5-5 times more sensitive than the other two methods. It diagnosed 71.4% of the total number of cases diagnosed by the three methods collectively. The formol-ether diagnosed only 14-28% of cases and simple sedimentation 14-21%. It is concluded that the Kato quantitative method is recommended for determination of prevalence in areas with low S. mansoni endemicity; however 30% of cases may still be missed

Effect of polyclonal B-lymphocyte activation and Schistosoma mansoni infection on splenic B-glucuronidase enzyme in mice

The effect of stimulation of spleen cells on the B-glucuronidase [BG] activity, in mice was investigated. The study was performed on 4 groups of mice: LPS group [150 micro g/mice], Schistosoma mansoni group, LPS and S.mansoni and control group. In the LPS group the maximum increase in BG activity was observed after one week of infection; it dropped to the normal level after two weeks and remained so till the fourth week. In the S.mansoni group, the maximum BG activity was obtained after one week of infection; it gradually decreased in the subsequent weeks, but remained at levels significantly higher than normal. In the LPS and S.mansoni group, the levels of the BG activity were similar to those of the LPS group except that after four weeks, the activity became significantly higher than the normal level. The relative changes in B-lymphocytes in the spleen [as demonstrated by immunofluorescent technique] were in agreement with BG findings. It could be concluded that activation of BC enzyme after stimulation of immunocompetent cells is a consequence of their proliferation and is not antigen specific. This can be a part of the host defence against offending pathogens