Use of Kato and nucleopore techniques for qualitative diagnosis of schistosomiasis

A comparison on qualitative basis, is attempted between merthiolate-iodine-formaldehyde concentration (MIFC) and Kato thick smear techniques for diagnosis of schistosome eggs in stools. As well, the centrifugation-sedimentation method was compared with the Nucleopore filtration technique for schistosome eggs in urine. Using MIFC and Kato techniques, 149 out of 185 subjects were found to have Schistosoma mansoni infection, 41 of them were diagnosed by Kato alone, while no case was solely MIFC positive. The sensitivity of MIFC compared to kato was 72.3% and both techniques were 100% specific. For diagnosis of S. haematobium infection, 78 out of 103 subjects were positive by centrifugation- sedimentation and/or Nucleopore techniques. 42 of them were diagnosed by Nucleopore alone and none was positive by centrifugation- sedimentation only. The sensitivity of the latter technique was 46.2% and both techniques were 100% specific. The study demonstrates that Kato thick smear and Nucleopore filtration are highly sensitive techniques that can be used for routine qualitative diagnosis of schistosomiasis. Under field conditions, they are qualitatively and quantitatively useful. The Kato technique besides its high sensitivity is very cheap. The only limitation for the Nucleopore technique is its relative high expenses.