Kato-Katz technique, the quantitative stool examination is generally recommended for diagnosis and evaluation of Schistosoma mansoni infections by schistosome experts. Regarding the fact that Kato-Katz is known to be less sensitive in low to moderate infections, but in high endemic areas it was proposed to be more sensitive. The current study was conducted in order to re-evaluate the usefulness of the Kato-Katz technique in the diagnosis of schistosomiasis mansoni in high endemic area in central Sudan. 214 schoolchildren (124 boys and 90 girls) with age ranges from 10 to 16 years were enrolled in the study during the period from August 2014 to January 2015. Stool and blood samples were collected from all participants and subjected to variable tests of triple Kato-Katz thick smears, indirect haemagglutination test (IHT) and enzyme-linked immunosorbent assay (ELISA). The results revealed that, 38 (30.4%) samples were positive by the three applied techniques while 89 (41.4%) samples were negative. 45 (21 %) stool samples were positive by Kato Katz, and 69 (32.2%) samples were positive by both ELISA and IHA. On the other hand, 31 (14.4%) samples showed positive by IHA and ELISA but negative by Kato-Katz. Based on Kato-Katz technique as standard method, the sensitivity of ELISA was 93.3% compared to 84.4% for IHA, while the specificity of the two tests were 53.8% and 80% for ELISA and IHA respectively.
The study concluded that, even in high prevalence setting the Kato-Kats technique is remaining less sensitive in evaluating S. mansoni infection. Moreover, the combination of ELISA and IHA tests might be preferred to give more positive results in order to improve the diagnosis and to assist in the control of schistosomiasis.
Kato-Katz, Schistosoma mansoni, ELISA, IHA