Indirect haemagglutination versus direct methods in diagnosis of mansonmsis

ABSTRACT

The aim of the present work was to evaluate some laboratory parasitological and serological methods used in the diagnosis of S. mansoni infection. These methods were direct smear method, Kato-thick smear and modified Ritchie formal-ether concentration technique. The serological method used was the indirect hemagglutination test. Sixteen healthy children negative for parasitic infections were taken as control. 39 children presenting with acute or chronic intestinal schistosomiasis, their age ranged from 7 to 12 years with a mean of 9.6. Stool analysis by Kato-thick smear gave 60% positivity in group 1 [acute schistosomiasis], i.e. 14 out of 23 patients, and 25% positivity in group 2 [chronic cases], i.e. 4 out of 16 patients. Stool analysis by the Ritchie formal-ether concentration technique gave 82% positivity in the first group [19 out of 23 patients] and 37% in group 2 [6 out of 16 patients]. The indirect hemagglutination test gave 95% positive in group 1 [22 out of 23 patients] and 87% in group 2 [14 out of 16 patients]. Out of all patients examined [39], 18 [46%] were positive by Kato-test, 25 [64%] were positive by Ritchie test and 36 [92%] by indirect hemagglutination test. All control subjects were negative by the 3 tests used. From results, it could be concluded that the Ritchie method is more sensitive than Kato test in detection of eggs of Schistosoma mansoni in stools. Also, the indirect hemagglutination test seemed to be both sensitive and specific