Prevalence and diagnostic approach for a neglected protozoon Blastocystis hominis

ObjectiveTo determine the prevalence of Blastocystis hominis (B. hominis) among pre-school children and evaluate the different staining techniques for its detection in stool.MethodsA total of 300 children of both sexes aged 2–5 years were included in this study. Each child was subjected to examination of stool sample using iodine, safranine methylene blue (SMB) and modified Ziehl-Neelsen (MZN) stains. Immunofluorescence antibody (IFA) stain was applied on stool specimens of 30 cases only.ResultsResults showed a total prevalence rate of 53%. A higher prevalence was detected among children aged 4–5 years and most of them were males. The majority of cases (82.8%) infected with Blastocystis alone were symptomatic. Fecal parasite burden was significantly higher in symptomatic than asymptomatic cases, so B. hominis should be considered as a pathogenic parasite. IFA stain was proved to be the most sensitive (73.3%) followed by MZN (68.2%), iodine (59.1%) and SMB (50%) stains.ConclusionsThis study confirmed the pathogenic potential of B. hominis and shed light on the great need to promote the hygienic standards among the risky group of children. IFA staining technique though having the highest sensitivity, it is suitable for use in large hospitals or public health laboratories in developed countries owing to its high cost. The MZN staining technique had a significantly higher sensitivity than iodine and SMB stains, and was more feasible to be used in laboratories with limited funds as in Egypt, because it is cheap, rapid, easy to perform and clarify the definitive morphological details of the parasite.