Is the Baermann, an applicable method for detection of Strongyloides stercoralis?

Introduction: It is estimated that 100 - 300 million people in the world are infected with Strongyloides stercoralis. Although there are several laboratory diagnostic methods for detection of this parasite, there is still no gold standard diagnostic method. The need for an application test with high sensitivity and specificity is highly felt, especially in people with immune deficiency or organ transplant volunteers. Methods: The diagnostic sensitivity of five parasitological methods, including direct smear of feces in saline and Lugol iodine stain, Baermann technique, formalin-ethyl acetate concentration, Harada-Mori filter paper, agar plate culture and molecular method was evaluated by stool specimens collected from the central mentally retardation institute of Bandar Abbas, to find out an easy, practical and cost-effective method for detecting Strongyloides stercoralis. Results: Five parasitological and molecular methods were investigated using 163 stool samples. Considering the employed methods, there found to be 30 cases of S. stercoralis. The total positive cases of S. stercoralis using different methods was considered as golden standard. The highest sensitivity of parasitological methods was associated with the Baermann 27 (90%) and the least positive results obtained with Harada-Mori method, 1 (3.3%). In this study 9 positive cases were detected by PCR method (30%). Conclusion: Highest sensitivity was observed when different diagnostic approaches were combined where Baermann technique proceeded it. Therefore, this technique is recommended as a selective method for detecting S. stercoralis due to its easy, practical and inexpensive nature.