Comparison between direct smear, formalin-ethyl acetate concentration, and Mini Parasep® Solvent-Free Concentrator for screening of intestinal parasitic infections among school-age children

Abstract

Background : Most patients infected with intestinal parasites are asymptomatic and usually undiagnosed. The sensitivity of stool examination by direct smear is quite low. Formalin-ethyl acetate concentration technique (FECT) is the method used to increase the sensitivity. However, FECT is considered to be a dangerous method because of the use of toxic solvent in the process. Mini Parasep® Solvent-Free (SF) Concentrator is a new diagnostic tool used as routine stool examination for parasitic infections in several countries worldwide.

Objective : To evaluate the efficacy of Mini Parasep® SF concentrator compared with the direct smear method and FECT for screening of intestinal parasitic infections in school-age children.

Research design : Cross-sectional study.

Setting : Nakhon Pathom and Chanthaburi provinces, Thailand.

Participants : Students in Wat Don Yai-Hom School (N = 265), Wat Burapha Phitthaya Ram School (N = 32), Ban Patong School (N = 181), Ban Wang I-Aen School (N = 46), and Wat Nam Khun School (N = 50)

Methods : Stool samples (N = 574) were examined for intestinal parasites by simple smear, FECT, and Mini Parasep®SF concentrators.

Results : Mini Parasep®SF showed the highest sensitivity for overall detection of intestinal parasitic infections (56.38%), followed by direct smear method (40.43%), and FECT (37.23%). Using these three methods, the overall prevalence of intestinal parasitic infections among students was 16.38%. While the prevalence in Nakhon Pathom Province was 18.49%, the prevalence in Chanthaburi Province was 14.56%. The most common parasite found was Blastocystis hominis (8.01%), followed by Giardia intestinalis (2.61%) and Entamoeba histolytica (0.87%). Moreover, non-pathogenic protozoa, including Entamoeba coli (1.05%), Endolimax nana (5.57%), Iodamoeba butschlii (0.17%), were also detected. However, only 4 students (0.70%) in Chanthaburi Province were infected with helminth infections, including hookworm (0.35% prevalence) and Opisthorchis viverrini (0.35%).

Conclusion : As the advantages of Mini Parasep®SF which include high sensitivity, closed system, safety, and rapidness, this method is a useful diagnostic technique, especially for screening of intestinal parasitic infections.