Ovicidal Activity of Disinfectants against Enterobius vermicularis Eggs: Evaluation Using a Staining Technique

Introduction: Enterobiasis is one of the most common helminthiasis, especially among children. One of the reasons for the formation of foci of enterobiasis in children’s facilities is the ability of parasite eggs to remain viable on environmental objects, thereby maintaining the risk of infection.

Objective: To study the efficacy of disinfectants against E. vermicularis eggs with the determination of their viability by staining.

Materials and Methods: We took eggs of 15 E. vermicularis females for testing to determine the viability of pinworm eggs by means of staining with methylene blue in a lactic acid solution with caustic alkali. Within the experiment, we evaluated the efficacy of two chlorine-based disinfectants in a working dilution of 0.60 %, the active ingredient of which was the dichloroisocyanuric acid sodium salt (NaDCC 75.8 % and 84 %), against pinworm eggs. The results are presented as absolute values and percentages; comparisons were made using the Pearson’s χ² test. Differences were considered statistically significant at p < 0.05.

Results: We observed high ovicidal activity of the disinfectants tested. The disinfectant containing 75.8 % of sodium salt of dichloroisocyanuric acid as the active substance showed a pronounced effect with the death of 86.3 % and 62 % of pinworm eggs when added to the suspension and applied to the surface, respectively, while the disinfectant containing 84 % of the same active substance demonstrated the efficacy 84.4 % and 82.9 %. We also established that five minutes is the optimal time for E. vermicularis egg staining using a methylene blue working solution.

Conclusions: Methylene blue staining and determination of the optimal staining time for pinworm eggs helped evaluate the ovicidal efficacy of disinfectants. Analysis of the results revealed significant differences in the ratio of viable and nonviable E. vermicularis eggs between the samples treated with the disinfectants and their controls.

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