Effectiveness of Uv-Disinfection Against Cercaria at Selected Wavelegnth Using Uv-Leds (for Schistosomiasis Control)

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Addis Ababa University


Due to a lack of water and sanitation, schistosomiasis is a neglected tropical water-based chronic illness that kills. It is spread to people through contact with cercariae-infected water on the skin while bathing, swimming, or in any other way. In earlier research, various studies, including UV irradiation, have been conducted to eradicate the diseases-causing pathogenic parasite known as cerceriae. However no studies were carried out using the newly emerging UV-technology such as UV-LEDs. Hence the objective of this study was to investigate the effectiveness of UVC-LEDs (with a wavelength of 255nm, 265nm and 285nm) to disinfect Schsitosoma cercariae. Snails which an intermediate host for Schsitosoma cercariae were collected from Hawassa (Tikur Wiha River) and also from Lake Ziway. The collected snails were prepared for shading cercariae and 100-120 cercariea were prepare in 200μL. The disinfection of cercarea was examined using UVC-LEDs at a wavelength of 255 nm, 265 nm and 285 nm respectively. Using fluence (UV-dose) of 1 mJ/ cm2, 20 mJ/ cm2 ,40 mJ/ cm2, 60 mJ/ cm2, 80 mJ/ cm2, 100 mJ/ cm2, 120 mJ/ cm2,160 mJ/ cm2, 200 mJ/ cm2 and 300 mJ/ cm2. Under controlled settings, the experiment was repeated three times in a solution containing 200μL of cercariae-infested water and 3.6 ml of bottled water.All fluence (UV-dose) showed no significance cercariae disinfection at a wavelength of 255 nm. But Wavelengths 265 nm and 285 nm showed significance cercariae disinfection. 1 log reduction was achieved at a fluence of 300 mJ/ cm2 and wavelength of 265nm and 1.5 and 2 log reduction was achieved at fluence of 200 mJ/ cm2 and 300 mJ/ cm2 at wavelength of 285nm. It took 300 mJ/ cm2 fluence (UV-dose) to achieve 2 log reduction which is high compared to fluence used in different studies to disinfect other pathogenic parasite. Therefore, in this study UVC-LEDs used is a promising technology to disinfect schsitosoma cercariae but requires further studies. Therefore, more research and different methodology is needed to enhance its use and effectiveness.



Schistosomiasis, Cercariae, Fluence (UV-Dose), Disinfection, UV-Leds