A strategy for emergency treatment of <it>Schistosoma japonicum</it>-infested water

• Main Authors: Li Hong-Jun, Xing Yun-Tian, Wang Wei, Liang You-Sheng, Xu Yong-Liang, Shen Xue-Hui, Qu Guo-Li, Li You-Zi, Dai Jian-Rong
• Format: Article
• Language: English
• Published: BMC 2011-11-01
• Series: Parasites & Vectors
• Subjects: Schistosomiasis japonica; <it>Schistosoma japonicum</it>; cercaria; suspension concentrate of niclosamide; emergence treatment; infested water; the Yangtze River
• Online Access: http://www.parasitesandvectors.com/content/4/1/209

<p>Abstract</p> <p>Background</p> <p>Schistosomiasis japonica, caused by contact with <it>Schistosoma japonicum </it>cercaria-infested water when washing, bathing or production, remains a major public-health concern in China. The purpose of the present study was to investigate the effect of a suspension concentrate of niclosamide (SCN) on killing cercaria of <it>S. japonicum </it>that float on the water surface, and its toxicity to fish, so as to establish an emergency-treatment intervention for rapidly killing cercaria and eliminating water infectivity.</p> <p>Results</p> <p>At 30 min after spraying 100 mg/L SCN, with niclosamide dosages of 0.01, 0.02, 0.03, 0.04 g/m², the water infectivity reduced significantly and no infectivity was found at 60 min after spraying SCN. The surface of static water was sprayed with 100 mg/L SCN, the peak concentration was found at 0 min, and the solution diffused to site with a water depth of 10 cm after 10 min. 30 min later, SCN diffused to the whole water body, and distributed evenly. After spraying 100 mg/L SCN onto the surface of the water with a volume of(3.14 × 20²×50)cm³, with niclosamide dosages of 0.02 g/m², 96 h later, no death of zebra fish was observed.</p> <p>Conclusions</p> <p>By spraying 100 mg/L SCN, with a niclosamide dosage of 0.02 g/m²onto the surface of <it>S. japonicum</it>-infested water, infectivity of the water can be eliminated after 30-60 min, and there is no evident toxicity to fish. This cercaria-killing method, as an emergency-treatment intervention for infested water, can be applied in those forecasting and early warning systems for schistosomiasis.</p>