ScienceAsia 19 (1993): 117-128 |doi: 10.2306/scienceasia1513-1874.1993.19.117

EFFECTS OF NICLOSAMIDE AND EUCALYPTUS CAMALDULENSIS ON BIOMPHALARIA GLABRATA, THE SNAIL INTERMEDIATE HOST OF SCHISTOSOMA MANSONI

XIAONONG ZHOU,^a E.SUCHART UPATHAM,^b MALEEYA KRUATRACHUE^b AND PRAPEE SRETARUGSA^c

ABSTRACT: Toxicity studies were carried out on the snail Biomphalaria glabrata using niclosamide (bayluscide) and the extract from dried leaves of Eucalyptus camaldulensis. The snails were exposed to Niclosamide and to aqueous and methanolic extracts of E. camaldulensis for 24 h and recovered for 48 h. In niclosamide, the LC₅₀ and LC₉₀ values were 0.063 and 0.126 mg/l, respectively. In aqueous extract, the LC₅₀ and LC₉₀ values were 3049.65 and 5568.33 mg/l; while in methanolic extract, they were 71.59 and 96.73 mg/l. Histological changes were observed in the intestines, digestive glands and ovotestes of the molluscicides treated snails. In the intestines, gaps were formed between the epithelial cells and the connective tissue resulting in the derangement of the ciliated cells. In the digestive glands, the digestive cells became irregular in shape; and both digestive and calcium cells showed considerable shrinkage. The ovotestes of the molluscicides treated snails showed reduction in numbers of spermatozoa and oocytes.

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Received August 7, 1993