Diagnosis of Fasciola gigantica in snail using the polymerase chain reaction (PCR) assay.

Abstract

The 124-bp repetitive and highly abundant DNA sequence--used as a specific probe for the detection of Fasciola hepatica infection in snails--was tested in the detection of F. gigantica infection in Lymnaea natalensis. The probe did not show any positive PCR results with Lymnaea natalensis, Physa acuta, Biomphalaria alexandrina and Bulinus trucatus or with Schistosoma mansoni, S. haematobium and Echinostoma liei. However, the probe was found capable to detect F. gigantica infection within L. natalensis at very early stages of the prepatent period and at very low concentrations. Thus, the present assay is specific and sensitive for the detection of F. gigantica within its intermediate host. It confirmed the idea that 124-bp repetitive and highly abundant DNA sequence in Fasciola sp. genome could be used as an epidmiological tool for examination of fasciolosis intermediate host. The nucleic acid-based assay could eliminate both inherent uncertainties and lengthy periods of time required for visual examination of the snails. Also, the assay is valuable in epizootiology of F. gigantica, vector suitability and host-parasite relationship.