Molecular characterization of Fasciola gigantica infecting cattle in Benin City, southern Nigeria, based on LSU and ITS1 ribosomal DNA sequences

Abstract

Fasciola gigantica is the widely reported aetiological agent of fascioliasis in bovines and ovines in Nigeria. Prior to this investigation there has not been any molecular confirmation of the Fasciola species infecting livestock in the country. Fasciolid flukes isolated from livers of two cows from an abattoir in Benin City, Edo State, were characterized by sequencing the partial fragment of the large subunit ribosomal nuclear DNA (LSU rDNA) and the first internal transcribed spacer region (ITS1). Phylogenetic analysis based on Maximum Likelihood show a close relationship between the novel sequences from this investigation with F. gigantica sequences from different countries in Africa (p-distance: 0.000, ITS1; 0.000 and 0.002, LSU). Comparison of p-distance reveal that the sequences within the F. gigantica clade diverge from its sister species F. hepatica by values ranging between 0.008-0.015 for LSU rDNA while the values for the ITS1 was 0.010 or 0.011. The novel sequences in this study are the first for F. gigantica from cattle in Nigeria and thus serves as baseline data for molecular identification of the species in the country.

Keywords: Fasciola gigantica; DNA sequences; cattle; Benin City; Nigeria