Morphometric phenotypes and molecular identification of Fasciola species isolated from cattle in Ilorin, North-Central Nigeria

Abstract

Fascioliasis is a serious infectious parasitic disease of human and domestic ruminants. It is caused by the common liver flukes Fasciola hepatica and Fasciola gigantic and it is of public health concern in some countries of the world. Species-level identification of these species using only morphological methods is unconvincing, unreliable and sometimes difficult. Molecular methods enhance the prospects of species-level identifications using a well established and highly reliable DNA-based approach. We used PCR-RFLP analysis for precise identification of Fasciola species collected from Nigeria. One hundred Fasciola adult worms were collected from selected abattoirs in Ilorin, North-central Nigeria. The parasitic worms were first identified by morphometric analysis using AmScope digital camera fastened to the ocular eye piece of the light microscope. For the molecular identifications, genomic DNA was extracted, Polymerase Chain Reaction (PCR) technique and RFLP were used to characterise the Fasciola adult worms. Morphometric data showed that 70 out of the 100 Fasciola adult worms have characteristic features similar with that of F. gigantica as described from previous studies while the remaining 30 adult worms have characteristics that deviate from that of F. gigantica but did not confirm with characteristic features of F. hepatica. Agarose gel electrophoresis result confirmed successful amplification of two gene regions of Sodium Dehydrogenase I (ND1) from mitochondrial DNA of Fasciola spp. The PCR-RFLP analysis did not show any noticeable genetic variation in the Fasciola adult worms. We suggest more studies to be done using DNA sequence analysis and other molecular markers such as random amplified polymorphic DNA (RAPD) and simple sequence repeat (SSR) to better understand the genetic variability and population structure within Fasciola spp. in Nigeria.