Molecular and Taxonomical Studies on the Amphistomes Infecting Ruminants in Saudi Arabia

Abstract

Amphistomes are digenetic trematodes; infecting ruminants include sheep and cattle in Taif, Saudi Arabia causes amphistomiasis. The infection rate by amphistomiasis was investigated at different local abattoirs in Taif Governorate. The infection rate was 12/120 (10%) in cattle while was 15/1500 (1%) in sheep. The collected flukes were classified into three groups. First group was prepared for Light Microscope investigation while the second group of flukes was prepared for investigation by scanning electron microscopy (SEM). The last group was fixed for further molecular processes. Five species of amphistomes were preliminary morphologically identified; two of them belong to (unpouched amphistomes), subfamily Paramphistominae, family Paramphistomidae; named as Calicophoron clavula & Calicophoron microbothrium. The other three species belong to (pouched amphistomes) of two genera; the first genus; Carmyerius includes two species; Carmyerius exoporus & Carmyerius gregarius while the second genus Gastrothylax includes the last species (Gastrothylax crumenifer). The above three species belong to subfamily Gastrothylacinae, Family Gastrothylacidae. The morphological identification is not sufficient due to high similarity of species and the thick body of amphistomes. The molecular analysis was applied to confirm the morphological identification of amphistomoid species. Genomic DNA was extracted from the collected specimens and investigated utilizing definite regions of ribosomal DNA (rDNA) annotated as the second internal transcribed spacer (ITS2). PCR-based diagnosis was used to identify digenean species and to construct their phylogenetic relationships by using Molecular Evolutionary Genetics Analysis (MEGA-X) program. The integration