Morphological and molecular characterization of Lecithochirium grandiporum (Digenea: Hemiuridae) infecting the European eel Anguilla anguilla as a new host record in Egypt

Abstract

In the present study, the morphological and molecular characterization of Lecithochirium grandiporum, a digenetic trematode infecting the European eel Anguilla anguilla (Family (F): Anguillidae), were described for the first time from Burullus Lake, Kafr El-Sheikh Governorate, Egypt. Twenty-five out of 60 specimens (infection rate of 41.66%) were found to be naturally infected. Infection was recorded as small worms attached to the inner wall of the intestine of host fish. Adult worms measured 1.59 ± 0.20 (1.3-1.85) mm long and 0.3 ± 0.02 (0.29-0.48) mm wide for everted specimens with a smaller oral sucker measuring 0.15 ± 0.02 (0.13-0.18) mm, and a larger ventral sucker which was 0.16 ± 0.02 (0.14-0.25) mm. Our results recorded morphological differences as smaller dimensions of different body parts and the smaller oral/ventral sucker ratio between Lecithochirium fusiforme and L. grandiporum. Also, the phylogenetic position of the worm was determined by molecular characterization of their 18 SSU rDNA. Results were compared with those of previously recorded species on the Gene Bank. It was found that the present species coincide with those belonging to genus Lecithochirium. Comparison of the nucleotide sequences and divergence showed that the SSU rDNA gene of this Lecithochirium species revealed 92 % sequence identity with L. fusiforme (accession no. DQ413192) differing in 26 nucleotides with lower divergence value. According to these results, this study indicated that the present species is recorded as L. grandiporum with accession no. KC166146 as a parasite with new host and locality records in Egypt.