First detection and molecular characterization of Dientamoeba fragilis in cattle

Abstract

Dientamoeba fragilis is a agellated protozoan with amoeba-like morphology that inhabits the human gastrointestinal tract. It is endemic in a vast geography around the world, including developed countries. There are limited studies on non-human hosts of the parasite, and suitable hosts have not been clari ed.The parasite has been detected in non-human primates, pigs, cats, dogs, and rats. There is no study in the literature investigating and detecting the presence of this parasite in cattle.In the present study, stool samples taken from 128 different cattle and calves from 11 different farms between March 2017 and February 2020 were examined for the detection of D. fragilis via PCR. The isolates with the expected amplicon size were sequenced using the 18S ribosomal RNA region, and their genotypes were determined by BLAST analysis. Sequences were analyzed with the most similar and reference sequences in the literature, forming a phylogenetic tree.We detected D. fragilis in 26 (20.31%) of the 128 stool samples. All PCR products selected for molecular analysis from positive samples had the same nucleotide sequence. As a result of BLAST analysis, all sequences were determined to belong to D. fragilis genotype 1.This study determined for the rst time that cattle are suitable hosts for D. fragilis. Furthermore, the parasite subtype we detected belongs to genotype 1, which is the most common type in humans, suggesting that the parasite may have a zoonotic character. Our result is important in terms of the epidemiology of the parasite, as the mode of transmission is controversial, and available data on its natural hosts are limited.

A Cross-Sectional Study on the Occurrence of the Intestinal Protist, Dientamoeba fragilis, in the Gut-Healthy Volunteers and Their Animals

“…Dientamoeba was detected in eight animal species, several of which have already been described as potential hosts, specifically dogs (4/55), cat (1/19), and sheep (1/6). In dogs and cats, D. fragilis has been previously detected by PCR, whereas in sheep it was detected by traditional coproscopic methods [ 38 , 40 , 55 ]. In addition, we found D. fragilis in rabbits (5/13), horses (2/15), goat (1/4), and guinea pig (1/2).…”

“…The genetic diversity of D. fragilis appears to be low, and so far, only two genotypes have been proposed based on the variability of three genes (SSU rRNA, EF1, actin) [ 16 , 43 , 59 , 60 ]. However, most studies dealing with molecular or phylogenetic identification of D. fragilis isolates describe a predominant occurrence of Genotype 1 in different geographical areas, in different human cohorts (symptomatic versus asymptomatic individuals) and in animals [ 16 , 24 , 40 , 41 ]. Our nineteen SSU rDNA sequences of D. fragilis obtained from human samples also belong to Genotype 1 according to our phylogenetic analyses, and the sequences appeared in the phylogenetic tree together with Genotype 1 sequences from GenBank.…”

“…To determine the genotypes of D. fragilis in animals, the partial SSU rDNA sequences obtained by cPCR (∼850 bp) are required. So far, only the occurrence of Genotype 1 has been described in pigs, cattle and budgerigars [ 40 , 41 , 44 ].…”

“…Regarding the host range, D. fragilis has only been detected in a few non-human species, most likely due to the lack of molecular epidemiological studies and the small number of animal species studied. To date, D. fragilis has only been detected in domestic pigs [ 32 , 33 ], non-human primates [ 34 , 35 , 36 , 37 ], cats and dogs [ 38 ], rats [ 39 ], and more recently in cattle [ 40 ] and pet budgerigars [ 41 ]. As part of the search for suitable experimental models for D. fragilis , laboratory mice also appear to be a susceptible host [ 12 , 42 ].…”

Observations on the transmission of Dientamoeba fragilis and the cyst life cycle stage

“…It was suggested that D. fragilis may form cysts in an unidentified animal species (Jepps and Dobell, 1918 ) indicating the potential for zoonotic transmission. Dientamoeba fragilis has been reported in several animal species including non-human primates, budgerigars, rats, cattle, sheep and pigs (Chan et al ., 2016 ; Galán-Puchades et al ., 2021 ; Stark et al ., 2008 ; Yetismis et al ., 2022 ; Yildiz and Erdem Aynur, 2022 ). Knowles and Das Gupta ( 1936 ) detected Dientamoeba in stool of a captive macaques using iron haematoxylin staining methods (Knowles and Gupta, 1936 ).…”