Molecular identification and phylogenetic analysis of Dipetalonema evansi (Lewis, 1882) in camels (Camelus dromedarius) of Iran

Abstract

Despite the economic importance of camels, the parasites that affect them have not received adequate attention so far and molecular studies are scarce compared to other livestock. In this study, we characterized peripheral blood microfilariae in 200 healthy one-humped camels (Camelus dromedarius) from south-east Iran by microscopy and molecular tools to receive a more detailed insight into prevalence and species that affect them. Moreover, adult specimens of the filarial nematode Dipetalonema evansi were collected from the carcass of an infected animal. Microscopic examination was performed on Giemsa-stained blood smears, and blood was also spotted on Whatman FTA(®) cards for DNA analysis. Genomic DNA was extracted, and PCR was carried out for the detection of filaroid helminths, followed by sequence analysis of positive samples. Four samples were positive for microfilariae by microscopy, while 16 animals (8 %) were positive by PCR. Sequence analysis revealed D. evansi in all cases. Phylogenetic analysis of a cytochrome C oxidase subunit I (COI) sequence of filaroid nematodes showed that most species in a single genus cluster in the same clade; however, D. evansi and D. gracile are not monophyletic and branch rather at the base of the tree. Further studies on the life cycle of D. evansi, specifically the identification of intermediate host(s), have become feasible with the provision of the first specific COI sequences in this study.

Vector-borne bacteria in blood of camels in Iran: New data and literature review

“…One camel positive for Anaplasma spp. in Shahr-e-Babak was co-infected with filaroid Deraiophoronema evansi detected in a previous study [27]. The PCR screenings for Borrelia burgdorferi, Bartonella spp.…”

“…Deraiophoronema evansi was detected in 16 out of 200 samples and one positive sample each with Theileria annulata and Trypanosoma evansi using PCR and sequencing were found. For details on the study population and method of sampling see Sazmand et al [26,27]. Thin blood smears were prepared from each sample, and stained with Giemsa for light microscopic examination.…”

Parasitic diseases of camels in Iran (1931–2017) – a literature review

“…Microfilariae of D. evansi were reported from blood samples in 0.88%–46.7% of the studied camels [24, 61, 85, 98, 110, 124, 129, 141]. Recently, D. evansi was detected in the blood of 8% of 200 examined camels by PCR and sequencing methods [142]. In this study, analysis of a cytochrome C oxidase subunit I (COI) sequence of filaroid nematodes showed paraphyly of Dipetalonema evansi and Dipetalonema gracile .…”

Morphological and molecular characterization ofOnchocerca fasciata(Nematoda, Onchocercidae) from dromedary camels (Camelus dromedarius) in Iran

“…A few studies have been performed on the histochemical distribution of several hydrolytic enzymes and dehydrogenases in adult O. fasciata [ 30 , 31 ] and fine structure of female specimens have been described using transmission electron microscope examination [ 13 ]. Similarly, the molecular characterization of filarial parasites of camel is scarce with only two publications including sequences of either O. fasciata [ 23 ] or D. evansi [ 40 ]. These phylogenies were based on only two or three mitochondrial genes and are characterized by unresolved topology, not clearly identifying relationships between the species.…”