First report ofOnchocerca lupifrom Israel and confirmation of two genotypes circulating among canine, feline and human hosts

Abstract

Onchocerca lupi is a parasitic filarioid and the causative agent of canine ocular onchocercosis, a zoonotic disease of domestic dogs with sporadic reports in humans. A 13-year-old dog with no travel history outside of Israel was presented to an ophthalmology veterinary clinic in Israel with severe right ocular and periocular disease. After surgical exploration, thin helminths were removed from the dorsal sclera of the eye and identified as Onchocerca lupi by polymerase chain reaction according to the cytochrome c oxidase subunit I (cox1), reduced nicotinamide adenine dinucleotide dehydrogenase subunit 5 (nad5) and 12S rRNA genes. Phylogenetic trees and haplotype networks of the cox1 and nad5 genes confirmed the circulation of two genotypes: genotype 1 with worms from dogs, cats and humans from both the Old and New Worlds, and genotype 2 with specimens from Portugal and Spain. The Israeli sequences clustered in genotype 1 and were identical to O. lupi from the USA. Evidence of two genotypes separated geographically sheds light on the phylogeography and evolution of this zoonotic pathogen, and suggests a diverse pathology observed in different regions of the world.

Genetic and geographical delineation of zoonotic vector-borne helminths of canids

“…However, due to the shortness of the 12S rRNA (298 bp) and nad5 (393 bp) they used, only the cox1 delimitation is discussed here. As an example, O. lupi reported as genotype 1 47 was herein found to encompass four groups of haplotypes: (i) sequences from USA, Hungary, Israel, Greece and Germany, (haplotype 1), (ii) sequences from Portugal (haplotype 2), (iii) sequences from Spain (haplotype 3) and (iv) sequences from Turkey (haplotype 6). In addition, to the different methods used to delineate the phyletic diversity and the difference in the size of the analysed sequences (570 bp versus 652 bp in the present study), the sequence dataset of Rojas et al lacks sequences from the other haplotypes delineated here, such as sequence from Germany (GenBank accession number: KP347443, haplotype 7), Portugal (GenBank accession number: GU365879, haplotype 4) and Iran (GenBank accession number: JN863696, haplotype 5), which explains the differences in haplotype delimitation.…”

“…A remarkable diversity with seven genotypes was recorded among sequences from the neglected zoonotic O. lupi . The number of haplotypes of O. lupi was previously investigated by Rojas et al using three mitochondrial markers ( cox1 , 12S rRNA and NADH-ubiquinone oxidoreductase chain 5 ( nad5 )) and two phylogenetic methods (e. g., ML phylogeny and haplotype network) 47 . Rojas et al reported two well-separated genotypes, one with worms from the Old and New Worlds and one from Portugal and Spain.…”

“…To assess the genetic diversity throughout A, B and C datasets, the all-against-all sequence comparison with genetic distance clustering was performed using the software TaxI2 Tool 56 . A priori -defined intraspecific genetic distance thresholds of 0.15 and 0.02 for the cox 1 and 12S rRNA sequences, respectively, were assessed to identify representative haplotypes as previously described 13 , 47 . To validate the haplotypes delineation, reference sequences for each haplotype were selected from A, B and C datasets and aligned using MAFFT 57 .…”

Cryptic diversity in a gastrointestinal acanthocephalan of New World primates from Costa Rica

“…Cryptic and genotypic divergence may lead to differences in pathogenicity, as observed in the canid nematode Onchocerca lupi 27 . In the present study a severe tissue in ammation was induced by infection with P. elegans in squirrel monkeys.…”

Autochthonous Onchocerca lupi infection of a domestic dog in Austria

“…Other arthropods have also been considered, but evidence of competent transmission is still missing [ 10 – 12 ]. This parasite has been documented in Europe, America, Africa, and Asia [ 1 , 13 – 15 ]. In Europe, the Iberian Peninsula and Greece are known to be endemic areas, but cases have also been reported from Romania, Hungary, and Germany [ 8 , 16 – 19 ].…”